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G eochem ical investigation of early P roterozoic igneous rocks
in northern M ichigan and th e northeast portion o f W isconsin,
U .S .A .
Wee, Soo Meen, Ph.D .
Michigan State University, 1989

UMI

300 N. Zeeb Rd.
Ann Arbor, MI 48106

Geochemical investigation of early Proterozoic igneous rocks in
northern Michigan ana the northeast portion of Wisconsin, U. S. A.
by
Soo - Meen Wee

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of
DOCTOR OF PHILOSOPHY
Department of Geological Sciences

1989

ABSTRACT
Geochemical investigation of early Proterozoic
igneous rocks in northern Michigan and the northeast
portion of Wisconsin, U.S.A.
by
Soo-M een Wee

Early Proterozoic igneous rocks in northern Michigan and northeastern
Wisconsin consist of a complex assemblage of lavas, sills, and dikes. These rocks
were m etam orphosed to varying degrees during the Penokean Orogeny (1.85 - 1.9
G a), however, the chemical compositions of the rocks are well within the limits of
m odem volcanic suites.
Intrusive and extrusive early Proterozoic rock samples from the studied area
w ere analyzed for major, rare earth, and selected trace elements in order to
constrain the petrogenetic relationship between the intrusive and extrusive rocks
and to establish the paleotectonic environment of the area.
This investigation confirms that the dikes and volcanic piles (Hemlock
volcanics and Badwater greenstones) are comagmatic, and suggests that the dikes
served as feeders to the volcanic piles.

The geochemical characteristics of the

studied lavas and dikes are typical of continental tholeiites and no alkaline rocks
were found.

The studied rocks exhibit a relatively wide compositional range in

which the least evolved samples show a similar elem ental abundances to that of
present day T-type MORB. The chemical features of these rocks can be explained
by crustal contam ination of parental magma which was derived from a relatively
undepleted lithospheric upper m antle source. The T-type MORB-like parent was

modified by crustal contam ination process and the chemical compositions changed
to that of continental tholeiites as the rock evolved.
Interpretations of the chemical characteristics of these rocks, based on
m odem analogs, favor their em placem ent in an extensional tectonic regime.

ACKNOWLEDGMENTS

I would like to thank my advisor, the late Dr. W ilband for all his help,
encouragem ent, and advise during the preparation of this thesis. His willingness to
take the tim e (even during hospitalization) to answer questions and assist me in any
way is greatly appreciated. I am particularly indebted to him for his help in the
field. I also would like to acknowledge the interest and assistance of committee
members.
I would like to thank Dr. Fujita for his guidence 1 hrough the duration of my
endeavor and for his friendship. Also I appreciate his encouragem ent and advise
when necessary.
I would like to thank Dr. Vogel for his reviewing and critiquing the thesis. I
appreciate his effort in making a return trip from California to attend my defense.
I would like to thank Dr. Cambray for critical reviewing of my thesis.
I would also like to thank my parents who were behind me all the way, and
fellow students and colleagues, Dave Cook, Jim Mills, Jim G uentert, Ben Schuraytz,
Bob Brown, and Myeung Yi.
I am grateful for Chevron Oil Company for helping with field expences and
Michigan State University for providing a teaching assistantship for my tenure at M.
S. U.
Special thanks to go to my parents and my entire family for their
encouragem ent throughout my entire academic career, and to Seung-Youn, my wife,
for her undying support and patience during long nights at the Natural Science
Building.

ii

TABLE OF CONTENTS

ABSTRACT
ACKNOW LEDGM ENTS
IN TR O D U CTIO N

1

R E G IO N A L G E O L O G Y

9

D ESCRIPTIO N O F STU D IED RO CK UNITS
1. Dike Swarms

16

2. H em lock Volcanics

18

3. Badw ater G reenstones

19

SAM PLING AND ANALYTICAL M ETHODS

20

ANALYTICAL RESULTS
1. M ajor Elem ents

23

2. Trace and R are E arth Elem ents

36

a) Dikes

43

b) Hem lock Volcanics

46

c) Badw ater G reenstones

46

DISCUSSION
1. Comagmatism

57

2. Chemical variation of the evolved rocks

69

3. Accessment of Crustal Contam ination

81

4. M agma Source

90

iil

G E O C H E M IC A L IN TERPRETA TIO N S O F TECTO N IC SETTING
1. Test of tectonic setting using immobile elem ent tectonic discrimination diagrams
102
a) Ti - Z r

103

b) Ti - Z r - Y

106

c) Z r/Y - Z r

106

2. G eochem ical patterns of the rock suites

112

3. Tectonic model

125

CONCLUSIONS

131

R E FE R E N C E S

134

A PPEN D IX 1: CIPW norms and major elem ent compositions

145

A PPEN D IX 2: Trace and R E E compositions

159

A PPEN D IX 3: Sample locations and m ap

179

lv

LIST OF TABLES

Table . Stratigraphic relationships in the study area in northern Michigan and the
northeast portion of Wisconsin.
4
Table 1. Accuracy of the X R F analysis.

22

Table i. Average chemical compositions of the rock groups.

37

Table -. Comparision of chemical compositions between Precam brian X dikes and
the A rchean (?) dikes.
47
Table

i.

Averages of major elem ent compositions of M ORB from different
localities.

62

Table i. Comparision of averaged MgO, N a20, and CaO abundances between the
group I and group II samples.
64
Table

a) Summary of Pearce elem ent ratios used in the evalution of petrologic
hypotheses, b) Slopes and intercepts of the investigated rock suites for
Pearce elem ent plots.
73

Table 1. Partition coefficients of Ce and Yb to olivine, clinopyroxene, and
plagioclase.

81

Table KPrimitive liquid composition by back calculation for olivine addition. 95

V

LIST OF FIGURES
Figure 1. Early Proterozoic tectonostratigraphic terranes in the southern Lake
Superior region.
2
Figure 2. G eneral geology and early Proterozoic tectnostratigraphic terranes in the
south-central Lake Superior region.
6
Figure 3. Possible plate tectonic models to explain the tectonic evolution of the
southern Lake Superior region.
14
Figure 4. Chemical diagrams used to classify the igneous rocks of this investigation.
24
Figure 5. Dikes, Hemlock volcanics, and Badwater greenstones on N a ? 0 vs. 100 x
K 2 O/XK2 O + N a2 0 ) diagram.
27
Figure 6. Variation of major elements vs differentiation index (F eG /(F eO : MgO)).
30
Figure 7. Diagrams using TiO ? to detect degree of depletion in magma source.
34
Figure 8. Variation of trace elements vs differentiation index (F eO /(F eO + MgO)).
38
Figure 9. Chondrite normalized R E E patterns of the dikes.

44

Figure 10. Chondrite normalized R E E patterns of the Hemlock volcanics.

48

Figure 11. Chondrite normalized R E E patterns of the Badwater greenstones. 50
Figure 12. Chondrite normalized R E E patterns of the averages of the studied rock
suites and regional crustal rocks.
53
Figure 13. Chondrite normalized geochemical patterns for the averages of the
studied rock suites.
55
Figure 14. Conserved elem ent plot using P /K and T i/K for the dikes, the Hemlock
volcanics, and the Badwater greenstones.
59
Figure 15. Conserved elem ent plot using P /K and T i/K for the calculated means of
the studied rock suites, and M ORB from different areas.
66
Figure 16. Simplified molecular proportion ratio plot (oxides X, Y, and Z ) showing
changes of the slope and intercept of original trends due to alteration or
metamorphism.
70
Figure 17. Pearce elem ent ratio diagrams Y =0.5 (Mg + Fe) / K and X = Si / K
and X = Ti / K for the dikes, Hemlock volcanics, and Badwater
greenstones.
74
vi

Figure 18. Pearce elem ent ratio plots to test differentiation in basaltic rocks for
specific m ineral assemblages.
76
Figure 19. C e/Y b vs. Ce ppm plots.

82

Figure 20. C e/Y b vs. Ce ppm plots for the dikes, the Hemlock volcanics, and
Badwater greenstones with FC and AFC models.
84
Figure 21. Plots of N b # vs. mafic index (F /F + M) for the dikes, Hemlock volcanics,
and the Badw ater greenstones.
88
Figure 22. T h /L a vs. Th, T h /C e vs.Th, T h/S m vs. Th, and T h /Y b vs.Th plots for the
studied rock suites.
92
Figure 23. Chondrite normalized R E E abundance patterns as a function of the
degree of melting of calculated mantle source.
96
Figure 24. Pseudo-liquidus phase diagrams for dikes, Hemlock volcanics, and
Badwatergreenstones projected from plagioclase onto the olivinediopside-silica plane and from diopside onto the olivine-plagioclase-silica
plane.
100
Figure 25. Plots of Ti vs. Z r for the dikes, Hemlock volcanics, and the Badwater
greenstones.
104
Figure 26. Plot of Ti-Zr-Y for the studied rock suites.

107

Figure 27. Plot of Z r/Y vs. Z r for the studied rock suites.

109

Figure 28. Geochemical patterns of basalts from known tectonic environments
normalized to N-type MORB.
113
Figure 29. Geochemical patterns of samples of study area normalized with respect
to N-type M ORB.
116
Figure 30. Histogram of percent frequency vs. L a/N b for the dikes, Hemlock
volcanics, and Badwater greenstones.
121
Figure 31. Speculative reconstruction showing the tectonic evolution of the southern
Lake Superior region.
129

vii

INTRODUCTION

The N orth Am erican craton in northern Michigan and northeastern
Wisconsin is composed of a) granitic gneisses and basaltic greenstones of A rchean
(Precam brian W) volcanic-intrusive sequences with possible attendant late A rchean
mafic dike swarms, b) a complex early Proterozoic (Precam brian X) assemblage of
volcanic rocks, sills, and dikes with predominantly basaltic affinities, and c) the late
Proterozoic (Precam brian Y), 1 Ga, Keweenawan basaltic rocks which consist of
dike swarms and several separate basins of lava flows. This investigation is focused
on the early Proterozoic intrusive and extrusive rocks. In spite of extensive mapping
and collection of geochemical data which has continued for many years in southern
Lake Superior region, the petrogenetic relationships among the early Proterozoic
igneous rocks rem ain questionable.
The early Proterozoic Hemlock volcanics, which are a part of a passive
margin assemblage, and the Badwater greenstones of the Crystal Falls terrane
(Figure 1) represent a volcanic and intrusive stage in the form ation of this
geologically complex area within the craton. The widespread intrusion of the early
Proterozoic dikes within, north, and northeast of the Crystal Falls terrane probably
took place during this stage and served as feeders to one or both of the volcanic
piles.
Previous studies (Fox, 1983; Ueng et al., 1988) showed no distinguishable
differences between the Badwater greenstones and Hemlock volcanics based on
major and trace elements. If the Badwater greenstones and Hemlock volcanics are
comagmatic, then the previously suggested stratigraphic position of the Badwater
greenstone with respect to the widespread early Proterozoic Michigamme Slate and
the Hemlock Form ation (see Table 1) needs to be revised (Ueng et al., 1988).

l

Figure 1. Early Proterozoic tectonostratigraphic terranes in the southern Lake
Superior region (A fter U eng et al., 1988).

2

STUDY
AREA
♦
Rocks younger than
early Proterozoic
Early Proterozoic
passive margin assemblage
PRAGMATIC ^ C T E R R A N

e'

S ^

WISCONSIN

^SPSl

S / S S S S yT's&^r.

M INNESOTA

^

FLO R EN C ENSAGARA

TERRANE

1CK) Km

Early Proterozoic
magmatic terrane
A rchean greenstone and
granite terrane
Archean gneiss
terrane

Table 1. Stratigraphic relationships of the area studied in upper Michigan and
northest portion of Wisconsin.
Table la. Stratigraphy of the studied area (Cambray, 1987).
GROUP

IRON RIVER/
CRYSTAL FALLS

BARAGA

Fortune Lk.
Michigamme
Strata
Stambaugh F im ___ Gray Slate
Near
HiawatEa Gw.
” CongiomeTaTe** ^Fence Lk.

MENOMINEE

RivertonBIF
Dunn Creek ST
Badwater Gs.

CHOCOLAY

??????????

MARQUETTE
TROUGH

AMASA UPLIFT

Fence R./Araasa
'* ^Formation
Hemlock Fm.

RandviheDoi “

ARCHEAN BASEMENT

Upr. Slate
Bijiki BIF
Lr. Slate
Clarksburg vol.
^
.^Goodrich Q.
^N egaunee BIF
Siamo Slate
-^Ajibik Q.
„ Kona Dol.
Wewe Slate
Mesnard Q.
-^Enchantment Lk.

Table lb. Stratigraphic relationships of the area studied in Upper Michigan (Van Hise and Baylay,
1897; James et al., 1961,1968; Cannon and Klasner, 1975; compiled by Cudzilo, 1978).

Age (m.y.)

Stratigraphic Units
Iron and Dickinson Counties
(Southern Upper Peninsula)

1850-1900

Marquette Trough

Peavey Complex
Paint River Group
Fortune Lakes Slate
Stain Baugh Formation
Hiawath Graywacke
Dunn Creek Slate
Baraga Group
Badwater Greenstone
Michigamme Formation

Fance River Formation
Hemlock Formation
Goodrich Quartzite

1950

Baraga Group
Michigamme Formation
Upper Slate Member
Bijiki Iron Formation
Lower Slate Member
Clarksburg Volcanic Member
Greenwood Iron Formation
Goodrich Quartzite

Menominee Group
Vulcan Iron Formation
Felch Formation

Menominee Group
Negaunee Iron Formation
Siamo Slate
Ajibik Quartzite

Chocolay Group
Randville Dolomite
Sturgeon Quartzite
Fern Creek Formation

Chocolay Group
Wewe Slate
Kona Dolomite
Mesnard Quartzite

4

Two major early Proterozoic tectonic provinces in the southern Lake
Superior region, the northern passive margin assemblage and the southern
magmatic arc complex (Figure 2), have given rise to controversial interpretations of
their tectonic evolution. Studies have suggested that the northern assemblage was
subducted below and accreted to the arc terrane during the Penokean Orogeny
about 1.85-1.9 G a (Cambray, 1977, 1978; Larue and Sloss, 1980; Larue and Ueng,
1985). However, Van Schmus (1976) proposed that the arc complex is a rem nant of
a Proterozoic A ndean type continental margin and that the deform ed and
m etam orphosed northern assemblage represents a deform ed back-arc or foreland
basin assemblage. U pon discovery of Archean basem ent in Wisconsin, V an Schmus
(1977) was compelled to relocate the subduction zone further south. G reenberg and
Brown (1983) suggested that Penokean volcanism resulted from the rifting of the
continental margin, which was sutured to the magmatic arc terrane during the
Penokean Orogeny. In addition to the models developed from the plate tectonic
paradigm, the Penokean Orogeny has been interpreted as a product of vertical
remobilization of intracratonic basem ent (Sims, 1976, 1980; Klasner, 1978; Morey,
1978; Foose, 1981). In this model, two crustal blocks, a granite-greenstone terrane
and an older, northerly, gneiss terrane, were welded together in the A rchean to form
the basem ent for all younger rocks in the region. Sims (1976) also invoked a crustal
foundering mechanism to explain the deposition of early Proterozoic sedimentary
and volcanic m aterial in an intracratonal basin upon the A rchean crust.

The

foundering process implies subsidence but not the actual developm ent of rifting.
Penokean

deformation,

metamorphism,

and

intrusion

were

attributed

to

reactivation of the suture between the two A rcheanjterranes. Studies in the area
suggested that available data best fits the Cambray's (1977, 1978) arc-continent
accretion model (Fox, 1983; Lovett, 1984; Ueng et al., 1988), however, more
docum entation is needed.

5

Figure 2. G eneral geology and the early Proterozoic tectonostratigraphic terranes in
the southcentral Lake Superior region (A fter Ueng et al., 1988).
(G R: G reenwood Quad.; IP: Ishpeming Quad.; RP: Republic Quad.;
KR: K iem an Quad.; H.R.: Hem lock River)

6

e a°3 0 -

0 8 ° 15'
, /

88°00‘

TAV LO A m im c

m

RY 8TA L FALLS

7

In spite of their great age, early Proterozoic rocks may still retain many of
their original chemical characteristics. Previous studies of the dike swarms are few
and could not be used to evaluate petrochem ical variations within the swarms either
tem porally and spatially, nor may they be used to allow meaningful comparisons to
the H em lock and Badw ater volcanic piles.

Thus, m ore data must be obtained

before reasonable petrogenetic/tectonic interpretations can be m ade for this stage
of developm ent of the N orth Am erica craton. Such a knowledge of petrogenetic
history will provide constraints on the tectonic evolution of the study area. The
subsequent Penokean Orogeny (about 1.85 - 1.9 Ga, Sims et al., 1980; V an Schmus,
1976), which was related to the collision of the northern passive margin terrane and
southern magmatic arc terrane, resulted in the widespread m etam orphism and
structural deform ation in the Precam brian X m etasedim entary and metavolcanic
sequences and Precam brian W basem ent rocks of the southern Lake Superior
region.
The m ajor objective of this research is to analyze and evaluate the
petrochem istry of the

early Proterozoic intrusive

and extrusive

rocks for

relationships between the dike swarms and the Hemlock and Badwater volcanic
piles. The other objective of this study is to establish the petrogenetic origin of the
rock suites to determ ine w hether the tectonic environment was suboceanic or
subcontinental and w hether it was subduction related or rift related.

8

REGIONAL GEOLOGY

The Precam brian geology of the northern Michigan and northeastern
Wisconsin is very complex and is related to several tectonic events. The area has
been involved in two major orogenic episodes, the Algoman Orogeny (2.7 G a) and
the Penokean Orogeny, which occurred about 1.85 - 1.9 G a ago and included
deform ation, regional m etamorphism, and extrusive and intrusive igneous activities
(Cannon, 1973; V an Schmus, 1976).
The area was divided into four tectonostratigraphic terranes by Larue (1983).
The terranes are 1) the passive margin terrane, 2) the Crystal Falls terrane, 3) the
Florence-N iagara terrane, and 4) the northern Wisconsin magmatic arc terrane
(Figure 1).
T he

passive

margin

terrane

is

composed

of

three

transgressive

m etasedim entary sequences deposited unconformably on Archean sialic crust. The
m etasedim entary sequence, from the oldest to youngest, are the Chocolay, the
M enom inee and the Baraga Groups. T he Chocolay G roup has characteristics in
common with a m odern miogeosynclinal or shelf sea facies association (Cambray,
1978).

Larue and Sloss (1980) suggested that the Chocolay G roup sediments

accum ulated in elongated basins and on platforms between the basins.

The

elongated sedim entary basins, which were compressed to form the structural troughs
during the Penokean Orogeny, occur at sites of early Proterozoic structural troughs,
including the M arquette, Felch, and M enominee troughs (Figure 2). The tectonic
conditions were apparently relatively stable during the deposition of Chocolay
G roup strata.
T he M enom inee G roup is a fining upward sequence with a basal quartzite
overlain by lam inated argillites, and chemical precipitates with local conglomerates

9

(Klasner and Cannon, 1978).

It was deposited unconformably on the lower

Precam brian basem ent rocks with mild tectonic disturbances during sedim entation
(V an Schmus, 1976; Cambray, 1978). In the M arquette trough, the thick Siamo
Slate occupies a position between the quartzite and iron formation. Because the
Siamo Slate is a turbidite unit in part, and because it is restricted to the M arquette
trough, it has been suggested that the M arquette trough was an actively subsiding
basin during deposition of M enominee Group sediments (Larue, 1983).

Rapid

subsidence of the area resulted in a deep water environment. An extensive period
of erosion seems to have occurred before the first form ation of Baraga G roup was
laid down (Cambray, 1978).
The Baraga G roup is composed of a basal quartzite, a iron formation, and
the tholeiitic basalts of the Hemlock Formation, followed by deposition of turbidites
of the Michigamme Slate (Bayley et al., 1966; James et al., 1968; Larue and Sloss,
1980). The present distribution of volcanic rocks in the Baraga G roup is mostly
limited to the west of Mitchigan River trough where they rest unconformably upon
A rchean crystalline basem ent and the Chocolay dolomite. The composition of these
volcanic rocks change from felsic in the northeast to mafic to the southwest (Cannon
and Klasner, 1976). In this area, several differentiated intrusives (e.g., Kiernan Sills,
and the mafic plutonic stock complex at Pevey Pond) were emplaced into the
Hemlock Formation.
The Crystal Falls terrane is composed of the Paint River G roup and the
underlying Badwater greenstones, a thick units of pillow basalts and greenstones
(James et al., 1968).

The contact of Paint River G roup with the underlying

Badwater greenstone has been inferred to be a fault along the northern border of
the Crystal Falls terrane (Larue, 1983), or an unconformity (James et al., 1968).
Because the Paint River G roup was not deposited uneqivocally on Archean
crystalline basem ent and is unlike other strata in the Lake Superior region, Larue

10

(1983) defined the Crystal Falls terrane as a separate tectonostratigraphic terrane.
The absence of the Archean sialic crust was inferred from the positive Bouguer
gravity anomalies (4.3 mgal for the Crystal Falls terrane versus -45 mgal for the
A m asa Oval in Paddock, 1982) compared to the northern passive margin terrane
(U eng et al., 1988). The Paint River Group, a sequence of deposits derived in part
from terrigeneous sources, may be equivalent to the M enominee G roup (Cambray,
1978), however, others believe the Paint River G roup to be separated from the
M enom inee G roup by the Baraga G roup (James, 1958; Cannon and Gair, 1970).
Cambray (1987) proposed that the lower part of the Paint River G roup correlates
with the M enominee G roup and the upper part correlates with the Baraga Group.
The Florence-Niagara terrane consists of eight major fault-bounded packets
that strike E-W to NW-SE (Ueng and Larue, 1988). The fault-bounded packets
containing highly deformed rocks that are, for the most part, correlative with the
passive margin terrane (Larue, 1983).

The Florence-Niagara terrane has been

interpreted as a fragment of the passive margin terrane which was accreted to the
forearc area of the magmatic terrane during the Penokean arc-continent collision
(Larue, 1983; Larue and Ueng, 1985; Ueng et al., 1988).
T he magmatic arc terrane consists of several cores of granitoid to gneissic
rocks m antled by highly deformed metavolcanic, metapellitic, and metagabbroic
rocks. This area shows a record that records a major interval of calc-alkaline and
tholeiitic volcanism at 1.86 - 1.87 G a (Sims, 1988).

Granitoid intrusions, which

compose about one-quarter of the exposed part of the magmatic arc terrane,
accompanied

and followed

the volcanism.

The

metavolcanic

rocks bear

geochemical signatures typical of volcanic arc environments (Van Schmus, 1976;
Cudzilo, 1978; G reenberg and Brown, 1983; Ueng et al., 1988).
Dike swarms are exposed mostly in the northern passive margin terrane with
various orientations. Basaltic dikes were intruded into the Archean basem ent and

11

early Proterozoic m etasedim entary sequences.

In the M arquette area, they cut

rocks as young as the Clarksburg Volcanics M em ber of the Michigamme Form ation
but not younger rocks (G air and Thaden, 1968); in the western part of northern
Michigan, they cut the Ironwood Iron Form ation but not the younger Michigamme
Form ation and its correlatives (Sims, 1980). Cannon (1975) proposed that these
dikes were probably em placed in the Baraga G roup as an equivalent to the basaltic
extrusives. Although the exact relative age of any individual dike is indeterm inate,
some dikes, if not most, have been interpreted as predating the Penokean Orogeny
(Cannon, 1975; Baxter and Bom horst, 1988).
Low pressure, m oderate to high tem perature m etam orphism occurred
around four distinct nodes in the northern Michigan (James, 1955). M etamorphic
isogrades form annular nodes which show chlorite zones at the periphery to zones as
high as sillimanite at the centers. Although some uncertainty exists in interpreting
of the cause and age of metamorphism, it is generally considered to be a Penokean
event associated with deform ation and plutonism in the region.
The causes of the tectonic activity of the Penokean Orogeny have been
variously interpreted by previous workers.

The traditional tenet of vertical

rem obilization of intracratonic basem ent has been suggested by Cannon (1973),
Sims (1976), and Morey (1978). They suggested that the principal cause of the
Penokean Orogeny is not the regional horizontal compression, but the large vertical
movement of fault-bounded blocks of the A rchean basement. The foundering of
continental crust to form an intracratonic basin above and along the unstable
A rchean boundary is attributed to differential therm al movement of the crust by
crustal, and perhaps also mantle, processes (Sims et al., 1980).
Van Schmus (1976) interpreted the Chocolay and M enominee Groups as
possibly indicating passive margin deposition, whereas the Baraga G roup strata
were deposited in a foreland or back arc basin.

12

He tentatively modelled the

Penokean Orogeny as a product of a consuming continental margin, with ocean
floor (to the south) subducted toward the north, under the foreland basin (Fig. 3a).
A fter discovery of A rchean basem ent in Wisconsin, he relocated the subduction
zone further south.
The arc-continent collision model was proposed by Cambray (1978). This
model proposed that the Chocolay G roup was deposited in a cratonic setting and
that the strata of the M enom inee G roup show features which are inferred to
indicate initiation of rifting (Fig. 3b). In this model, the Penokean Orogeny was
caused by the collision of a continent to the north with an arc to the south. The
deform ation in the Penokean Orogeny was produced by horizontal compression and
was transm itted from the basem ent to the folded cover rocks by ductile shear in the
basem ent following collision (Cambray, 1984). This collision was the culmination of
intraplate rifting and associated volcanism.
The early Proterozoic tectonic evolution of the southern Lake Superior
region has been alternatively interpreted by a foredeep model (Hoffman, 1988).
Foredeeps are linear asymmetric basins that migrate in front of, and become
incorporated within, foreland thrust fold belts. They develop as a flexural response
to loading of the continental lithosphere by thrust sheets (Fig. 3c).

13

Figure 3. V arious plate tectonic models to explain the tectonic evolution of the
southern Lake Superior region.
a) A reconstruction of the margin of the A rchean craton about 1.9 G a ago
during the early stage of the Penokean Orogeny (Van Schmus, 1976).
b) Schematic diagram showing plate-tectonic evolution of the southern Lake
Superior region (Larue and Sloss, 1980, model after Cambray, 1978).
1. Sedim entation of the Chocolay and M enominee G roup on the
passive rifted margin. 2. Baraga G roup sedim entation. 3. Collision
with Cordilleran-type continental margin on southern magmatic arc
complex.
c) Evolution of an oceanic trench (A) into a foredeep (B) by attem pted
subduction of a passive continental margin (Hoffman, 1988).

14

T * 1 9 0 0 Ma
Michigan

SE

NW

m a n t la

A.

(After Van Schmus, 1976)
Michigan

Wisconsin

Oo°*fon45" *
• | * 1

U-JLJL.1-J.J1-

- v

i> i t- C

P«nok«an

jO l^ .N y s V :

?X v\> C tE $?

Orogeny
Archean
basement

1 0 0 km

B. (After Larue and Sloss, 1980, model after Cambray, 1978)

cont i nent al c r u s t
l ilhospheric
oceanic crust

mant le

fold-andt h r u s t belt

active
foredeep

B

t
i nitial-r if t
deposits

C.

passive-margm
deposits

trench-foredeep
deposits

(A fter Hoffman, 1988)
15

DESCRIPTION OF STUDIED ROCK UNITS

1. Dikes
The early Proterozoic dike swarms are exposed throughout the passive
margin terrane. The dikes are steeply dipping at angles ranging from 70 degrees to
vertical and have widely varying strikes (Myers, 1984). These basaltic dikes intrude
A rchean basem ent rocks and the lower part of the early Proterozoic sediments.
There is an indication that most of the m etadiabase dikes were intruded prior to the
deposition of the G oodrich quartzite (Boyum, 1975), however, Cannon (1974)
suggested that the dikes are related to the Clarkburg volcanics of the Michigamme
Form ation which is younger than the Goodrich quartzite.

Although the exact

relative age of any individual dike is indeterminate, as a whole, these dikes have
been interpreted as predating the Penokean Orogeny.
In some areas (e.g., Republic and Ishpeming quadrangles), porphyritic dikes
were found which contain euhedral to subhedral phenocrysts of plagioclase. These
dikes typically trend north-south (Baxter and Bomhorst, 1988).

Cannon (1975)

noted that some dikes in the Republic area are distinctly porphyritic and cut the
A rchean granites and gneisses, but do not cut the early Proterozoic sediments.
Puffett (1975) also noted the existance of coarsely porphyritic mafic dikes which
may be in Archean age. Baxter and Bom horst (1988) tentatively interpreted these
porphyritic mafic dikes as equivalent to the Archean Matachewan dike swarm of
O ntario which have an age of 2690 ± 93 Ma.
The mineralogy and texture of the dikes vary widely through the area. The
dikes consist predominantly of amphibole (primarily hornblende), plagioclase,
biotite, chlorite, and a variable amount of oxide minerals. O ther minerals present
are epidote, clinozoisite, quartz, carbonate, and apatite as a minor phase. Some
samples show a well developed orientation of hornblende and biotite grains.

16

Diabasic texture is often found with almost complete alteration of pyroxene to
hornblende. Plagioclase generally occurs as subhedral to anhedral, fine to medium,
grains which comprise from 15% to 50% of the rock. Sericitization of plagioclase is
very common and, in some cases, grains are partially replaced by carbonate.
Inclusions of biotite, hornblende, and apatite are very common.
Most of the dikes have a varying amounts of hornblende (10% to 50%) with
mostly anhedral to subhedral shapes. They often show twinning and inclusions.
They are, in some cases, altered to chlorite and biotite.
trem olite

Some samples show a

composition (Greenwood quadrangle) and, in some cases, fibrous

actinolite is present.

Based on the color, two different types of hornblende are

recognized. O ne is dark green and faintly blue, and other is a blue green variation.
The different colors in hornblende are usually caused by the change in the
Fe^ + /F e ^ + ratio, which reflects changes in metamorphic conditions, especially in
tem perature.

With increasing metamorphism, the

H2 O

content and

the

Fe^ + /F e ^ + ratio tend to decrease (Miyashiro, 1968) and the color changes from
blue to green and green to brown. It is likely, therefore, that the blue hornblende
represents a lower grade metamorphism than green ones.
Chlorite is present in nearly all samples in varying amounts (trace to 15%).
It usually occurs as aggregates of fine shreds and alteration products of hornblende
and biotite. Biotite occurs in most samples in the high metamorphic grade zones,
and occurs as replacem ent of hornblende. Primary augite was seen in some samples
from the W akefield quadrangle.

Most of them

have been partially altered to

hornblende.
M ineral assemblages are consistent with the greenschist and amphibolite
facies of metamorphism. Low grade mineral assemblages in some dikes, such as
plagioclase + chlorite + epidote + (carbonate) or plagioclase + actinolite +
epidote + (carbonate) indicate a typical greenschist facies. Dikes with assemblages

17

such as plagioclase + hornblende + (epidote) or plagioclase + hornblende +
biotite + (epidote, chlorite) indicate a higher grade m etam orphism typical of the
am phibolite facies.

2. Hem lock volcanics
The Hem lock Form ation was nam ed after extensive exposures along the
Hem lock River on the west side of the Amasa oval, in northw estern Kiernan
quadrangle, northeast of the town of Amasa (G air and Wier, 1956). The Hemlock
Form ation consists mainly of a thick series of altered volcanic flow rocks, tuffs, and
agglomerates, forming massive to schistose and slaty greenstone.

It reaches a

thickness of 750 to 9000 m eters near Amasa, but thins regionally to the north, south,
and east (Bayley, 1959; Wier, 1967). W here it is thinnest, basalt flows dom inate the
lithology (Fox, 1983). The basalt flows are commonly 2 to 20 meters thick (Ueng et
al., 1988), and often have vesicles less than 1 centim eter in diameter.

The

m etabasalt commonly forms knobby outcrops (G air and Wier, 1956). The rock is
massive and dense, and generally has conspicuous joints. Most of the m etabasalt
appears originally to have had fine to medium grained subdiabasic texture (G air and
Wier, 1956). But estimates of original grain sizes are generally difficult to make
because of the destruction of primary fabric during metamorphism.
The m etabasalts are dom inated by actinolite, chlorite, plagioclase, epidote,
clinozoisite, and iron oxides. Common alteration products, apparently derived from
the plagioclase, are clinozoisite with epidote, carbonate, sericite, and chlorite. The
majority of the rocks are m etam orphosed to the greenschist facies and have mineral
assemblages, such as chlorite + epidote (clinozoisite) + plagioclase, chlorite +
epidote (clinozoisite) + plagioclase + carbonate, or epidote + actinolite +
plagioclase + chlorite.

18

3. Badwater greenstones
The Badw ater greenstone is the youngest unit in the Baraga Group. The
greenstone was formed, for the most part, by the m etam orphism of pillow lavas and
tuffaceous and agglomeratic phases (James et al., 1968), which indicate deposition
in a subaqueous environment.
The greenstones are generally massive chloritized basaltic flows but locally
ellipsoidal or slightly foliated.

T he Badwater greenstone consists of plagioclase,

amphibole (actinolite and hornblende), chlorite, epidote, and clinozoisite as the
major constituents; biotite, quartz, and carbonate are minor constituents.

Most

plagioclase occurs as microphenocrysts, but medium sized grains are also found in
the samples from the interior of the flows. Most plagioclase grains are altered to
sericite as well as clinozoisite and epidote, and are often partially replaced by
carbonate. The matrix usually consists of chlorite and very fine grained aggregates
of epidote, clinozoisite, and carbonate.

19

SAMPLING AND ANALYTICAL METHODS

In this study, sampling was focused on the early Proterozoic dikes and
volcanic piles (Hem lock volcanics and Badwater greenstones) in northern Michigan
and northeastern Wisconsin.

Fifty-three samples from dikes (46 Precam brian X

dikes and 7 A rchean (?) dikes), forty samples from the Hem lock volcanics, twentynine samples from Badwater greenstone, and ten A rchean basem ent rock samples
were collected.
W hole rock samples from the early Proterozoic intrusive and extrusive rocks
were analyzed for m ajor and selected trace elements, including rare earth elements
(R E E ). Results of chemical analyses are tabulated in Appendix 2, and sampling
locations and map are listed in Appendix 3. Standardized X-ray fluorescense (XRF)
and Instrum ental N eutron Activation Analyses (INAA) procedures developed at
Michigan State University were used to determ ine whole rock compositions of the
major, trace elements, and R E E.
M ajor and selected trace elem ents were analyzed by a Rigaku (S-Max)
autom ated X-ray fluorescence spectrom eter.
were m ade by the following procedure:

1

)

Glass waffles (for major elements)

1 .0 0 0 0

gram of crushed sample,

9 .0 0 0 0

grams of lithium tetraborate (flux), and 0.160 grams of am m onium nitrate (oxidant)
were mixed with a spatula in Pt-Au crucibles, 2) this preparation was heated and
gently shaken at approximatly 1100 C for 20 to 30 minutes in order to make a
homogeneous liquid, 3) this liquid was then poured into a Pt-Au mold and
transferred to a hot plate for annealing, which was then removed and allowed to
cool to room tem perature. The trace elements Rb, Sr, Nb, Y, Cr, Ni, Cu, Zn, Zr,
and Y were also analyzed by XRF, using pressed powder pellets, with a
sam ple/cellulase (Amercil) binder ratio of 4:1.

20

R E E and Cr, Th, Sc, and H f were analyzed by INAA. Powdered 1.00000
gram (

> 2 0 0

mesh) samples were sealed in polyvinyl vials and irradiated for 18

hours over a 3 day period. T he short lived isotopes, La, Sm, and Sc were analyzed
after 5 to 7 days and other elem ents were analyzed after 2 weeks from irradiation.
Accuracy for m ajor elem ents is within 2% except for P, which is 5.4%. Trace
elem ents by X R F are accurate to within 5% except for Y and Zn, which are less
than 10%.

Accuracy for elem ents by INAA is less than 10%, but where

concentrations are less than 10 ppm (Tb, Lu, and Th), accuracy approaches 15%.
The accuracy of the X R F analysis is listed in Table 2.

21

Table 2. Accuracy of the X R F analysis.

SiOo
AI9 O 3
FeO
MnO
CaO
N a?0
T 1O 9
pJs
2^5
Ba
Cu
Nb
Ni
Rb
Sr
Y
Zn
Zr

M ean

STD.

R eported
„
(USGS-W -2 )

Accuracy

52.65
15.41
9.83
0.167
10.95
2.24
0.63
1.065
0.132

0.109
0.087
0.029

52.68
15.45
9.87
0.167

99.94%
99.74%
99.59%
99.95%
99.18%
98.21%
99.98%
99.72%
93.62%

168.78
105.76
6 .8 6

68.60
18.90
191.08
20.90
72.90
97.74

0 .0 0 1

0.075
0.013

1 0 .8 6
2 .2 0

0.63
1.062
0.141

0 .0 0 1
0 .0 0 2
0 .0 0 1

16.53
2.52
0.67
2.76
0.67
0.41
0.60
0.43
0.99

174
106
6 .8

70.0
2 1 .0

192
23.0
80.0
1 0 0

* from G eostandards Newsletter, Vol VIII, Special Issue, July 1984

22

97.00%
99.77%
99.13%
98.00%
90.00%
99.52%
90.87%
91.13%
97.74%

ANALYTICAL RESULTS

1. M ajor elem ents
The analyzed dikes and flows have

mostly basaltic compositions with a

relatively wide range of SiC> 2 (43-60 %) and are olivine, or less commonly, quartz
normative (see Appendix 1).

A few samples are nepheline normative, possibly

caused by the addition of N a and K during hydrothermal alteration or m etam orphic
recrystallization (Knoper and Condie, 1988). Whole rock chemical analyses of rocks
from the dike swarms, the Hem lock volcanics, and the Badw ater greenstones
indicate that the majority of the rocks fall within the tholeiitic field in an AFM
diagram (Fig. 4a) and within the subalkaline field in an Ol-Ne-Q diagram (Fig. 4b).
Figure 5 shows the results plotted on a Na 2
K2

0

/(K 2

0

+ Na 2

0

0

+ K^O versus 100 *

) diagram (Hughes, 1973). This diagram is useful to evaluate

the effects o f secondary alteration.

Rocks whose compositions lie outside the

envelope ("igneous spectrum") are probably due to elem ent mobility during
secondary and metam orphic alteration (Honkamo, 1987). Although the diagram
shows a few conspicuously deviating samples, the plots of the rock suites from the
study area fall well within the fields of modern volcanic suites on this diagram,
indicating that metam orphic alteration has only been minimal.

M ajor and trace

elem ent composition of these rocks are listed in Appendix 2 and are typical of
continental tholeiites. Com pared with typical oceanic tholeiites, the analyzed rocks
have higher contents of TiC> 2 (1.56 %) and K^O (1.23 % ). The average chemical
composition o f the investigated rocks are listed in Table 3.
The Mg numbers (M gO /(M gO + FeO )) of the dike swarms and Hemlock
volcanics vary between 63 to 26 with most rocks having values of less than 50, while
the Badwater greenstones show a relatively narrow range of Mg numbers (40 to 50).
These relatively low Mg numbers indicate significant fractionation of the rocks, and

23

Figure 4. Chemical diagrams (Irvine and Baraga, 1971) used to classify the igneous
rocks of this investigation, a) A FM diagram, b) Normative nephelineolivine-quartz diagram.

24

FeO

DIKES
B.W. GREENSTONES
HEMLOCK VOLCANICS
THOLEIITIC
m

CALC-ALKALINE

10

Aik

20

30

40

50

60

70

80

90

MgO

*
^
+

SUB AL K A L I
^

*

90
Q

DIKES
B .W . GREENSTONES
HEMLOCK VOLCANICS

Figure 5. Dikes, Hem lock volcanics, and Badwater greenstones on a Na 2 0 vs. 100 *
K.2 0 /(K . 2 0 + Na 2 0 1 diagram. The so-called "Igneous spectrum" (area
betw een solid lines) represents the range of variation of various
m odem volcanic rocks.

27

r.

1-------- 1-------- 1

IGNEOUS
SPECTRUM

ro
oo

100

X K2 0 / ( N a 2 0

* Dikes
a B.W. Greenstones
CD Hemlock Volcanics

such evolved compositions are typical of Precam brian intrusive rocks from other
localities (Condie et al., 1987).
Variations of major elem ents increasing m agmatic differentiation for the
samples from the dike swarms, Hem lock volcanics, and Badwater greenstones are
indexed with mole percentage of F eO /(F eO + MgO) and are shown in Figure

6

.

Analyses of these samples show a fairly well defined variation trend indicating that a
parallel differentiation history is shared by all three suites of rock. The abundances
of Ti 0

2

, P 2 O 5 , and FeO increase with increasing with differentiation index (D.I.),

while MgO, CaO, AI2 Q 3 decrease (Fig. 6 ). Decreasing MgO corresponds with the
inception of ferrom agnesian m ineral fractionation, while the decreasing of AI2 O 3
and CaO are indicative of crystallization of pyroxene and plagioclase.

These

observations are in accord with experimentally predicted crystallization paths of
tholeiitic magmas (i.e., Ol: Ol + Cpx: (OI + ) C px+Pl: Pl + Cpx, etc) with a significant
initial stage of olivine fractionation.
Sun and Nesbitt (1978) suggested the use of Ca 0 /T i 0
versus Ti 0

2

plots to separate different magm a types.

A ^ C ^ /T iC ^ and Ca 0 /T i 0

2

and A ^ C ^ /T iC ^

2

Figure 7 shows the

plots of the rocks from the magmatic arc terrane (data

from Cudzilo, 1978) and northern passive margin terrane. The low-Ti calc-alkaline
rocks from the magmatic arc terrane have extremely high A ^ C ^ /T iC ^ and
CaO /TiC > 2 ratios whereas the relatively high-Ti tholeiitic basalts from the northern
passive margin terrane have lower A ^ O j/T iC ^ and Ca 0 /T i 0

2

ratios (less than

20). The ratios increase with increasing degree of source melting that results in a
progressive decrease of A ^ O j/T iC ^ and C aO /T iC ^ in the residual mantle. Sun
and Nesbitt (1978) noted that these ratios level off and rem ain constant at a critical
value, irrespective of the degree of melting.

The maximum ratios in magma

produced from the Mid-ocean ridges are close to those in chondrite (17 to 20) at
approximately 0.8 % TiC> 2 (G askarth and Parslow, 1987).

29

Thus, the high-ratios

Figure 6 . V ariation of major elem ents versus differentiation index (F eO /(F eO +
M gO)). Total Fe is reported as FeO. T he dashed line in the T i 0 2 vs.
F /F + M diagram marks the division betw een High-Ti tholeiites and
Low-Ti tholeiites proposed by Serri (1981). O pen circles with dots are
dikes, crosses are Hemlock volcanics, and triangles are Badwater
greenstones.

30

cu
o
UI

A 1 .0

60

50

cite-

40
co

2 0

15
o
<D
U_

10

1

0.4

0.5

0.6

0.7

F/F+M

0.8

0.4

0.5

0.6

0.7

F/F+M

0.8

0 .3

0.2

CaO

o
c
2E

+ +

0.1

0.0
CO

T

no

+
-

2

J9
0
(0

4- ©

0

%

>

*
o

’ ’+k A l %L e r ®.«*

0.4

0.5

0.6

0.7

F/F+M

+

0 .8

0.4

0.6

0.7

F/F+M

0.6

1

'

'

'

0.6

©
—

o

-

e

+

_

0.4

+;

/« * * * /

©
t

®
© ++A.
■fe
r

0.2

©
*

.

•
n ft

0.4

a s g fir *
*
— 1--------------1--------------1— ...

0.5

0.6

0.7

F/F+M

I

0.8

0.4

0.5

0.6

0.7

F/F+M

0.8

Figure 7. Diagrams using TiO ? to detect degree of depletion in the magma source
fSun and Nesbitt, i978). M ost of the rocks of Quinnesec Formation
(data from Cudzilo, 1978) reside in the area m arked for arc volcanism,
indicating they originated from partial melting of residual mantle. The
dikes, Hem lock volcanics, and Badwater greenstones, on the other
hand, came from a less depleted mantle source. Legend: open circle
with dots, dikes; triangles, Badwater greenstones; cross, Hemlock
volcanics; and diamonds, Quinnesec Formation.

34

~o

150

A1203/T102

SOURCE
DEPLETED

100

50

SOURCE RELATIVELY
UNOEPLETED

TiO

60

❖

Ca0/Ti02

SOURCE
DEPLETED

40

SOURCE RELATIVELY
UNDEPLETED

20
i
Uo

TiO.
35

could not be produced by an increasing degree of melting of any known mantle
mineralogy and the depletion must be inherited from the source.
origin suggested for these high-ratio low Ti 0

2

One possible

basalts is remelting of a source which

was severely depleted in incompatible elem ents by previous episodes of magma
extraction.
Thus, high-Ti basalts are possibly similar to Mid-ocean ridge type, whereas
low-Ti basalts are m ore analogous to m odem basalts from island arc or interarc
basin (Sun and Nesbitt, 1978; G askarth and Parslow, 1987). Based on Figure 7, it
can be suggested that the rocks of the northern passive margin terrane are similar to
high-Ti M ORB-like tholeiites derived from a relatively undepleted source(s).

2. Trace and rare earth elem ents

Trace elem ent behavior has been recognized as more sensitive to the process
of magma generation and differentiation in basaltic systems (Yoder, 1976).
Decoupling of trace elem ents from major elements contributes to this sensitivity.
Trace elem ents are not as intimately tied with the polymerization of the melt as are
the m ajor elements.

This results in a greater response of the trace elements to

change during magmatic processes.
V ariation of trace elem ents with increasing magmatic differentiation for the
rocks of the dike swarms, Hem lock volcanics, and Badwater greenstones are
indexed with mole percentage of F eO /(F eO + MgO) and are shown in Figure

8

.

Com patible elements, Ni and Cr, decrease with increasing differentiation, while the
hygromagmatophile elements (Rb, Ba, Zr, Y, etc.) show a trend of enrichm ent with
increasing differentiation.
It has been suggested that the elements such as Ti, P, Zr, Hf, Th, Cr, Ni, Sc,
Nb, Y, and H R E E in basalts are resistant to alteration and m etamorphism (Pearce

36

T ab le 3.

Average chemical compositions of the rock suites.
Dikes
(N = 44)

Hemlock volcanics
(N=40)

Mean

Range

C.V

Mean

Range

p2° 5

49.58
1.69
14.04
13.01
0.20
6.54
7.84
2.58
1.12
0.24

44.98-55.03
0.63- 2.83
12.44-17.33
9.30-16.67
0.13-0.26
2.46-11.64
3.39-11.28
1.46-4.48
0.31-2.26
0.04-1.33

4.1
37.9
8.6
14.5
14.7
30.1
26.7
29.0
43.9
117.4

50.36
1.46
14.55
11.86
0.18
6.33
8.00
2.88
0.90
0.16

45.34-60.02
0.84-2.62
11.82-18.17
6.56-14.66
0.08-0.22
2.25-10.72
3.17-11.00
1.28-5.52
0.12-2.84
0.06-0.43

Ni
Cu
Zn
Rb
Sr
Y
Zr
Nb
Ba
La
Ce
Sm
Eu
Tb
Yb
Lu
Hf
Th
Cr
Sc

81.1
80.9
107.4
31.2
218.1
26.7
138.2
17.1
393.3
20.84
40.62
5.15
2.03
0.801
2.44
0.403
4.51
6.72
182.9
36.98

0.0-440.3
7.5-228.4
57.2-165
1.6-101.4
62.7-516
14.9-55.3
50.1-288.5
2.8-68.7
18.6-2008
4.64-46.4
9.58-101.26
1.37-9.18
0.90-4.12
0.34-1.14
1.48-3.06
0.19-0.52
1.87-11.09
1.42-11.8
40.5-603
19.3-50.6

97.4
77.3
21.0
63.9
44.6
35.3
65.1
116.4
93.5
90.9
99.3
63.7
53.7
23.7
13.7
16.4
53.0
50.3
72.4
17.1

72.0
61.51
100.1
12.88
239.9
23.9
143.9
14.10
438
23.76
49.23
5.11
1.66
0.696
2.37
0.371
4.42
5.58
134.8
34.64

3.3-218.4
1.5-136.9
59.6-200.2
0.0-38.4
56.1-920.2
13.4-61.5
48.4-563.3
1.0-72.7
0-4145
4.0-187.9
18.29-275.2
1.00-24.78
0.81-5.28
0.32-1.15
1.47-15.13
0.17-0.71
1.47-15.13
0.83-46.84
5.1-490.9
15.8-52.9

SiO ,
Ti02
AljOs
FeO
MnO
MgO
CaO
Na20
KgO

C.V = Coefficient of Variation ([STDV./Mean] x 100)

Badwater greenstones
(N=29)
C.V

Mean

Range

C.V

7.1
35.9
10.9
17.5
17.1
32.5
26.8
34.7
75.6
■ 50.0

49.16
1.53
15.30
11.74
0.18
6.18
9.24
2.37
0.52
0.16

43.7-52.5
0.97-2.54
12.54-20.99
7.43-15.35
0.13-0.25
3.62-9.51
4.26-16.95
0.29-5.16
0.04-1.86
0.10-0.30

4.8
26.14
10.9
15.5
13.8
22.6
28.9
41.9
86.4
35.0

399
106.3
93.83
8.26
256.0
22.57
118.8
12.00
253.1
16.21
34.67
4.12
1.87
0.70
2.27
0.367
4.54
4.64
190.4
37.73

24.0-8609
0.1-248
62.20-127.60
0.00-37.80
115.3-524.0
17.4-34.2
78.20-210.9
4.00-25.8
30.4-1340
8.76-40.88
19.98-102.5
0.75-7.7
0.99-2.94
0.40-1.02
1.72-2.91
0.13-0.45
2.17-9.45
1.83-11.85
22.3-368.1
27.0-50.70

411
57.1
19.3
110.9
40.7
21.6
29.4
43.6
119.9
48.2
52.3
37.4
30.5
22.2
121.4
17.0
44.4
52.6
53.4
15.7

83.5
68.6
25.7
79.3
72.1
39.4
68.6
90.4
163.0
134.4
95.5
83.8
52.4
29.0
43.9
27.0
68.3
142.5
95.6
24.8

Figure

8

. V ariation of trace elem ents versus differentiation index (F eO /(F eO +
MgO)). Legends as in Figure 6 .

38

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10

and Cann, 1973; Floyd and W inchester, 1975; Wood et al., 1976; Condie et al., 1977;
Ludden and Thompson, 1978; Ludden et al., 1982), while other elements such as Sr,
Ca, Ba, K, and Na can be shown to be mobile even during low grade alteration
(H um phris and Thompson, 1978).

In this study, the LIL (large ion lithophile)

elem ents of the rock suites show a much wider scattering and poorer correlation as
com pared to the tight clustering of the immobile elem ents (e.g., Zr, Y).

This

suggests that the immobile elem ents can be used for modelling whereas the LIL,
whose scattering is problem due to alteration and metamorphism, may be used with
caution.
The R E E concentrations were normalized to chondrite values (Thompson,
1982) and then plotted logarithmically against atomic number. Plots of chondrite
normalized R E E data for the all rocks are shown in Figure 9 (dikes), Figure 10
(Hem lock volcanics), and Figure 11 (Badwater greenstones). Each figure is divided
into three groups depending on the F eO /(F eO + MgO) value: greater than 70,
betw een 60 and 70, and less than 60.

Averaged values for the complex are

illustrated in Figure 12. For comparison, analyses of crustal rocks (data from this
investigation and Ueng et al., 1988) sampled throughout the region are also
presented.

al Dike swarms: The chondrite normalized R E E patterns for the dike swarms are
essentially similar except for the LR EE depleted samples (Figure 9a).

The

unusually low LR EE concentrations and strong positive Eu anomaly patterns in
Figure 9a may be related to the high plagioclase phenocryst content in samples IP-4,
5, and NS-3 because plagioclase does not accommodate

Ti, P, and most R E E

except Eu in its structure (Philpotts and Schnetzler, 1968). The general pattern has
a relative LR EE enrichment, normal to slightly depleted Sm value, and normal
(Figure 9c) to slight enrichm ent of Eu in less evolved samples (Figure 9a,b).

43

Figure 9.

Chondrite norm alized R E E patterns of the dikes.
Samples are
subgrouped based on F eO /(F eO + MgO) <60 (a); 60 to 70 (b); and >
70(c).

44

Dikes/Chondrite

The porphyritic dikes o f suspected Archean age, show high contents of Ti 0
(2.12-3.53%), are
L R E E /H R E E

highly enriched

patterns

in incompatible

([L a/Y b]c = 10.25-22.68,

2

elements, and enriched

[C e/Y b]c = 10.87-14.8).

The

chemical compositions of the A rchean (?) dikes are listed in Table 4. These dikes
were probably generated from a different magma source from that of the
Precam brian X dikes based on the chemical compositions and conserved elements
ratio plot (Figure 15b). D ue to the ambiguity of the age of the dikes, these dikes
were excluded in this study.

b l H em lock volcanics: The chondrite normalized patterns for the Hemlock
volcanics have a slight enrichm ent of L R E E in less evolved samples (Figure 10a)
and progressively higher L R E E enrichm ent in the most evolved rock samples
(Figure 10c).

The Hem lock volcanics also show a small depletion of Sm and

enrichm ent of E u in less evolved rock samples, and normal to depleted distribution
of Eu in the most evolved rock samples.

cl Badwater greenstones: The chondrite normalized R E E patterns for the Badwater
greenstones (Figure 11) are very similar to the those of dikes and Hemlock
volcanics.
The R E E distribution patterns are similar within Figure 9, 10, and 11, with
increasing L R E E enrichm ent with increasing differentiation.

One of the less

evolved dike sample (NRP-3) has a high enrichm ent of LR EE compared to H R E E
([L a/L u]c = 15.9 and [C e/Y b]c = 10.3). This value is approximately twice as much
as that of normal continental tholeiites ([L a/L u]c = 0.5 to 7.6, Henderson, 1984).
The excessive amounts of L R E E in this less evolved sample cannot be explained by
either crystal fractionation or crustal assimilation.

This enrichment is possibly

caused by carbonization or chloritization (Condie et al., 1977). The Eu anomalies,

46

Table 4.
Comparision of chemical compositions between the Precambrian X dikes and the
Archean dikes.
Archean (?) Dikes
(N = 7)
Mean
Range

Precambrian X Dikes
(N=44)
Mean
Ranae

P2 O5

52.58
2.72
14.35
15.49
0.23
3.58
5.15
2.70
2.38
0.80

49.95-55.73 49.58
2.16- 3.65
1.69
12.65-15.52 14.04
12.31-17.57 13.01
0.17- 0.28
0 .2 0
2.52- 5.35
6.54
7.84
3.57- 7.84
0.38-4.11
2.58
1.29- 5.07
1.12
0.26-1.35
0.24

44.98-55.03
0.63- 2.83
12.44-17.33
9.30-16.67
0.13- 0.26
2.46-11.64
3.39-11.28
1.46- 4.48
0.31-2.26
0.04-1.33

Ni
Cu
Zn
Rb
Sr
Y
Zr
Nb
Ba
La
Ce
Sm
Eu
Tb
Yb
Lu
Hf
Th
Cr
Sc

5.5
17.9
146.4
53.2
236.7
44.4
138.2
58.5
926.4
62.28
132.3
11.90
4.16
0.87
2.51
0.40
7.11
9.49
74.9
29.37

0 .0 -3 1 .8
7.5 - 52.7
112.6-183.0
13.1 -101.4
62.7 -379.1
35.6 - 54.5
50.1 -439.0
29.3 - 84.4
123.6-2130
39.51-87.11
110.4-174.5
8.03-16.19
2.69- 6.07
0.71- 1.04
2.08- 2.85
0.34- 0.46
3.72-14.10
5.61-11.70
43.8 - 96.7
19.30- 37.60

0.0 -430.3
7.5 -228.4
57.2-165.0
1 .6 -7 9 .6
62.7-516.0
14.9 - 55.3
50.1 -288.5
2.8 - 68.7
18.6-2008
4.64- 46.4
9.58-101.26
1.37- 9.18
0.90- 4.12
0.34- 1.14
1.48- 3.06
0.19- 0.52
1.87-11.09
1.42-11.80
40.5 -603.0
19.30- 50.60

SiOo
TiOo
AI0 U 3
FeD
MnO
MgO
CaO
Na?0
KpO

81.1

80.9
107.4
31.2
218.1
26.7
138.2
17.1
393.3
20.84
40.62
5.15
2.03
0.80
2.44
0.40
4.51
6.72
182.9
36.98

47

Figure 10.

Chondrite normalized R E E patterns of the Hem lock Volcanics.
Samples are subgrouped based on F eO /(F eO + MgO) < 60 (a); 60 to
70 (b); and > 70 (c).

48

Hemlock/Chcmdrite

100

o
o

o
o

r rin i

r m

Ls
Ce
Sm
Eu
Tb
Yb
Lu
.........................................

Figure 11.

Chondrite norm alized R E E patterns of the Badw ater greenstones.
Samples are subgrouped based on F e O / (FeO + M gO) < 60 (a); 60 to
70 (b); and > 70 (c).

50

Badwater/Chondrite

positive anom alies in less evolved rocks and flat to negative anom alies in more
evolved rocks, can be reasonably explained by crystal fractionation of plagioclase,
which preferentially deprives the m elt of E u under favorable oxygen fugacity
conditions.
Figure 12 shows the average R E E patterns of the dike swarms, the Hem lock
volcanics, and th e Badw ater greenstones.

These groups show very similar R E E

p attern and all exhibit L R E E enrichm ent (e.g.,: [C e/Y b]c = 0.99 - 9.38 and
[E u/Sm ]c = 0.48 - 1.82). T he similar R E E patterns of these rock suites may reflect
sim ilar events during m agm a generation a n d /o r similar source rocks in early
Proterozoic time. This possibility will be examined later.
Spider diagram s for averages of the dike swarms, Hem lock volcanics,
Badw ater greenstones, and regional crustal rocks are shown in Figure 13. These
igneous groups show enrichm ent of the LIL

elem ents relative to the other

incom patible elem ents. A noteworthy feature is the m arked relative depletion in
Nb.

These hygromagmatophile elem ent patterns are very distinct from those of

m odem alkali basalts, which are enriched in Nb, and M ORB, but closely
com parable to E-type M ORB, which is enriched in incom patible elem ents and
L R E E relative to H R E E .

52

Figure 12.

Chondrite norm alized R E E patterns of the averages of the dikes,
Hem lock volcanics, Badw ater greenstones, and regional crustal rocks.
D ata source for crustal rocks cited in U eng et al. (1988).

53

AVERAGE
200

OF
i—

i — i— r

THE

ROCK

GROUPS

i—

i—

i—

i—

r

I

1------1—

i

i

i

i

L

I

I

cn

1 ___ 1___ I___ L

La Ce

i

j

i

Sm Eu

Tb

L_

Yb Lu

□
O
A
*

DIKES
HEMLOCK VOLCANICS
B.W. GREENSTONES
CRUSTAL ROCKS

Figure 13.

Chondrite norm alized geochem ical patterns for the averages of the
dikes, H em lock volcanics, and Badw ater greenstones. F or comparison,
averaged crustal rocks are presented (data from U eng et al., 1988).
Norm alizing factors and arrangem ent of elem ents are based on
Thom pson (1982).

55

AVERAGE
800

1

1 — i

i

OF

THE

ROCK

GROUPS

1

1

1

1

1

1

1

!

1

1

1

1

1

1—

i— i

i

i

i

i

i

i

i

i

i

i

i

i

»

BaRbTh K NbTaLaCeSr P SmZrHf TiTb Y Yb

m
O
A
*

DIKES
HEMLOCK VOLCANICS
B.W. GREENSTONES
CRUSTAL ROCKS

DISCUSSION

1. Com agm atism
T he relationship of the m agmatic origin betw een the dike swarms and the
volcanic piles (Hem lock volcanics and Badw ater greenstones) has

rem ained an

unsolved problem . As a result of this investigation, these rock suites are thought to
be comagmatic for the following reasons. These rocks contain the sam e phenocryst
assemblages and exhibit a narrow range of whole rock chemistry (see Appendix 2).
Also, according to their chemical characteristics, these rocks show parallel
elem ental variation trends (Figures
patterns (Figure

1 2

6

and

8

), very sim ilar R E E /ch o n d rite plot

), and com parable elem ental abundances in spider plots (Figure

13).
Russell and Nicholls (1988) applied Pearce (1968) m ethods to provide
unam biguous tests of petrologic hypotheses. Commonly, the physical and chemical
differentiation of magmas occurs through the crystallization and separation of
minerals, in which case the behavior of elem ents during differentiation is a direct
reflection of the stoichiometry of the m ineral involved.

For instance, in some

magm atic systems we can recognize elem ents whose absolute am ounts are affected
by the differentiation process, and other elem ents (i. e., "conserved elements") which
are not affected by the process (Nicholls, 1988).

W hen one or m ore conserved

elem ents exist in a system, it is possible to analyze the compositional data with
Pearce elem ent ratio diagrams (Stanley and Russell, 1987).

In basaltic rocks,

diagrams of T i/K vs P /K can provide a test of the comagmatic hypothesis (Russell
and Nicholls, 1988). Because these elem ents rem ain incompatible with respect to
differentiation, the ratios that are comprised of conserved elem ents rem ain constant
throughout the process, so comagmatic rocks should define a tight cluster.

57

Figure 14a is a conserved elem ents plot of P /K vs T i/K for the dike swarms,
th e H em lock volcanics, and the Badw ater greenstones. If all basalts are derived
from the sam e magma, the d ata should plot within the variance range which can be
attributed to analytical uncertainty. However, Figure 14a shows at least two distinct
groups (G roup I and G roup II).

G roup I is com posed of the dike swarms, the

H em lock volcanics, and some Badw ater greenstone samples, while group II is
com posed of Badw ater greenstone samples with low K 2 O contents.

Figure 14a

illustrates that th e scatter in the dike swarm and H em lock volcanics data sets (in
G roup I) is sm aller than the two standard deviation error bars due to analytical
error.

Thus, there is no reason to reject the hypotheses that dike swarms and

H em lock volcanics are comagmatic. The group II rocks can be interpreted to m ean
th at these low K 2 O lavas were derived from a different source or form ed by a
different processes than the group I basalts.
T here are two possible ways to explain the magmatic relationship betw een
the Badw ater greenstones and other rock suites.

The first possibility is that the

Badw ater greenstones w ere generated from a different magma source.

In other

words, Badw ater greenstone represents a piece of M ORB independent of the
passive margin terrane which was accreted onto the early Proterozoic continents as
proposed by Larue (1983). However, several problem s arise with this model. The
Badw ater greenstones show relative enrichm ent of L R E E com pared to M ORBs and
show a Nb depletion which is a typical characteristic of continental tholeiites. The
other problem is that the K 2 O content of the Badw ater greenstones is much higher
than th at of M ORBs.

Figure 15a shows a conserved elem ents ratio plot of the

Badw ater greenstones and M ORBs from different oceanic suites (see Table 5).
T here is no reasonable explanation for the enrichm ent of K 2 O in the Badwater
greenstones (average = 0.52 %) as com pared to the MORBs. The P-type M ORB
(the so-called "plume" or enriched type) shows com parable ratios of T i/K and P/K .

58

Figure 14.

a) Conserved elem ent plot using P /K and T i/P for the dikes, the
H em lock volcanics, and the Badw ater greenstones. T he two standard
deviation erro r bars result from analytical uncertainty, b) Conserved
elem ent plot using P /Z r and T i/Z r for the studied rock suites. Legend:
stars, dikes; triangles, Badw ater greenstones; cubes, H em lock volcanics.

59

m
2 .0

S td .

E rror

Dikes
a B.W. Greenstones
0 Hemlock Volcanics

'A '

Oev.

Bounds

*/
/
* A

/* /)

/
/

/

/

A

/ e a
I f f A JS
-•V V ^

Group II
/

/ K#S, ' I

Group I

i

0. 8
P/K

MPR

1. 6

0 .0 200

I

I

1 —1— 1 1 1

& Pikes
& Badwater

1 T

1 l 1— 1
S t d . Dev.
E rror Bounds

□ Hemlock

T i/Z r

0.0150

0 .0 100

-

0.0050

-

L. J__1 ..1

•2.0 -1.0

1 1

0

i

i

i

i

i

i

i

1.0 2.0 3.0 4.0 5.0

100

X P/Zr

TABLE 5.

A verages of m ajor elem ent compositions of M O R B from different localities.

1

Engel
e ta l.

easa

SiO?
TiOh
A12 0 *
F eO
M nO
M gO
CaO
N a20
K?0
P J05

49.93
1.51
17.25
8.71
0.17
7.28
11.86
2.76
0.16
0.16

2
M elson
T hom pson
(1971)

3
Pearce
(1976)

4
V iereck
et al.
(in press)

5
LeRoex
et al.
(1983)

49.61
I.43
15.81
9.18
0.16
8.53
II.1 4
2.71
0.26
0.15

49.21
1.42
16.09
10.17
----7.69
11.34
2.80
0.24
0.15

50.26
1.10
15.80
9.40
0.17
7.84
12.43
2.13
0.24
0.09

49.33
3.03
15.09
11.17
0.18
6.40
8.92
3.45
1.18
0.53

1. Average of A tlantic and Pacific O cean tholeiites.
2. Average M id-Atlantic Ridge basalts.
3. Average for ocean-floor basalts.
4. Average of M id-A tlantic Ridge basalts. Sampling location is bounded by 40 N
and 30 N and by 40 W and 30 W.
5. Average of P-type M O RBs from the Southwest Indian Ridge.

62

However, with regard to trace elem ent characteristics such as N b depletion and
Y /N b ratio (P-type M O RB < 1), the Badw ater greenstone can not be a piece of Ptype M ORB. Thus, for these reasons, the proposal of L arue (1983) is rejected .
A nother possibility, favored in this investigation, is th at the all rock suites are
comagmatic. Im plicit to this argum ent is that certain rocks (e.g. G roup II) were
affected by seaw ater infilteration m etasom atic processes. Chem ical characteristics
of Badw ater greenstones based on major, trace elem ents and R E E show no
distinguishable difference (except K 2 O ) with those of dike swarms and the Hem lock
volcanics. T he wide scattering of d ata sets in the T i/K vs. P /K plot (Figure 14a) is
caused by low concentrations o f ICjQ of group II samples (0.04-0.26%) com pared to
that of group I sam ples (Table 6 .). O f particular significance to this argum ent is the
m etam orphic alteration of pillow basalts by reaction to sea water. T he interaction
with sea w ater depends mainly on the geotherm al gradient and P j-i2 0

The

principal factors which control the sea w ater m etasom atic processes are the
penetration of w ater along concentric and radial joints produced in lavas by abrupt
cooling, hydration, oxidation and m atter exchange, which is the leaching of MgO
and K 2 O and enrichm ent in Fe, V, Cs and other elem ents derived from sea w ater
(G elinas et al., 1982; Ludden et al., 1982). W olery and Sleep (1976) also suggest
th at intensive hydrotherm al reaction with hot sea w ater produces the change in
chemical trend (loss of K and gain of N a and H 2 O). T he experim ental study of
H um phris and Thom pson (1978) shows that basalts from the M id-Atlantic ridge that
are converted to chlorite and epidote rocks contain relics of their original
com position in the centers of the samples.
Thin section study of the group II samples of the Badw ater greenstone
revealed th at the rocks have higher contents of epidote and clinozoisite phenocrysts
as com pared to the group I samples, with a chloritic matrix with very fine grains of
epidote or clinozoisite. Also, chemical characteristics for the epidotized m etabasalts

63

Table 6.

Com parison of averaged MgO, N a 2

0

, CaO, and K 2 O abundances betw een the

group I and group II samples.

G roup I (N = 9)

G roup II (N = 6 )

M gO

5.57

5.42

N a20

2.80

1.88

C aO

8.14

10.28

K jQ ______________ 0 7 6 ______________________01Q_________
* sam ples with F / F + M values betw een

6 8

_________ G roup I ( N = 4)

and 72.

G roup II (N = 2)

M gO

8.19

7.74

N a20

2.52

1.85

C aO

10.09

11.76

KgQ______________ 04 3 ______________________ 023_________
* samples with F /F + M values betw een 55 and 58.

64

show low m agnesium, sodium and potassium contents and a relatively high calcium
content (Borg and M aiden, 1987). Table

6

gives calculated m eans of MgO, N a 2

0

,

K 2 O, and C aO for the group I and group II rocks. In this table, group II samples
show relatively low contents o f MgO, N a 2

0

, and K2 O while higher content of CaO

com pare to the group I samples.
T he m ineral assemblage and chemical compositions suggest that the group II
rocks suffered alteration due to hydrotherm al reaction with sea water. This process
resulted in the depletion of K 2 O to varying degrees depending on the intensity of
the reaction.

Figure 14b shows conserved elem ents ratios plot using Z r as

denom inator. It has been recognized that the Z r is an immobile elem ent during sea
w ater alteration process. This Figure confirms the hypotheses that the group I and
group II rocks w ere generated from same magm a source.

65

Figure 15. a) Conserved elem ent plot using P /K and T i/K for the calculated means
from the dikes, the H em lock volcanics, the Badw ater greenstones, and
M ORBs from different areas (locations are listed in T able 3). b)
Conserved elem ent plot for the calculated m eans from the dikes, the
H em lock volcanics, the Badw ater greenstones, and the A rchean (?)
dikes.

66

8

X
A
□
o
4X
<*>
$

T

oc 5
<T>

CL

X
❖

ap
i.

- 1

-

0.1

0. 2
P/K

0.5
MPR

Dikes
B.W. Greenstones
Hemlock Volcanics
MORB 1
MORB 2
MORB 3
MORB 4
MORB 5 (P-type)

0.0125

•

"T”

■

I

-

•

r. . . “

Std. Dev.
Error Bounds
—

-

cr>

T i/Z r

00

▲

0.0075

m

*

-

❖

i

0.0025
0

i

-

i

i

0.00 1
0.00 2
P/Zr

i
0.(

# Dikes

0 Hemlock
a Badwater
❖ Archean (?) Dikes

2. Chem ical variation of the evolved rocks

The chemical differentiation of m ost magmas results from processes
operating in the subsurface.

Factors controlling their com position include the

source com position as well as pressure, tem perature, and degree of partial melting
of the source. Fractional crystallization and contam ination or mixing may operate
at any level to produce further variation.
T he evaluation of fractional crystallization is best perform ed on fresh rocks
for which original m ineral compositions are available.

Because of the alteration

process, no original m ineral d ata are available for these rocks. Thus, alternative
schemes w ere used. Russell and Nicholls (1988) proposed a m ethod which can be
used to illustrate the causes of chemical diversity in com agm atic suites, using Pearce
elem ent ratio plots. However, this m ethod was originally devised for fresh volcanic
rocks. It thus appears that careful consideration of chemical changes induced by
m etam orphism is needed before applying this m ethod to the m etabasalts.

It has

been reported by a num ber of authors (e.g., Beswick and Soucie, 1978; Colley and
W estra, 1987) that Na 2

0

, K^O, and CaO are commonly mobile during alteration

and m etam orphism . Gelinas et al. (1982) show that Si0
immobile and MgO, FeO, and Na 2
and alteration.

0

2

and AI2 O 3 are relatively

are mobile com ponents during m etam orphism

Therefore, use of these plots is valid, so long as the constraints

im posed by alteration and m etam orphic effects can be evaluated.

Figure 16

presents simplified models of alteration and m etam orphism which affect the slope
and intercepts of the Pearce ratio plots. Note that if alteration or m etam orphic
effects are constant for all rocks, these effects do not change the slope of trend, but
change the intercept of the variation line (Figure 16a, b, c).
A bsolute changes in chemical compositions during alteration an d /o r
m etam orphism are difficult to evaluate. However, if we assume changes of up to 10

69

Figure 16. Simplified m olecular proportion ratio plot (oxides X, Y, and Z ) showing
changes of the slope and intercept of original trends due to alteration
o r m etam orphism .

70

✓> b
/ '/ / / *
/ / /
/ / /
* * //

Y /Z

I

Constant increase of Y component (a',b')
and decrease of Y component (a",b'j

^

x/z

A
M

Constant increase of X component (a',b')
and decrease of X component (a",b'j

/ / /
/ / /
« a’ ,
a a

Y /Z
a

x/z

B
°

^t}
✓✓
/ /u b
b
Constant increase of X, Y component (a',b')
and decrease of X, Y component (a",b”)

Y /Z

*a"

x/z

fC

b
mi ®
.in
b» ' b^,«b
/ / / '
/ / / '* &

Y /Z
a

x/z

Either increase or decrease of only one
end member. Increase or decrease of
X component (a,b"' and a,b"") increase
or decrease of Y component (a,b' and a,b")
for ± 1 0 % change, the maximum slope
change is ± 0 . 1 .

D

71

% for a com ponent, a slope change of approximately + 0 .1 results (Figure 16d). It
is therefore suggested that the alteration and m etam orphic effects on the m ineral
chemistry are much sm aller than th at of fractional crystallization which reflects the
stoichiom etry of the m ineral involved. Com positional variations induced by these
processes will not critically change the slope of the trend, thus the slope of the plot
is mainly controlled by fractional crystallization.
T he chemical diversity of the dikes and the volcanic rocks is presented in
Figure 17, which is a Pearce elem ent ratio diagram with the axes Y = 0.5(Mg + F e )/K
and X = S i/K (and X = S i/Z r). The key attribute of this diagram is that all ferrom agnesian silicates that crystallize from basaltic m agm a have a unique slope.
Chem ical compositions that are related solely by the addition or subtraction of
olivine will define a slope of 1.0. The addition of any other phases that contain Mg,
Fe, or Si will cause the data to deviate from this slope of 1.0 (e.g., slopes for
plagioclase and augite fractionation are 0.0 and 0.25 respectively; Russell and
Nicholls, 1988). The d ata (dikes, Hemlock volcanics, and Badw ater greenstones)
describe a linear trend with a little scatter, which is probably due to alteration
a n d /o r m etam orphic effects.
The slope best fit by the data (0.285) is much less than 1.0, which implies the
fractionation mostly of augite and plagioclase, with olivine only as a m inor phase.
Figure 18 is a series of Pearce elem ent ratio plots whose axes are form ulated to test
specific m ineral assemblages concerning the differentiation of the basaltic rocks
(Russell and Nicholls, 1988). The axes for the diagrams in Figure 18 are chosen so
that rock compositions related by the sorting of olivine + plagioclase (Figure 18a),
olivine + augite (Figure 18b), and olivine + augite + plagioclase (Figure 18c) will
define a trend with a slope of 1.0 (Stanley and Russell, 1988). Each figure shows
relatively good correlation, however, in both Figure 18a and Figure 18b the
calculated slope of the best fit lines are significantly different from the expected

72

TABLE 7

Table 7a. Summary o f Pearce elem ent ratios used in the evaluation of petrologic
hypotheses. E lem ent n is a conserved constituent (Russell and
Nicholls, 1988).
PH A SE(s)

X /n

Y /n

Predicted
Slope

OL

0.5 (M g + Fe)

S i/n

O L = 1.0

PL

2N a + Al

S i/n

PL = 1.0

AU

2Ca + N a - Al

S i/n

A U = 1.0

O L+A U

0.5 (M g + F e)+ 1.5Ca

S i/n

O L + A U = 1.0

O L+PL

0.5(M g+ Fe) + 2 N a+ Al

S i/n

O L + P L = 1.0

S i/n

O L + P L + A U =1.0

O L + P L + A U 0.5(M g+ Fe) + 1.5Ca
+ 2.75Na+0.25Al

Table 7b. Slopes and intercepts of the investigated rock suites for Pearce elem ent
ratio plots.
PH A SE(s)

X /n

M easured Slope

OL

0.5(Mg + Fe)

S i/K
S i/Z r

0.2795
0.2850

O L+A U

0 .5(M g+ F e)+ 1.5Ca

S i/K
S i/Z r

0.7971
0.6835

S i/K
S i/Z r

0.7581
0.8125

S i/K
S i/Z r

1.077
1.044

O L+PL

0.5(M g+F e) + 2 N a+ A l

O L + P L + A U 0 .5(M g+ F e)+ 1.5Ca
______________ + 2.75N a+0.25A l

73

Figure 17. T h e dikes, H em lock volcanics, and Badw ater greenstone data are plotted
in th e Pearce elem ent ratio diagram Y = 0.5 (Mg + Fe) / K and X =
S i / K (17a), and Z r as denom inator (17b). The rock chemistry defines
a straight line trend, however, the slopes are inconsistent with olivine
fractional crystallization.

74

90
N
O)
SI

60

in
o

+

OJ

30
^ Dikes
^ Badwater
□ Hemlock

Ll .

in
0

-30
-70

130
Si/K

0.20
S lo p e -0 .2 8 5 0

M

cn

s 0. 10

in

•

o
Ll_

in
o

-0.2

0

0.2
0.4
Si/Zr

230

330

Figure 18. Pearce elem ent m olecular proportion ratio plots to test differentiation in
basaltic rocks for specific m ineral assemblages, a) test for olivine and
augite fractionation, b) test for olivine and plagioclase fractionation
c)test for olivine, plagioclase, and augite fractionation at the 95%
confidence level.

76

0.5Fe+0.5Mg + l.5Ca/K

200

S lo p e -O .7971

150

&

50

Dikes
a Badwater
□ Hemlock

0

-50
-70

30

130
Si/K

230

330

.5 (Fe+Mg)+1.5Ca/Zr

.5
S lo p e -0 .6 8 3 5

.3

1

-0.2

0

0.2
0.4
Si/Zr
77

0.6

0.8

Al+0.5Fe+0.5Mg+2Na/K

330
S lo p e -0 .7 5 8 1

230

130
Dikes
Badwater
Hemlock

30

-70
-70

130
Si/K

330

230

Al+0.5 (Fe+Mg)+2Na/Zr

.5
S lo p e -0 .8 1 2 5

.3

.1

0.2

0

0.2
0.4
Si/Zr

0.6

0.8

0 . 25A 1+0.5 (Fe+Mg) + 1 .5Ca+2.75Na/Zr

0.25A 1+0.5

(Fe+Mg) + 1 . 5 C a + 2 . 7 5 N a /K

370

270

170

70

0.2

Dikes
Badwater
Hemlock

-70
130
Si/K

0

0.2
0.4
Si/Zr

230
330

6

4

2

0

0.6

0.8

slope of 1.0 (see Table 7). T he calculated slope of the lines in Figure 18c are 1.077
(K as denom inator) and 1.004 (Z r as denom inator) which are very close to 1.0.
These show that the chemical diversities in the dikes and the volcanic rocks are
mostly controlled by fractional crystallization of olivine, augite, and plagioclase.

80

3. Assessment o f crustal contamination

The problem of crustal contam ination of the basaltic m agm a during
em placem ent has been the subject of considerable debate. This problem has been
discussed by several authors with respect to wallrock assim ilation and fractional
crystallization (Bowen, 1928; Taylor, 1980). These authors point out that although
these processes are often tre ated separately, heat-balance considerations suggest
that the two should be coupled. H eat required for assim ilation can be provided by
the latent heat of crystallization of m agm a (D ePaolo, 1981).

Evaluation of the

C e /Y b vs. Ce plot (Figure 20) tends to support the assimilation-fractional
crystallization (ACF) model.

Figure 19a and 19b show the Rayleigh fractional

crystallization (FC; Allegre and M inster, 1978) and A FC (DePaolo, 1981) trends on
a C e /Y b vs. Ce plot. C e /Y b vs. Ce has the advantage of using elem ents for which
the analytical d ata are precise and for which the partition coefficients for m ineral in
basaltic systems are well known. The partition coefficients of these elem ents are
based on previously published d ata (Table 8 ).

Table 8 .
Partition coefficients of C e and Yb to olivine, clinopyroxene, and plagioclase.
OL*

CPX*

PL**

Ce

0.0033

0.166

0.14

Yb

0.0202

1.01

0.07

*: Frey et al. (1978)
**: H enderson (1984)

81

Figure 19. C e /Y b vs. Ce ppm plots, a) FC (Allegre and M inster, 1978) trends of
olivine, clinopyroxene, plagioclase, clinopyroxene : plagioclase (70:30),
and clinopyroxene : plagioclase (60:40). b) A FC (D ePaolo, 1981)
trends of olivine : clinopyroxene : plagioclase (5:60:35) for R = 0.35 and
R = 0.45. Com position of IP-5 (dike) is used as parental m aterial
because it shows high Mg num ber and least differentiated in R E E.
Partition coefficients for the m inerals are listed in T able 6 . R
represents assim ilation ratio.

82

50

FC p a t h s
40

Ce/Yb

Clinopyroxene
90%

30

20

cp x :p l -0.7:

80%
70

o.3_

90%
CPX: PL-0.65: 0.35-

80%
90%

1 0

80%
SO*

Olivine
Plagioclase
90%

0

0

20

40

60

Ce

80

100

120

ppm

50

AFC pat hs

Ce/ Yb

40

30
OL: CPX: PL-Q.05: 0.6: 0.35
(R-0.45)
50X

20

60%

70%

40%
30%

10

40%

60%
OL: CPX: PL-0.05: 0.6: 0.35
(H-0.35)

0

0

20

40

60

Ce
83

ppm

80

100

120

Figure 20.

C e /Y b vs. C e ppm plot for the dikes, th e H em lock volcanics, and
Badw ater greenstones with FC and A F C models.

84

50

i "i 1i

|

i

i

i

|

i""r*..rM
"|

i

i

i

|

r*'i... |

i

* Dikes
^ Badwater
□ Hemlock

i

*

40

AFC

03

Ce/Yb

i

30
20
%

10

u— i__L

-I

20

L.

I 1 • ‘ * I » « I ■ » « I 1 I

40

60

Ce p p m

80

100

L

120

O ne dike sam ple (IP-5) is chosen to approximate the starting composition
because of the following reasons; the low silica content (47%), high Mg value (63.4),
high content o f com patible elem ents (e.g., N i=220 ppm, C r= 427 ppm), and the
least differentiated R E E compositions. As shown by FC paths shown in Figure 19a,
differentiation by fractional crystallization alone seems to have difficulty evolving
the observed C e /Y b ratios and the Ce content present in the rocks before m ajor
portions o f the magm a solidified.

The continental crust (Ce = 60.0, Y b= 3,

H enderson, 1984) and supracrustal rocks (Ce = 61.25, Yb = 1.9, U eng et al., 1988)
have a higher Ce content and C e/Y b ratios.

It thus appears that the preferred

m odel to explain the excessive enrichm ent of Ce in the present study is ACF model
proposed by D ePaolo (1981). T he equation is:
Cm/ C ^ = F 'z + (r/r-1 ) * c j( 7 .c ° m ) * (1 -F 2)
Z = ( r + D - l) /( r - l)
Cm : C oncentration of the elem ent in the magma
Cj£ : Initial concentration of the elem ent in the magma
D : Bulk distribution coefficient
Ca : Elem ental concentration in the wall rock
r : Assimilation rate.
The results of the A CF trends are shown in Figure 19b. The trend of differentiation
can be interpreted to represent AFC rather than simple fractional crystallization.
O ther supporting evidence can be shown on the Z r/Y vs Z r plot (Figure 26). The
Z r/Y ratio for the supracrustal rocks, which is greater than 10 (Ueng et al., 1988), is
much higher than the m ore primitive flows and dikes.

Evolved rocks with

progressively higher Z r/Y ratios may have resulted from assimilation during
em placem ent of magmas.
In spider plots (Figure 13) of suite averages, the dike swarms, Hemlock
volcanics, and Badw ater greenstones are distinctively depleted in Nb with respect to

86

its neighboring elem ents. This depletion would require a m ineral that selectively
rem oves Nb with respect to other incom patible elem ents such as Th and La.
Although Nb partitions strongly into the Ti-rich m inerals such as sphene and rutile
(G reen and Pearson, 1987), there is no correlation betw een calculated Nb values
((N b)c - [(Th)c + (La)c]/2 ) and Ti content. Therefore, the depletion of Nb reflects
the contam ination of the m agm a by Nb depleted crustal m aterial. T he reason for
the depletion of Nb in continental crust has not been known. Recently H ofm ann
(1988) explained the Nb depletion by a switching of their compatibility during the
form ation of continental and oceanic crust. Nb was m oderately incom patible during
the form ation of the continental crust (similar to Ce) and becom es highly
incom patible (similar to U and K) during the form ation of M O RB (Hofm ann,
1988). N b # (Figure 21) values for the dike swarms, the Hem lock volcanics and the
Badw ater greenstones decrease with increasing differentiation index. This implies
continuing assimilation throughout the differentiation history. Some dike samples
show a horizontal p attern with increasing differentiation index. This distinguishing
pattern of the dikes may explained by early m ajor contam ination of a magma by Nb
depleted crustal com ponent, followed by less contam inated but increasing evolved
magmas.
Therefore, the crustal contam ination seems to have occurred during
em placem ent of magm a at depth, where tem perature difference betw een magma
and country rock is less, and fractional crystallization provided the characteristic
chemical signature of these rocks. This signature was modified locally at contact
margins, in the case of intrusive rocks, during solidification.

87

Figure 21.

Plots of N b # vs. m afic index ( F /F + M ) for the dikes, the Hem lock
volcanics, and th e Badw ater greenstones. N b # is defined as the
difference betw een chondrite norm alized Nb abundance and the
average o f chondrite norm alized Th and La. N b # = Nbcuon. O ^chon- + ^ c h o n - ) / 2 (U eng et al., 1988).

88

BADWATER GREENSTONES
o

Nb#

-5 0

-1 0 0

-1 5 0
0 .5

0 .6

0 .7

0 .8

F e O / (FeO + MgO)
HEMLOCK VOLCANICS
o

Nb#

-5 0
E3

□

-1 0 0

-1 5 0
0 .5

0 .6

0 .7

0 .8

F e O / (FeO + MgO)
DIKES
o

Nb#

-5 0

-100

-150
0 .5

0 .6

0 .7

F e O / (FeO + MgO)

0 .8

4. M agm a source

Som e continental tholeiites have relatively high and variable contents of
incom patible elements. Although several processes such as crustal contam ination,
and m elting o f enriched m antle source have been invoked, the cause of this
enrichm ent and variation are not well understood. In this investigation, rare earth
elem ent abundances were considered in an attem pt to m onitor m agm a source
com positions o f the studied rock suites.

In order to accomplish this goal, the

following procedures were perform ed.
A ) Initial m antle R E E abundances were sim ulated by the m ethod of Clague and
Frey (1982).
B) "Primitive liquid" com position was estim ated from the least evolved rock sample
(i.e., high Mg num ber and Ni, C r contents, low S1 O 2 ) by back calculation to a Mgvalue of

6 8

.

C) "Primitive liquid" is generated by partial melting of the source which has not
undergone modification. Thus, the calculated m antle composition was tested by
partial m elting models for their ability to account for the R E E contents of the
primitive liquid.

A) Initial m antle composition was sim ulated by the m ethod of Clague and Frey
(1982) which constrains the initial m antle composition using the m odal melting
equation (1) developed by Shaw (1970).

(T =
0

D

+ F ( 1 - P)

( E q ' 1}

0

C: elem ent concentration ( subscript o is initial, ^ is in liquid)
F: the degree of melting;

90

D: th e initial bulk partition coefficient;
P; p l* D l + p2*D2 + ... + pn*Dn, where p ’s are the fraction of total liquid
contributed by each phase during melting.

F or two elem ents X and Y, the elem ent concentration ratio

/C y is obtained from

equation ( 1 ) by dividing so th at result is a linear equation,
0y . „x

e
c[»

- ^ .L .

0

0 (i - px>
„ cx (i - p1')
------------------*---------------- cl + ~?------------ r ~
cy
cy (i - px)

(Eq- 2)

Cq ( 1 - Py )
E quation (2) represents the linear trend and has a intercept Bx = —
% ( 1 - PX)
W ith this intercept, we can calculate the elem ent abundance ratios of the initial
m antle by the following procedure: Intercept B x (Eq. 3) can be defined for the two
elem ents X and Y, and intercept Bz (Eq. 4) can be obtained for the two elem ents Z
and Y.
Cx ( i - p y )
B
= JLr
L
x
cy (1 _ p x }

v
Cz (1 - Py )
B
- -2- - - - - - r
z
Cy ( 1 - PZ )

(Eq. 3)

(Eq. 4)

F rom equations (3) and (4), the initial m antle elem ent abundant ratio can
calculated.
CX
CZ

B ( 1 - Px )
_x
Bz ( l - PZ )

( Eq.

5)

Figure 22 shows the linear differentiation trends of the studied rock suites
with Th as elem ent Y. From the intercepts of the linear trends, we can calculate the
R E E abundance ratios. T he approxim ate R E E concentrations in the initial mantle
was calculated using enrichm ent ratios relative to Yb. Although m antle peridotites
exposed in the crust (e.g., ultram afic inclusions in alkali basalts, alpine peridotites,
and peridotite m em bers of ophiolite sequences) range widely in composition,

91

Figure 22. T h /L a vs. Th, T h /C e vs.Th, T h /S m vs.Th, and T h /Y b vs. T h plots for
dikes, H em lock volcanics, and Badw ater greenstones.

92

£6

Th/La

Th/Sm
o

ro

-b.

cn

c
d

o

o

o

o

O

O

O

w

uj

cn

id

ro

lj

cn

cn

10

ID

ro

ro

Th/Ce

Th/Yh
o

o

—I cn
ZJ
ID

ro

»-»■

ro

uj

.u.

cn

o

o
ro

o
-tk

o
cn

o

cn

L
D

>-»■

ro

>

0 3

CD
CD
a
X
0)
ft
ro
“3

X
ro
3
O
n

7T

o
7T
ro
U)

H R E E show relatively uniform contents (about 2 to 4 tim es ordinary chondrite Frey e t al., 1978; Cleague and Frey, 1982; Frey, 1984).

Thus, it is possible to

constrain the approxim ate R E E content in the source m aterial using the Yb
chondrite value (0.2 ppm, H enderson, 1984). T he chondrite norm alized abundances
o f the source m aterial shows a relative enrichm ent of L R E E com pare to the H R E E
([L a/Y b]c =2.4, [C e/Y b]c =3.5, and [Sm /Y b]c = 1.2).

However, these enrichm ent

ratios are significantly lower th an the that of the m antle source for alkali basalt,
which has a [L a/Y b]c of 5.3 to 7.5 (Sun and H anson, 1975).

B) T h e prim itive liquid composition, unm odified by crystal fractionation or other
processes, was estim ated by back calculation to a Mg-value of 6 8 by the addition of
olivine (Table 9). The result of this calculation shows that a least evolved rock
com position (IP-5) could have been derived by removal of 9% olivine (primitive
liquid = 0.91 least evolved rock + 0.089 Olivine). T he R E E pattern of the primitive
liquid resem bles that of the T-type or P-type M O RB (data from LeRoex et al., 1983;
Sun et al., 1979).
m elting g reater than

In order to generate such parental m agm a with a degree of
2 0

%, the upper m antle source would have to have a chondrite-

norm alized pattern enriched in LR EE.

C) O nce the m antle com position and primitive liquid com position are established,
it may be possible to constrain partial melting models.

The calculated mantle

com position was tested by using partial melting models for their ability to account
for the R E E contents of the prim itive liquid. Figure 23 shows the R E E abundances
of the primitive liquid and 10 to 30% partial melting of calculated mantle
composition. Partial melting calculations were done by the batch melting equation.
In these calculations, m antle compositions were cited from the literature (i.e., in
Figure 23, a)O L:O PX :C PX :G A R = 55:25:15:5, Pankhurst,1977; b)O L:O PX :CPX =

94

Table. 9
Prim itive liquid com position by back calculation for olivine addition.

Oxide (wt.%^

least evolved rock

Prim itive liquid

Olivine

S i0 2
49.58
48.71
40.15
T i0 2
0.99
0.90
0.05
A12 0 3
17.37
15.79
0.00
F eO
9.73
10.11
12.67
M nO
0.16
0.17
0.21
M gO
9.44
12.72
46.56
C aO
9.31
8.50
0.35
N a20
2.64
2.40
0.00
K2.D_______________ 0 J 5 ______________________0 6 8 _________ 0 . 0 0
Prim itive lq. = 0.911 least evolved + 0.89 Olivine

95

Figure 23. C hondrite norm alized R E E abundance patterns as a function of degree
of m elting of the calculated m antle source. R E E content of
prim itive m elt is generated by back calculation from the least
evolved sample by the addition of olivine.

96

Normalized

100

□

Chon.

+
X
<!>

PRIMITIVE MELT
10%
15%
20%
30%

(A) Pankhurst (1977)
1

LaCe

SmEu

Yblu

Chon.

Normalized

100

(B) Shilling (1975)
1

LaCe

SmEu

YbLu

Chon.

Normalized

100

(C) Leeman (1976)
1

LaCe

SmEu

YbLu

97

60:25:15, Shilling, 1975; c) O L:O PX :CPX :PL = 55:20:15:10, Leem an, 1976). The
m elting m odes used in the calculations were cited from experimentally determ ined
values o f previous workers (a)O L:O PX :C PX :G A R = 10:20:40:30, b)O L:O PX :CPX
= 25:20:55, and c)O L:O PX :C PX :PL = 10:20:40:30). The partition coefficients of
olivine, clinopyroxene, orthopj/roxene, and garnet were taken from Frey et al. (1984)
and plagioclase from D rake and Weil (1975).
Based on the R E E concentration, primitive liquids fit well in the range with
20 to 30% partial melting of estim ated m antle m aterial except with respect to Ce.
The highly enriched Ce in the initial m antle composition is probably caused by the
use o f an im proper intercept (close to 0), which likely to be invalid. These melting
ranges are consistent with that of prim ary tholeiitic magma which is generated by

2 0

to 30% partial melting of upper m antle peridotite (Cullers and Graf, 1984).
T he chemical compositions of the studied rock samples were projected into
the pseudo-quaternary system (olivine-clinopyroxene-silica-plagioclase) according to
the m ethod of Elthon (1983). Experim entally determ ined phase boundaries were
taken from Stolper (1980). Figure 24 show that the majority of the studied rock
sam ples are clustered about the olivine + clinopyroxene + plagioclase cotectic at
low pressure. This suggest that most of these samples have been modified by low
pressure fractionation, during which the residual liquid inevitably moved to low
pressure cotectics.

It is apparent from Figure 24 that although the olivine +

orthopyroxene + clinopyroxene cotectic comes close to the cluster of sample
compositions, it does not reach it.
It suggests that the m agm a source for this investigation was generated by 20
to 30% partial melting of a relatively undepleted mantle source and that this magma
differentiated by fractional crystallization of olivine + clinopyroxene + plagioclase
at a relatively shallow depth.

98

The estim ated m antle composition, however, is subject to the errors which
are caused by the following reasons:
1) The differentiation trends of elem ents are scattered due to alteration effects.
These poor correlations can cause im proper intercept values.
2) T he Yb content in the m antle can be vary from
chondrite.

2

to 4 tim es th at of ordinary

Therefore, the absolute R E E concentration in the calculated m antle

could be at m ost

2

tim es g reater than the one presented .

99

Figure 24. Pseudo-liquidus phase diagram s for dikes, H em lock volcanics, and
B adw ater greenstones projected from plagioclase onto the olivinediopside-silica plane and from diopside onto the olivine-plagioclasesilica plane.
Symbols: circle:dikes; cross: H em lock volcanics;
triangle: B adw ater greenstones.

100

Elthon 83
Wt %
1150
-8.16

lO M *

20 kb m w

. lati

OL

PLUG

10 kl

ISkl
1 atm

OL

SI
101

G EOCHEM ICAL INTERPRETATIONS O F TECTONIC SETTING

1. T est of tectonic setting using imm obile elem ent tectonic discrim ination diagrams.

D ifferent types of tectonic models have been proposed for the early
Proterozoic

tectonic

environm ents

of northern

M ichigan

and

northeastern

W isconsin (Cannon, 1973; V an Schmus, 1976; Cambray, 1978; L arue and Sloss,
1980; Larue and Ueng, 1985; Sims and others, 1985). O ne of the m ain objects of
this research is to determ ine the tectonic environm ent of this area by examining the
trace elem ent geochemistry of intrusive and extrusive rocks. It has been recognized
th at volcanic rocks erupted within specific tectonic settings possess distinctive trace
elem ent and, in some cases, m ajor elem ent signatures.
A geochem ical approach toward this goal is com plicated by several factors.
A m ajor problem is interpreting the elem ent abundances in the rock related to
m etam orphism .

T he rock suites under investigation have suffered extensive

m etam orphism from the greenschist to am phibolite facies during the Penokean
Orogeny. A series of well docum ented m ethods utilizing immobile elem ents are
applied with caution in order to estim ate the effects of m obilization (Cann, 1970;
Pearce and Cann, 1971; Floyd and W inchester, 1975; F errara et al., 1976; W ood et
al., 1976; L udden and Thom pson, 1978; M uecke et al., 1979; Pearce and Norry,
1979; Ludden et al., 1982). Pearce and Norry (1979) suggest that the Ti, Zr, Y, and
Nb are not usually transported in aqueous fluids and thus these elem ents are
unaffected by m etam orphism through the greenschist facies (Cann, 1970). M uecke
et al. (1979) show that the R E E as well as Ti, P, Y, Zr, Hf, and Nb are essentially
unaffected by m etam orphism to amphibolite facies.

They concluded that the

elem ents Ti, P, Zr, Hf, Ta, Sc, Nb, Y, and H R E E 's in basalts are resistant to
102

alteration and m etam orphism , while other elem ents such as Sr, Ca, Ba, K, and Na
can be shown to be m obile even during low grade alteration (H um phris and
Thom pson, 1978; G elinas e t al., 1982; L udden e t al., 1982).

These immobile

elem ents are suitable for use in a tectonic discrim ination diagrams.

W hat these

diagram s do not consider is th e tem poral decrease in global heat flow.

This would

have influenced the depth and degree of partial melting of the m antle and the
likelihood of contam ination by sialic crust.

F or above reasons, in the diagrams

which follow, the field boundaries defined by m odern volcanic rocks serve m erely as
a reference fram ework to which the Precam brian data can be com pared.
Several

discrim ination

schemes

utilizing

distinctive

trace

elem ent

distributions in mafic volcanics have been proposed to aid in the reconstruction of
ancient tectonic settings.

T h e application of such schemes to volcanic rocks of

Precam brian age is based on the assum ption that the ancient and m odern chemicaltectonic systematics of m agm a genesis are basically the same.

a'} Ti-Zr: Figure 25 is a plot of Ti vs Z r used by Pharaoh and Pearce (1984). The
purposes of this diagram are

1

) to identify which samples are basic and thus able to

be classified by basalt discrim ination diagrams; and
volcanic arc and a intraplate origin for the rocks.

2

) to distinguish betw een a
This diagram discriminates

betw een basic and evolved lavas because the dom inant crystallizing phases in basic
magm a (i.e., olivine, pyroxene, plagioclase) have an insignificant effect in the T i/Z r
ratio of the melt. However, w hen a Ti bearing phase begins to crystallize and the
melt evolves from basic to acid, the removal of Ti results in a decrease in the T i/Z r
ratio (W atters and Pearce, 1987). In Figure 25, it is apparent that the all rocks fall
in the basic lava side and that the majority of the rocks plot in the within plate basalt
(W PB) field. A C F processes do not significantly alter the tectonic indicators in the
T i-Zr plot (U eng et al., 1988) because Z r concentrations are sim ilar in the crustal

103

Figure 25. Plot o f T i vs. Z r for the dikes, the H em lock volcanics, and the Badw ater
greenstones. M O RB, W ithin-plate, and Arc-volcanic field locations
taken from P haraoh and Pearce (1984).

104

10

i

*

i —1 ■■i

i r1 ■i it

/

/

WPB

e
CL
CL

10

-

105

□ 0

o

Lavas

\

10*

*

l_J«J

10

1000

Log

Zr

ppm

*

D ikes

a

6.W .

□

H em lock

G reenstones
V o lcan ics

m aterial and the m agm atic differentiates of the interm ediate stage, and because the
tendency to lower the Ti concentration of the m agm a by assimilating supracrustal
rock is overshadowed by an enrichm ent trend caused by differentiation.

b l Ti-Zr-Y:

Samples w ere plotted in Ti-Zr-Y (Pearce and Cann, 1973) to

distinguish within plate basalt (W PB), ocean-floor basalt (O FB), low-K tholeiites
(LKT), and calc-alkaline basalt (CAB) (Figure 26). The WPB affinity of the rocks is
a dom inant feature of the plot. However, a fairly large num ber of rocks plot in the
O FB fields. This kind of plot pattern has been interpreted by M orrison (1978) and
H olm (1982) as representative of incipient spreading within continental crust. It
thus appears th at the basaltic rocks plot within and betw een W PB and O FB on this
diagram and suggests th at they have characteristic of continental basalts of
transitional setting; either continental rifting or back arc basin.

cl Z r/Y -Z r: Figure 27 (P earce and Norry, 1979), though not providing a com plete
separation of WPB and M O RB, effectively distinguishes betw een these types and
volcanic arc basalts. The rocks cluster mainly in the WPB field, with a few samples
in the M ORB field.
Based on Figures 25, 26, and 27, most of the rocks from the study area
plotted in either the W PB field or the M O RB field. O f particular interest is that the
less evolved rocks plot in the M O RB field and evolved rocks show a trend into the
WPB field as seen in the Z r/Y vs Z r plot. Although these diagrams do not provide
a separation of norm al M O R B (N-type) and plum e type M O RB (P-type), chemical
compositions of the least evolved samples are similar to that of transitional type
M ORB (T-type). T he Z r/Y vs Z r plot (Figure 27) show two differentiation paths;
one is the Rayleigh crystal fractionation path (CF) and the other is assimilation
fractional crystallization path (A FC). T he latter represents the trend of assimilation

106

Figure 26. Plot of T i-Zr-Y for the dikes, the H em lock volcanics, and the Badwater
greenstones. Locations of basalt fields are taken from Pearce and
C ann (1973). WPB: within plate (intraplate) basalts, LKT: low-K
tholeiitic basalts, OFB: ocean floor basalts, CAB: calc-alkaline
basalts.

107

Ti / 1 0 0
* Dikes
^ B.W. Greenstones
□ Hemlock Volcanics

Figure 27.

Plot of Z r /Y vs. Z r for the dikes, the H em lock volcanics, and the
Badw ater greenstones. Basalt field locations are taken from Pearce
and Norry (1979).
Line A C F m arks the sim ulation of AFC
differentiation p ath with R = 0.4, O L:C PX :PL = 0.05:0.65:0.3,
starting m aterial is IP-5. Line C F m arks the differentiation path of a
crystal fractionation m odel (CPX :PL = 0.65:0.35).

109

UL.

1000

10

Log

Zr

*

D ikes

a

B.W .

□

H em lock

G reen sto n es
V o lcan ics

in supracrustal rocks (Z r/Y

>

10, data from U eng et al., 1988) during

differentiation of magma. Based on Figure 27, the A FC trend shows a good fit to
the data. Thus, these diagram s reinforce and com plim ent previous conclusions that
trace elem ent distributions are related to A FC processes and that the source magma
o f the dikes, the H em lock volcanics, and the Badw ater greenstones are chemically
n ot significantly different from T-type M O RB compositions.

ill

2. Geochem ical patterns of the rock suites
In this section the geochemistry of the basalts from the study area are
com pared with that of basalts from other tectonic settings such as m id-ocean ridges,
intraplate

oceanic

islands,

continental

tholeiites

(CTB),

and

subduction

environments.
M O RB norm alized geochemical patterns (Figure 28 and 29) provide a useful
m eans of com paring basalts based on the analyzed elem ents.

Pearce (1982)

proposed the use of N-M O RB norm alized L IL /H F S elem ent distribution patterns
to com pare basalts. H e used a com prehensive range of elem ents, including Sr, K,
Rb, Ba, Th, Ta, Nb, Ce, P, Z r, Hf, Sm, Ti, Y, and Yb. LIL elem ents (Sr through Ba)
in this list are relatively soluble in aqueous fluids, while the H FS elem ents (Th
through Yb) are relatively immobile during m etam orphism due to low solubility.
Figure 28 illustrates some typical patterns of recent basalts of known tectonic
environm ents normalized to N-type M ORB (N-M ORB data from V iereck et al., in
press).
Intraplate alkali basalts (Kula in Figure 28a) exhibit an enrichm ent of all
elem ents relative to N-type M ORB, sim ilar to the p attern due to either
incom patibilities of the various elem ents in small degree m antle melts or generated
from the enriched m antle source. T he degree of enrichm ent of each elem ent is
related to its incompatibility relative to garnet lherzolite.

Thus the most

incom patible elements, Th, Ba, and Nb, are most enriched whereas Y and Yb
(com patible with garnet) show little change relative to M ORB.
Com pared to N-type M ORB, calc-alkaline volcanic arc basalts (Figure 28b)
are relatively enriched in Sr through Ba. The distinguishing feature of the enriched
elem ents is their low ionic potential (charge/radius) and hence their greater
tendancy to be mobilized by aqueous fluids.

112

For this reason, this enrichm ent

Figure 28.

G eochem ical patterns of basalts from known tectonic environments
norm alized to N-type M O RB (data from V iereck et al., in press).
D ata sources for Figure 25a cited in M arsh (1987), 24b cited in
M arsh (1987) and C hen and Frey (1983), 24c cited in W eaver et al.
(1979), 24d cited in Thom pson (1982), 24e cited in M arsh (1987) and
Peccerillo and Taylor (1976).

113

100

0

K i l a u e a (OIB)
K ula (OAB)

Rock/N-MORB

a

S r K R b B a T h T a N b L a C e P Z r H f S m T i Y Yb

100

„

Rock/N-MORB

<> New B r i t a i n (IAB)
+■ Kastamonu (CAB)

10
S r K R b B a T h T a N b L a C e P Z r H f S m T i Y Yb

100

Rock/N-MORB

+ Bridgem an (BAB)
X P e n g u in I s I n . (BAB)

10
S r K R b B a T h T a N b L a C e P Z r H f S m T i Y Yb

114

100

Rock

/N-MORB

□ BTVP (Skye l a v a )
O BTVP (Mull l a v a )

. 10
S r K R b B a T h T a N b L a C e P Z r H f S m T i Y Yb

100

Rock/N-MORB

* L e s o t h o (CTB)
❖ E te n d e k a (CTB)

10
S r K R b B a T h T a N b L a C e P Z r H f S m T i Y Yb

115

Figure 29. G eochem ical patterns of samples of study area norm alized with respect
to N-type M ORB. Plotted data are listed in A ppendix 2.

116

DIKES/N-MORB

100

10
Sr K flb Ba Th Nb La Ce P Zr Hf Sm Ti

Y Yb

Sr K Rb Ba Th Nb La Ce P Zr Hf Sm Ti

Y Yb

Sr K Rb Ba Th Nb La Ce P Zr Hf Sm T i

Y Yb

HEMLOCK/N-MORB

100

10

BADWATER/N-MORB

100

10

probably results from enrichm ent of a m antle source region by aqueous fluids from
the subduction zone (W eaver et al., 1979; Pearce, 1982).

Figure 28c shows

geochem ical patterns of basalts from Bridgeman and Penguin Islands which are
attributed to recent back-arc extension behind the South Shetland volcanic arc off
the A ntarctic Peninsula. They exhibit 1) an enrichm ent in elem ents of low ionic
potential and in Th, Ce, and P, characteristic of calc-alkaline basalts, and 2) an
enrichm ent in all elem ents from Sr to Ti (except Nb) characteristic of intraplate
tholeiites. T he m ost obvious explanation for these patterns is that the m antle source
regions have suffered at least two episodes of enrichment, one related to and the
oth er unrelated to subduction (Pearce, 1982). The m antle source for these lavas
seems to have undergone enrichm ent in K, Rb, and Ba, possibly resulting from
dewatering of the subduction slab (W eaver et al., 1979).

The lower absolute

abundance of Nb is typical of back-arc basalt from the spreading center (Sanders et
al., 1979). Selected m odern suites of continental tholeiitic basalts (Figure 28d and
28e) erupted in areas of strong lithospheric attenuation also give patterns which
exhibit enrichm ent in the m ost incom patible elem ents and depletion in Nb and P
with respect to their neighboring elements.
It is difficult to chemically distinguish the CTB and OIB with respect to
degree of enrichm ent of overall elements.

Both have enriched LIL and HFS

elem ents, however, they show a distinctive difference in the concentration of Nb.
Histogram s of L a /N b ratio for examples of OIB, CFB, and subduction related
basalts are given in Figure 30. Although this discrim inant alone is insufficient to
determ ine the paleotectonic environment of a single sample, it is adequate to
distinguish betw een CFB, OIB, and IAB. The geochemical patterns of the basaltic
rock groups from the study area (Figure 29 and 30b) have very similar distribution
patterns and resem ble the continental tholeiitic basalts in regard to the degree of
enrichm ent of L IL /H F S elem ents and Nb and P depletion.

118

The interpretation of these data strongly favor a m odel of intrusion into a
crustal environm ent undergoing lithospheric attenuation.
F or all geochemical discriminants used in this chapter including Ti-Zr, Ti-ZrY, and Z r/Y -Z r, all studied samples plot in the both the intraplate basalt and ocean
floor basalt fields.

T he rock samples have higher contents of several mobile

incom patible elem ents such as K, Rb, Ba, and Th than M ORBs while the
abundances of other incom patible elem ents such as Zr, Hf, Ti, and P and
corresponding ratios are within the range of oceanic tholeiites. In the rock samples,
P zO ^ /T iO z = 0.1-0.14; T i/Z r= 101-128; Z r /H f =26.2-32.6; these values are within
the range of M ORB.
Based on the Z r/Y vs 2 r, Ti—
Zr, and TPi—
i^r—
Y plots, less evolved rocks mostly
plotted in the OFB field. T he geochemical differences betw een continental and
oceanic basalts have been discussed for many years. T here are several hypotheses
which have been proposed to explain the geochemical characteristics of continental
tholeiites including the generation of parental m agm a from heterogeneous enriched
upper m antle (Leem an, 1970; Leem an and M anton, 1970; Sheraton and Black,
1981), variable degrees of partial melting (Jam ieson and Clarke, 1970), and crustal
contam ination (Engel et al., 1965; Hedge, 1966; C arter et al., 1978; Norry and
Fitton, 1983; Dupuy and Dostal, 1984). Bryan et al. (1977) have dem onstrated that
many mechanisms invoked for the origin of continental tholeiites such as variable
degrees o f partial melting and high pressure ecologite fractionation can not account
for the observed variations of incompatible elem ents (Dupuy and Dostal, 1984).
Thus, it appears that the geochemical differences between continental
tholeiites and M ORB are due either to crustal contam ination or derivation from a
different m antle source (i.e., continental tholeiites generated from an enriched
heterogeneous subcontinental upper mantle source).

Figure 29 shows that the

patterns of continental tholeiites which have typical crustal features characterized by

119

a depletion of Nb, and P and enrichm ent of K, Rb, Ba, and Th. Also, the studied
rock suites clearly show evidence of crustal contam ination. This type of pattern is
attributed to the assim ilation of the continental crust and is supported by isotopic
d ata (Thirlwall and Jones, 1983). Allegre et al. (1982) have noted the Nd, Sr, and
Pb isotope d ata are consistent with the generation of continental tholeiites and
M ORB from depleted upper m antle sources. F urtherm ore, continental tholeiites
from the northw est D eccan (M ahoney et al., 1982) and N orth A tlantic Tertiary
basalts from Baffin Bay (O'Nions and Clarke, 1972) exhibit a similar chemical
pattern to oceanic tholeiites.
It has been suggested that the continental tholeiites and M O RB are
generated from a depleted upper m antle source, and that the enrichm ent of LIL
elem ents and L R E E in continental tholeiites are due to the contam ination process
while their eruption through varying thickness of continental crust.

However,

although the studied rock suites have chemical characteristics similar to M ORB, it
seems unlikely th at the studied rock suites were generated from the same source as
M O RB in regard to the abundances of the trace and rare earth elem ent as
previously m entioned.

The magm a source for the studied rock suites exhibits a

undepleted L R E E pattern, and the least evolved rocks show a relatively enriched
incom patible elem ent similar to T-type M ORB ((L a/Y b )c = 2.3-3.0; Y /N b = 1.584.0;

Z r/N b = 6.5-12)

which

are

distinctively

different

from

N-M ORB

((L a /Y b )c = 0.3-1.1; Y /N b > 8 ; Z r/N b > 17, data from LeRoex et al., 1983).
Based on the enrichm ent of incom patible and light rare earth elem ent
patterns, it is clear that the m agm a source for the studied rock suites was not a
depleted upper m antle (source for N-M ORB) but a undepleted source similar to
that of T-M ORBs or an enriched reservoir in the old continental lithosphere ('fossil'
lithospheric m antle). It has been suggested that the T-type M ORBs are generated
by the mixing of the depleted upper m antle (source for N-M ORB) and an enriched

120

Figure 30. H istogram of percent of frequency vs. L a/N b . a) H istogram of L a/N b in
island-arc basalts (LAB), continental flood basalts (CFB), and
oceanic island basalts (OIB) (from Thom pson et al., 1985). b)
H istogram of L a /N b for the investigated rock suites.

121

IAB
-EQrEZL-tTrrrri
M
fl>
a
E
<a

CFB

CO

JSL

)
-Q
E
3
0

OIB

Z

2

3

4

La/Nb

(a)
ALL ROCKS

D IKES

<o

0

at

1 2

3

40

4

La/Nb

La/Nb

BADWATER

HEMLOCK

40

at

La/Nb

(b|
122

40

m antle 'plume' (source for P-M ORB). Thus, it is possible to mix two different types
of m agm a within the study area when gradual decom pression during rifting enabled
concurrent melting of upper, m ore depleted m antle, and enriched lower m antle (Ptype source). Thus, a T-type M O R B source could be possible m agm a source for the
studied rock suites, however, the isotopic data for P-type M O RB suggests that the
enrichm ent in incom patible elem ent is a relatively recent event ( less than 300
m.y.b.p.; Sun et al., 1979). F o r example, P-type M ORBs have higher R b /S r ratios
than N-type M ORBs and also higher initial ^ S r / ^ S r ratios (0.7033 versus 0.7026).
If the P-type M O RB source had had such a high R b /S r ratio since the form ation of
earth, then the ^ S r / ^ S r ratio would now be about 0.7066 (Sun et al., 1979). This
indicates that the enrichm ent in R b (or other incom patible elem ents) is a relatively
recent event. Furtherm ore, L R E E depleted samples (generated from a depleted
source) w ere not found am ong the least evolved samples. F or these reasons, the
magm a source for the studied rock suites was different from the present day T-type
M O RB source.

Therefore, the m agma source for the studied rock suites was

probably 'fossil' lithospheric m antle as proposed by Allegre et al. (1982).
According to this m odel of the mantle, there are two layers, a convecting
upper m antle, which is the source for MORBs, and the lower m antle which is source
for OIB and continental alkali basalts.

The lithospheric m antle attached to the

continent is a fossil upper m antle. They proposed a chemically zoned lithosphere
which grew, due to therm al accretion at the expense of the convecting upper mantle,
by continuous addition of new m aterial at the base of the preexisting continental
lithosphere.

This is because the older convecting m antle ( > 1.8 G a) was

undepleted, while the most recently accreted material, which forms the lower part of
the present lithosphere, corresponds to a younger very depleted m antle.

Also,

D uncan (1987) suggested that the subcontinental lithospheric m antle has relatively
enriched L R E E characteristics at ages betw een approximately 1 and 2 Ga.

123

Therefore, based on the trace elem ent patterns and relative abundances, this study
supports previous conclusions th at the studied rocks are a result of a relatively
undepleted p aren t m agm a (sim ilar to present day T-type M O R B ) which was
modified by crustal contam ination.

This shifted the com position to that of

continental tholeiites as th e rocks evolved.

124

3. Tectonic m odel

C haracterization o f past tectonic environm ents is m ore difficult than
characterization of active regimes, and becom es progressively m ore difficult further
back in the past because the geologic record is less com plete.

O ne exciting

possibility for determ ination is th at chemical characteristics of rift-related basaltic
volcanism may help in distinguishing the particular tectonic environm ent in which
the rift form ed. In this study, three possible tectonic m odels were considered; 1)
subduction related plate m argin m odel (V an Schmus, 1976), 2) rifting of passive
continental margin m odel (Cambray, 1978), and 3) foredeep model (Hoffman,
1988).
T he subduction related plate margin model (V an Schmus, 1976), in which
the study area represents a back arc or foreland basin assemblage, seems suitable
model for the area w ithout consideration of the chemical characteristics of the rock
suites. According to his m odel, the m agm a which supplied the dikes and the flows
should be related arc volcanism, however, the geochemical characteristics of the
rock suites (Figure 29) are not associated with arc volcanism (Figure 28 b and c) and
show a lack of chemical characteristics of back-arc magm atism but are com parable
to rift zone tholeiitic basalts which was not related to subduction activity (Figure 28
d and e).

Thus, this m odel can not be supported based on the chemical

characteristics of the rock suites.
An alternative tectonic model, the foredeep model, was proposed by
Hoffm an (1988) which interpreted the early Proterozoic volcanism in the southern
Lake Superior region as a product of foredeep magmatism similar to the Taiwan
Strait, the Persian-A rabian Gulf, and the Ganges River basin. H e suggested that
flexural response of continental lithosphere due to loading of thrust sheet during

125

arc-continent collision induced m agm a generation in the foredeep. According to his
m odel, the pre-foredeep deposits are the Chocolay G roup, outer-ram p sedim ents
are represented by the M enom inee G roup, and the axial deposits by the Baraga
G roup. F oredeep m agm atism is a possible model to explain the evolution of the
B araga G roup volcanism based on geochemical considerations, because the magma
generated in this m odel will essentially be crust-contam inated M ORBs similar to
the studied rocks in this investigation.

However, a m echanism initiating partial

melting of subcontinental m antle in a foredeep model is still in doubt because the
m elting is dom inated by adiabatic decom pression (Allegre et al., 1982).
Cambray's (1978) m odel is that the Chocolay G roup strata were deposited in
a cratonic setting and that the strata of the M enom inee G roup show features which
are inferred to indicate initiation of rifting which generated the basaltic volcanism.
Based on the com parison of geochemical patterns of these suites to the known
tectonic environments, these suites point to a tectonic setting in which tholeiitic
m agm a was em placed producing the dikes and flows, during rifting is suggested.
T he geochem ical patterns of the studied rock suites are analogous to the that of the
lavas from the British Tertiary Volcanic Province (BTVP; Skye and Mull lavas)
which w ere generated during the opening of the N orth A tlantic O cean (Brooks and
Nielsen, 1982; Thom pson, 1982) and to continental tholeiites from E dendeka in
w estern Africa which erupted in a rift environm ent related to the separation of
southern Africa from South A m erica (Duncan, 1987).

T here are obvious

sim ilarities in geochemical patterns between rocks of the study area and those of the
BTVP and Edendeka, both of which appear to represent rifted continental margin
environments.

Therefore, Cambray's (1978) m odel seems the most favorable to

explain the tectonic evolution of the study area. These similarities also imply that
processes of Proterozoic crustal evolution are similar to these m odern analogs. The

126

result of this work seem, therefore, to indicate that a plate tectonic system probably
operated in the Early Proterozoic.
Based on all the geochemical argum ents presented for a source with M ORB
and CTB affinities, and com parison of the chemical sim ilarities to the m odern
tectonic settings, a speculative tectonom agm atic m odel can be form ulated.

T he

model which best explains these relationships is best suited to the adoption of the
m odel of Cam bray (1978).

A rchean dikes related to mafic intrusive activity

occurred in a span of time bracketed by late A rchean deform ational events and the
deposition of the early Proterozoic sedim ents (Baxter and Bornhorst, 1988). The
m agm a source of these dikes was probably from enriched A rchean m antle (Figure
31a). Over time, a decline in h eat flow and would have allowed lithospheric density
to increase to a point where subduction could occur and plate tectonic process
initiated.
D eposition of Chocolay G roup sedim ents on the passive rifted continental
m argin (Figure 31b).

The sedim ents consisted of conglom erates and lam inated

m udstones and seems to represent the infilling of an uneven topography (Cambray,
1984) such as pre-existing linear topography based on unim odal direction of
paleocurrents (Larue and Sloss, 1980). T he depositional environm ent was a shallow
epicontinental sea as suggested by Cam bray

(1978).

This

shelf sea or

miogeosynclinenal pattern was intrupted by doming and rifting giving rise to a series
of fault bounded throughs in which turbidites, and later banded iron formations
accumulated.
Comparisons of total strength indicate that continental lithosphere is weaker
than oceanic lithosphere by about a factor of 3 (Vink et al., 1984). Assuming rifting
occures in the weakest area, differences in total strength results in the preferential
rifting of continental lithosphere.

Thus rifting, if close to an ocean-continent

boundary, was m ore likely to occure within the continent than within the ocean

127

basin or at boundary. A com plicated convection p attern in the m antle is probably
responsible for doming and cracking the crust thereby giving rise to extentional
fractures and eventually to rifts (Figure 31c).

D uring this lithosphere thinning

event, the cracking upsets the tem perature/pressure balance of the underlying
zoned lithosphere due to adiabetic decom pression which resulted in its partial
melting. Also, the continental lithosphere, which in its u pper p art was rich in U, Th,
and K, can provide the heat necessary for such melting. T he m agm a source for
these intrusive and extrusive rocks was the relatively undepleted lithospheric upper
m antle. T he m elting of the magm a source probably took place at shallow depth due
to the high geotherm al gradient and decom pression during rifting.
Thick gravity flows accom panied by regional subsidence and deposition of
the late B araga G roup rocks, is similar to the pattern which accom panies growth of
m ore recent of ocean basin (Figure 3 Id). Sediments thicken to the south, suggesting
the form ation of a sedim entary wedge on the margin of a developing rifted
continental

margin.

Finally,

plate

collision

occurred

with

accompanying

deform ation and m etam orphism of the sedim ents and basem ent rocks (Figure 3 Id).

128

Figure 31.

R econstruction showing tectonic evolution in the southern Lake
Superior region (modified after Larue, 1983). a) A rchean dike
intrusion related to rifting. b)Chocolay G roup depositions on the
passive rifted margin,
c) M enom inee G roup deposition and
initiation o f rifting accom panied by extensive volcanism of early
B araga G roup rocks, d) D eposition of late B araga G roup rocks
during rapid subsidence of basin.
e) P late collision with
accompanying deform ation of continental margin.

129

N

"

‘"IBJ

A rchean dikes intrusion

Chocolay G roup sedim entation
on the passive rifted (?) margin

M enominee G roup sedimentation
and extensive volcanism of early
B araga G roup rocks
‘Ste-.s

•/:'

-s

late Baraga G roup rocks
sedim entation during subsidence
and drifting stage

plates collision

130

CONCLUSIONS

D espite the age and m etam orphism of the studied rock suites, geochemical
analysis, especially for im m obile elem ents, has provided useful inform ation to
constrain the petrogenetic relationship betw een dike swarms and volcanic piles
(H em lock volcanics and Badw ater greenstones), and the paleotectonic environm ent
of the

studied

area.

G eochem ical

analyses,

tectonic

comparisons

using

diagram m atic methods, and lim ited chemical modelling of rocks from the dike
swarms and the volcanic piles allow the following conclusions:
1. G eochem ical data indicate that the dike swarms, the Hem lock volcanics, and the
Badw ater greenstones are tholeiitic; no alkalic basalts were found. The absence
of the alkaline basalts within the region m eans that early Proterozoic magmas
w ere generated at relatively shallow depths, under the influence of a high
geotherm al gradient.
2. Similar chemical trends within the dike swarms and volcanic rocks indicate that
these suites were generated from the same source. The conserved elem ent ratio
plots support this hypotheses. It appears that the dikes, the Hem lock volcanics,
and the Badw ater greenstones are comagmatic and that the dikes served as
feeders to the volcanic piles.
3. If the dikes, the Hem lock volcanics, and the Badwater greenstones are
comagmatic, then the stratigraphic position of the Badwater greenstone with
respect to the M ichigamme Slate needs to be revised as proposed by Ueng et al.
(1988). However, the Badw ater greenstones overlies the Michigamme Slate in
the northern portion of Crystal Falls area (Jam es et al., 1968).

Also, the

Badw ater greenstones exhibit less contam inated characteristics (less Nb

131

depletion, less Rb, Ba, Th, and K contents) as com pared to the dikes and the
H em lock volcanics. It is possible th at the Badw ater greenstones were erupted
at a later stage than the dikes and Hem lock volcanics.

Therefore, if the

m agm atic activity lasted a long tim e span, the present stratigraphic relationship
betw een M ichigamme Slate and Badw ater greenstones could be correct. For
these reasons, m ore careful consideration of field relationship betw een the
B adw ater greenstone and M ichigamme Slate is needed before changing the
stratigraphic positions.
4. G eochem ical characteristics of the intrusive and extrusive rocks show evidence of
crustal contam ination, which occurred during the em placem ent, at depth where
tem perature

differences

betw een

m agm a

and

country

rocks

are

less.

Assimilation of crustal rocks have greatly affected the R E E pattern and
elem ental abundances, especially in Nb and incom patible elem ents, which are
enriched in crustal rocks.
M ost o f the least evolved rock samples plot in the M ORB field in
tectonic discrim ination diagrams, and these rocks are chemically similar to
present day T-type M O RB compositions. Also, the estim ated magm a source
shows a relatively undepleted L R E E /H R E E pattern. Thus, with consideration
of assim ilation effects, it is suggested that the rocks of the study area were
derived from a chemically M ORB-like, relatively undepleted, lithospheric upper
m antle source. The relatively undepleted parent modified by A FC process for
the studied rock suites and these processes shifted the rock composition to that
of continental tholeiites as the rock evolved.
5. Based on all the geochemical characteristics and tectonic discrimination
diagrams, the studied rock suites em placed during rifting.

The geochemical

patterns of these rocks are similar to those of British Tertiary Volcanic Province
and continental tholeiitic basalts from Edendeka, which erupted in m ore recent

132

rift environments. T hese similarities also imply that processes of Proterozoic
crustal evolution are sim ilar to these m odern analogs.

Therefore, the

Cambray's (1978) tectonic model seem s the most favourable to explain the
tectonic evolution o f the studied area.

133

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144

A PPEN D IX 1: CIPW norm and M ajor elem ents compositions.
(* represents A rchean (?) dikes)

Dikes

S102
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti02
P205
MnO
LOI
TOTAL

MR-2
MR-1
FO- 1
4 8 . 36 " 5 1 7 5 5 " 4 6 . 5 3
13.74
12.51
12.89
13.05
14.81
14.38
8.02
4 . 54
6.25
7.98
9.64
4.65
1.63
2.59
2.39
.77
1.07
1.39
1 . 75
2.26
2.41
.27
.16
.22
. 19
.22
.23
97.22
94.41
97.76

GR- 1
T5";ST“
14.30
12.97
10.56
7.03
1.77
1.53
1. 9 2
.13
.23
-

96.25

GR- 2 *
4 8 . 53
17.33
11.08
4.61
8.09
3.81
1.10
2 . 74
.50
. 19
9 7 . 98

GR- 3A
50.17
13.19
10.97
9. 73
8.40
2.36
.31
. 78
.06
. 18
96.15

GR- 3B
56.35
14.64
-

10.63
8. 95
9.91
1.97
. 79
. 63
.05
. 17
98.09

GR- 4
49.11
13.63
11.98
3.81
7.06
3.87
1.45
2.45
.57
. 18
94.11

MG-1*
48.28
14.52
16.98
3.73
3.52
.37
4.90
3.53
.56
.27
9 6 . 66

NR P - 2 :
53.27
12.56
15.76
2. 46
4.18
3.11
2.26
2. 5 2
1.16
.24
97. 52

10. . 0 2
. 18
13. . 8 7
27. . 33
13. . 6 6

-

NORMS
<r

2.. 0 7

6. . 2 7

. "'5..65

C
Or
Ab
An
Ne

.53
8!. 7 9
21., 65
22..81

6. , 54
22. , 6 8
20 . . 0 3

4. . 7 3
14. 35
26..62

9. . 4 9
15. 72
27.. 88

6. . 6 9
3 3 . 19
27.. 73

1 .. 9 2
20. . 9 5
25 . 6 9

4. . 8 0
17. . 14
29 . 58

9. . 19
3 5. . 14
16. . 6 7

8, . 7 5
3 .72
30. . 3 7
3. . 28
14. . 4 8

21. . 38
14. , 0 7
3 . 12

8.. 13
11. . 7 0
16. , 2 6
3., 4 2

9. . 2 1
16 . , 19
16..67
3. . 3 4

3. . 2 8
13., 84
7. 3 3
3., 0 4

4. . 2 7
5. . 4 7
4. . 8 0
2. . 54

7. . 3 6
25.. 43
13.. 79
2.. 5 7

8. . 6 1
22. , 62
1 3. . 13
2. . 4 4

7. . 0 6
10. . 0 6
1 2. . 3 9
2. . 8 7

9, . 74
17. . 30
3.. 97

6. 3 6
17 . . 17
3. , 6 5

4. , 9 0
.69

4. . 4 4
.54

3. , 4 6
.39

1 . 23

.15

4. 9 9
1. . 4 5
09
. 12
7. 0 6
3. . 15
3. 8 8
6. . 91
8. 51
3 2 . 18
42. 43
5. 0 0

4. 9 7
2. . 8 5

21. , 38
14. , 0 7
51. , 30
58. . 7 5
5. . 0 0

. 12
.21
. 13
8. 61
5. . 16
3. 0 0
1 7 . 45
10. 13
6 3 . 31
6 6 . 11
5. , 0 0

7. . 0 3
1 .. 3 9

9. 21
4. . 4 6
4. 59
1 1 . 73
1 2 . 07
64..97
5 0 . 18
5. . 00

5. 3 6
1 .. 2 2
4. 4 5
4. 30
4. 2 7
2. , 21
1 . 94
3. 2 6
2. 8 6
45..52
49. 09
5. 0 0

1 .. 5 5

8. 13
3.. 41
4. 74
8. 29
11. . 52
4 6 . , 89
4 1. . 5 3
5. . 00

3.. 8 3
32
9 . 65
5. 6 3
3. 2 8
2. . 0 2
1 . 07
1 1 . 82
6. 2 6
63. 94
6 5. 36
5. 00

.59

AC

Ns
Wo
En
Fs
Mt
13Mt
rim
n
Ap

Fo
Fa
Di:=Wo
=En
=Fs
Hy- =En
=Fs
Pl ag
MgVAL
FeRAT

145

7. 3 6
4. . 5 0
2. 44
20..92
11. 35
55..08
67.,27
5. , 0 0

74
30
51
73
5. 0 0

9.
17.
81.
33.

6. 3 6
17. 17
3 3. 3 3
2 6. 56
5. 0 0

Dikes

Si 0 2
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti 02
P205
MnO
LOI
TOTAL

NRP-3
47. 31
14. 77
11. 94
8.69
6.45
. 42
4.41
2.47
. 32
. 17

NRP-5
49:'T6

15. 23
-

11. 93
6.56
10. 38
2. 00
1. 06
1. 42
. 15
.20

IP-1

IP- 2

I P- 3

"35 :'7S ' 5TT58- '"45':T8

IP- 4

I P- 5

46.42

47. 38

16 . 6 0

15 . 5 2

15.27

15 . 1 6

15.62

-

-

-

-

11. 02
7. 8 2
10 . 1 6
1. 7 6
.46
1. 20
. 12
.21.

10. 71
6.62
11 . 2 7
2.28
. 44
1.12
. 11
. 22

10. 93
6.78
7.55
1. 46
2.10
1.28
. 12
. 13

10. 64
8.79
7.73
3. 21
. 85
1. 11
.05
. 15

-

9. 30
9.02
8. 90
2. 52
. 72
. 95
. 04
. 15

..

IP- 6*g - WL-1
WL-2
“ ST-TT "5'4T $
1 3 . 8 9 16 . 0 3 15. 98
16 . 6 7 10. 33 11. 53
3.97
5. 7 5
7.95
2. 77
3.39
6. 35
1.57
3.14
4. 48
3. 77
1. 23
. 39
2. 54
. 72
. 76
. 89
.07
. 06
. 19
.21
. 16

-

-

-

-

-

-

-

-

-

-

96.95

98 . 0 9

95.05

98. 62

91.29

94 . 5 7

95.58

95.06

97.89

97 . 0 9

2..37
39 .04
23 . 15

10 .97
4 .62
23 . 16
13 . 81
13..81

3..71
8..09
5.. 10
2.. 37

14..89
14..41
2., 67

NORMS
Q
C
Or
Ab
An
Ne

.35

1..77

27 . 14
3..70
26..44

6..45
17..42
30..31

2 .89
15.. 81
35 .13

2..66
19,. 73
30..81

13..72
13..66
31 .63

5 .36
28 .97
27..42

4.. 49
22 .48
33..58

8..00
3..58
7..75
28..33
11..73

1..96
17,. 15
9..18
2 .77

9..05
16..81
13..75
2..74

7. 33
19..58
12..64
2.. 61

10..70
16.. 86
12..60
2., 44

3..72
17.. 48
12..60
2..69

5..49
3 .57
1..98
2..53

5.. 30
11..53
5., 47
2., 19

10.. 54
18..75
3. 96

4.,89
.79
3..78
2..23
1..96
1..21
, 64
15!, 94
8.. 53
87.,72
62. 78
5. 00

2. 78
, 37

2. 42
.30
,77
.55
7.,33
4.,25
2. 74
15..33
9. 90
68..96
62. 18
5..00

2.. 17
.27

2. 69
.31
83
.66
3. 72
2..08
1. 50
15. 40
11. 11
69. 84
58. 97
5. 00

2.,25
. 13
13..86
8..46
5. 49
3. 34
1. 85
23
13
48! 62
65. 69
5. 00

1. 90
. 10
8! 51
4 . 45
5. 30
3 36
1 . 60
8. 17
3. 88
59. 90
69. 21
5. 00

AC

Ns
Wo
En
Fs
Mt
Pm
nra
i i

Ap
Fo
Fa
Di =:Wo
En
:Fs
Hy=En
:Fs
Pl a g
MgVAL
FeRAT

9.
4.
3.
11.
9.
63.
56.
5.

05
82
94
99
81
51
03
00

10.
5.
4.
10.
8.
60.
58.
5.

70
89
41
97
20
97
89
00

146

5. 14
2. 25

10.
18.
29.
35.
5.

54
75
28
56
00

1,. 41
. 15
8! 62
5..99
3. 71
2. 17
1. 37
5. 93
3. 73
37. 22
64. 07
5. 00

1 .. 50
17

14.
14.
50.
53.
5.

89
41
00
61
00

Dikes

Si 02
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti02
P205
MnO
LOI
TOTAL

WL-4
S i . 22
12. 67
-

MQ-1A
48. S3
12. 93
-

MQ-1B
48.72
13. 19
-

MQ-1C
48.§4
13.38
-

MQ-4
52 . 4 9
15 . 2 6

RQ-1
48 . 2 6
14 . 4 5
-

-

RQ-2*
50.89
1 2 . 48
-

SQ-1A
48.68
14.06

SQ-1B
49.11
13. 54

-

SQ-1C
49. 67
13 . 9 4
-

-

15 . 5 9
5.54
6.22
1.88
1. 03
1.96
. 22
. 19
96.52

15. 07
6. 01
6. 11
2. 52
1. 19
2. 41
. 19
. 19
95. 45

-

-

-

-

-

-

-

-

96 . 9 7

95.79

9 6 . 88

98 . 2 2

98.68

97.45

97.20

97.49

Q

9..37

2 .96

.25

5 .84

2 . 38

2 . 28

1 .57

Or
Ab
An
Ne

6..39
16,.69
24,.22

7,.46
22 . 61
21..69

9..25
22..25
21.. 13

8.. 74
36,.75
14..71

3 .93
27,.61
26 .66

10 .99
18..61
25 . 15

10 . 13
26 .66
15 .74

6 . 38
17 . 03
27 . 58

5 .41
15 .94
27 . 28

4 .41
19 . 13
27 . 09

2..77
14..48
18..00
3..65

3..82
15..88
16..70
3.. 57

6..41
15..73
16..36
3.. 49

2..33
8.. 41
8..51
3.. 53

6..85
19..49
10..69
2.,00

12..89
9.. 81
8..06
2..72

4..92
7.. 46
16..89
3.. 68

7 .49
16.. 49
16..84
3..20

9..15
16.. 69
17..25
3,. 29

8 .27
17.. 48
16..43
3,. 12

3..90
55

4..85
.48

4..72
42

1 . 28

2.. 35
.27

2,.43
. 30

2.. 24
. 27

3..82
1 ..83
1 . 93
14. 04
14. 77
48. 96
48. 03
5. 00

6. 41
3..09
3. 22
12. 63
13. 15
48. 71
48. 34
5. 00

4..08
.54
3'. 76
3..40
12. 89
6..86
5. 63
2. 95
2. 43
57. 48
53. 70
5. 00

5. 52
3..23

2., 77
1 . 23
1 . 53
13. 24
16. 47
59. 21
45. 16
5. 00

4..45
.48
5. 72
6..38
2. 33
1 ..14
1 . 15
7. 27
7. 36
28. 59
49. 36
5. 00

4. 92
1 . 56
3. 54
5. 90
13. 35
37. 13
29. 62
5. 00

7. 49
3.. 64
3. 72
12. 84
13. 12
61. 82
51. 65
5. 00

14. 98
6.05
7. 27
2.52
1 . 50
2.38
. 17
. 19

14.98
6.30
4.12
4. 11
1. 40
2.22
. 19
. 15

8.61
7.53
8.43
3.14
. 64
. 65
. 06
. 16

11 . 8 5
5.93
11. 28
2 . 14
1. 81
2.09
.22
.19

16 . 0 8
2.92
7.16
3.07
1.67
2.83
1.33
. 25

13.84
6. 38
8.99
1.94
1.04
1.19
. 11
. 22

14. 16
6.44
9.69
1.81
. 88
1.23
. 12
. 22

13 . 4 9
6.77
9.26
2.18
. 72
1. 14
. 11
. 21

NORMS
n

1 .34

nC

Ns
Wo
En
Fs
Mt
Hm
11
Ap
Fo
Fa
Di-:Wo
:En
:Fs
Hy=En
:Fs
Pl ag
MgVAL
FeRAT

. 15
6.
4.
2.
15.
8.
49.
66.
5.

85
17
29
32
40
12
96
00

147

9.
4.
4.
12.
12.
63.
51.
5.

15
43
58
26
67
13
31
00

8.
4.
3.
13.
12.
58.
53.
5.

27
16
91
32
51
61
77
00

Dikes
SQ-2A SQ-2B SQ-3A SQ-3B NSW-1
“4 S T 2 " 48. 49 ..4'8. 3'2"TT3TF5” ' l O f f '
A1203 13. 68 12. 87 13. 86 1 4 . 25 15 . 5 0
Fe203
1 7 . 6 3 16. 79 14. 38 1 3 . 3 9 10. 61
FeO
4.22
6.89
MgO
5. 31
7.21
8.10
CaO
1. 28
6.89
4.55
7. 92
4. 13
2.29
3.32
Na20
. 75
3. 91
3.04
K20
1. 18
1. 01
5 . 44
. 89
1.20
3. 36
Ti 02
3.49
1.49
1. 58
1.30
.40
P205
.41
. 15
. 12
. 12
MnO
. 29
. 18
. 18
.21
. 18
LOI
TOTAL 9 4 . 70 96. 67 9 4 . 1 5 9 5 . 2 7 9 7 . 0 6

£j! 0

2

-

-

-

-

NS-1
RP-1
RP-2B
48. 38 ' 557113“ 31 . 4 0
1 3 . 3 9 15. 33 13. 67

-

-

-

15 . 0 2
7.63
6.05
3.19
. 92
1.07
. 08
. 17

-

-

-

12.86
2.57
4.53
3.66
1.70
2.37
. 47
. 23

RP-2A
52.75
13. 20
-

12. 93
6. 31
10. 15
2.22
. 67
. 82
. 09
.21
-

9.43
8.99
9.87
2. 36
. 93
. 69
. 06
. 16

RP-3
51. 6fe
13. 70
12. 53
7. 0 4
9.72
1. 66
. 60
1. 16
. 13
. 23

-

-

-

-

96 . 9 0

98.75

98. 47

98.44

98. 42

3 .25

1 . 58

6 . . 40

4 .06
19..27
26 .01

5 . 62
20 .44
23..21

3..64
14.. 41
28.. 89

NORMS
Q
C
Or
Ab
An
Ne

4..07
5..58
34..44
6. 80
3. 93

7..31
20..32
22..39

6..41
30.. 19
21..42

5..58
35.. 11
19..85

7 .37
26..73
26..08

5 .68
28 . 19
20 .37

9,. 29
.37
10 .28
31..68
19,.85

14. 17
18..68
4.,21

4..47
11..02
17.. 16
3.. 93

.75
15!.23
14..52
3..45

.44
13.. 77
11..49
3.. 17

5..82
10.. 44
6..12
2..46

4..36
14.. 19
13..33
3..50

6..55
13.. 34
2..93

10.. 46
16.. 12
16..06
2., 96

11 .07
22..91
11..54
2.. 15

8 . . 23
17. 99
15..00
2. 87

7. 10
1. 04

6., 69
.99

2., 57
.29
7. 37
4.,76
5. 82
3.. 48
2.,04
6.,97
4. 08
49. 39
63. 89
5. 00

2.. 12
.20
3. ,96
4.. 11
4. 36
2. 20
2. 06
11. .99
11. 27
41. 94
54. 07
5. 00

1. 60
22

1..34
.14

2. 26
32

14.. 17
18. 68
36. 65
41. 11
5. 00

3.. 18
.30
3. 70
3.,41
44
.23
20
13.. 53
11. 30
36.. 11
55. 51
5. 00

4..60
1.. 14

4. 47
1., 77
2., 76
9..25
14..40
52. 42
36..81
5. 00

3..04
.38
2. 25
2..37
75
.37
.36
14..86
14.. 16
41..50
52. 61
5..00

11. 07
6.,91
3. 48
16. 00
8. 06
53. 17
6 8 . 84
5. 00

23
35
63
64
37
6 6 . 72
56. 56
5. 00

5..75

AC

Ns
Wo
En
Fs
Mt
Um
nm
i i

Ap
Fo
Fa
Di =Wo
En
:FS

Hy=En
Fs
Plag
MgVAL
FeRAT

148

6.
13.
38.
31.
5.

55
34
52
65
00

10.
5.
5.
10.
10.
57.
53.
5.

46
14
12
98
94
44
07
00

8.

4.
3.
13.
11.

Dikes

Si 02
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti02
P205
MnO
LOI
TOTAL

RP-4
S o . 46
13. 47
-

NG-2
48. 53
14. 25
-

RP-5
52.14
13. 97

NS-3
44.98
15.68

WF-1
50.79
1 2 . 44
-

WF-2
51 . 2 4
13. 49

WF-3
S4. 46
12. 36

-

-

-

13.15
5.48
6.67
3.16
2. 21
1.60
. 19
.21
97.40

13. 92
3.52
4. 31
2.18
3. 36
2.00
. 37
.21
96.69

21.36
6.14
. 67
5. 35
3.33
. 43
. 09
95. 71

10,. 18

3 .66
9.. 56
33 .61

-

-

12. 23
5.79
9.56
2.42
1. 60
2.53
. 26
. 19
98 . 4 5

11. 82
7.82
9. 6 2
2.22
. 53
1. 83
.21
. 17
97. 00

12 . 0 6
5. 2 4
7.68
2.47
1. 85
2.12
. 25
. 17
97.95

12.69
11.64
6.47
2.35
.46
. 83
. 06
. 20
95.36

1..75

. 34

4..89

9..70
21,.00
21 .71

3..26
19,. 55
28..47

11..27
21.. 54
22..23

2 .88
21,.07
32 .72

8.. 14
15..09
23..33

13 .55
27 . 74
16..70

20,.76
19.. 29
14..66

10..52
14..79
1 2 . .20
2..80

8 . .26
20..27
12..99
2.. 74

6.. 41
13..45
12..69
2.. 77

.37
9,. 78
5.. 17
3.. 00

7..76
12.. 57
16..06
3., 39

6,.82
12..65
13..57
3..04

4..93
.63

3..62
,52

4.. 15
.61

4. 52
.77

10. 52
5. 59
4..61
9..20
7..59
50..83
52..31
5..00

8. 26
4. 80
3. 08
15. 47
9. 92
59. 28
60. 52
5..00

6. 41
3.,23
3. 04
10. 23
9. 65
50. 78
50. 17
5..00

1..67
. 15
14!.67
8..54
. 37
23
. 12
9.. 56
5..05
60., 83
68. 01
5..00

3.. 15
. 47
1 ..06
1 ..25
6..82
3..25
3. 48
9..40
10. 09
37..58
49. 13
5. 00

14. 59
4.84
8. 51
1. 71
1. 32
2.28
. 31
. 22
-

97 . 0 1

WF-4
43.37
14. 97

WF-5
51.22
13. 06
-

WF-6A
49. 47
12. 52
-

13. 56
5. 82
8. 6 2
2.65
1. 1 9
1. 57
. 14
.22

15. 52
5.15
9.62
1. 75
1. 07
1. 96
. 19
.26

-

-

98.05

97. 51

2 .30

4 .83

. 55

7 .25
23 . 12
20.. 85

6 .57
15 . 38
24..03

2.. 16
9.. 17
15.. 66
3.. 25

16..26
23..52
5..07

9.. 31
14.. 94
15..72
3., 12

10.. 12
13.. 32
17..85
3. 59

3., 97
92

6..72
1 ..08

3..07
, 34

3.. 87
.47

NORMS
Q
C
Or
Ab
An
Ne

8.. 40

A

ilC

Ns
Wo
En
Fs
Mt
U
m
nit]
ii
Ap
Fo
Fa
Di =Wo
En
•Fs
Hy=En
■Fs
Pl ag
MgVAL
FeRAT

7. 76
3.,40
4. 34
9. 17
11. 71
60. 72
43. 46
5. 00

149

2. 16
81
1 . 39
8. 36 16..26
14. 28 23. 52
43. 18 100. 00
36. 95 39. 98
5. 00
5. 00

9.
4.
4.
10.
11.
47.
49.
5.

31
47
70
47
02
42
87
00

10. 12
4. 33
5. 80
8 . 99
12. 05
60. 99
43. 47
5. 00

Badwater Greenstones

Di kes

SiO^
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti 02
P205
MnO
LOI
TOTAL

WF-6B
49.39
12 . 5 2
-

15 . 0 8
5.54
9.63
2.08
.64
1.96
. 17
. 25

WF-7A
48 . 1 0
11. 50
1 2 . 72
7.64
9.92
2.88
. 64
3.15
.30
. 18

WF-7B
*738
14. 61
13. 38
6.82
8.98
2. 9 1
1.12
1.74
. 17
. 22

-

-

-

97.26

97.03

97.33

CF-1
CF-2
473"fT s z . z r
16. 85 13. 62
-

11 . 1 1
8.13
8.24
2.92
.34
1.36
. 12
. 16
-

96. 59

CF-4
5 0 . 88
13. 24

9 5 . 78

CF-3
50.30
13.90
13.42
5.45
9.55
2.11
. 07
1. 31
. 12
. 20
96.43

12..06

-

12. 47
3.62
8. 9 2
1. 94
. 82
1. 76
. 23
.17
-

CF-6
51.29
14 . 5 2

12. 53
5.07
10. 57
1.92
. 09
1. 2 5
. 12
. 19
95.86

CF-5
50.00
14. 51
11 . 7 0
5.43
10. 68
2.64
. 04
1.23
. 11
. 18
96.52

96. 47

FLE-2
47. 48
15. 88
10. 60
4. 7 6
16. 95
.29
.08
1. 40
. 13
. 16
97 . 7 3

6.. 74

8.. 66

3., 21

6..99

6.. 30

-

-

12. 85
5. 91
7.16
2.10
.92
1. 40
. 12
. 20
-

NORMS
Q
n

Or
Ab
An
Ne
AC
Ns
Wo
En
Fs
Mt
Urn
nm
11
Ap
Fo
Fa
Di:=Wo
=En
=Fs
By- =En
=Fs
Plag
MgVAL
FeRAT

4..15
3..93
18. 32
23..87

3..94
25.,37
17..24

6..87
25.,57
24..40

2.. 10
25. 81
33..28

5..11
17..31
27..46

.43
18.. 72
29..61

.56
17!, 12
28..71

.25
23!. 36
28..89

5..69
18.. 61
28 .78

. 49
2', 53
43..12

10. 31
14..36
17. 28
3. 50

13..34
16..23
9. 80
2..95

8..65
6.. 84
5..94
3.. 10

3.. 59
11. 13
6..78
2., 59

7..36
9..51
14.. 17
2.,93

8..03
14..23
16..20
3.. 14

10..74
13., 31
15.. 17
2..94

10..76
14., 14
13..95
2., 73

3..17
15.,42
15..27
3..00

17..86
12. 23
11..98
2. 44

3.. 87
42

6..23
,74
2. .51
1..67
13.. 34
7..90
4.. 77
8.,33
5.,03
40.. 46
58., 19
5. 00

3. 43
.42
7.,56
7..23
8. 65
4..50
3. 90
2., 34
2. 03
48.. 83
54.. 15
5..00

2. 70
30
1. .02
4., 71
3. 59
2. 12
1 . 29
9. 01
5. 49
56., 33
62. 90
5. 00

3. 53
.57

2..61
30

2. 50
,30

2. 44
.27

2.. 79
.30

2. 74
32

7. 36
2..98
4. 44
6..53
9. 73
61..33
40. 22
5. 00

8. 03
3..72
4.,23
10..51
11.. 97
61. 27
48. 48
5. 00

10. 74
4..97
5. 67
8. 34
9..50
62. 64
48. 39
5. 00

10. 76
5., 31
5. 24
8. 83
8. 71
55. 29
51. 82
5. 00

3. 17
1 ..57
1 . 55
13. 85
13..72
60..73
51. 59
5. 00

10. 31
4..65
5., 60
9.,71
11. 69
56..58
45. 98
5.,00

150

17.
8.
8.
3.
3.
94.
50.
5.

86
84
66
39
32
45
99
00

Badwater Greenstones

Si 0 2
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti 02
P205
MnO
LOI
TOTAL

FLE-3
45.98
15 . 0 5
12 . 6 9
7.86
11 . 2 9
1. 7 8
. 26
1. 6 6
. 16
. 20
96.93

FLE-4
51 . 2 9
14. 18
12. 21
6. 81
7.03
3.38
.54
1.36
. 18
. 18
97.16

FLE-8
50.95
14 . 8 5
8.89
7.37
10. 98
2. 47
. 42
.97
. 10
. 15
97.15

FLE-9
4 9 . 47
14. 52
10. 13
7.74
12 . 7 6
1. 3 2
. 48
1. 0 7
. 10
. 17
97.76

FLW-1
47.14
15.59
12 . 4 0
6.10
12. 12
1.08
. 34
1.56
. 14
. 18
96.65

FLW-2
4 8 . 14r
15. 64
11. 83
6. 41
11. 08
1. 7 7
. 37
1. 54
. 15
.17
97. 10

1 .74

2..73

3..67

2.. 12

2..51
33..07
21..71

2..57
21..67
29..23

2..92
11.. 52
33..28

2 . 10
9,. 55
38..34

2..27
15.. 57
34 .97

12.. 14
19..58
11..56
2..28

12.,49
15.. 74
6..78
1 , 72

11..09
19..03
10.. 47
2..06

13..08
19., 88
11..93
2. 33

9.. 83
15,. 88
14.. 31
2.. 89

8.. 83
16.. 60
13., 49
2.. 74

5..06
.75

2.. 19
.34

1 ..91

2.. 10
. 24

3.. 10
.35

3..04
. 37

13..66
13. 47
39.. 85
48. 23
5. 00

12.. 14
7..24
4.,28
12., 34
7. 29
65..99
64. 08
5..00

2.. 34
.42
2! 20
1 .04
12. 49
8..13
3. 50
7. 61
3. 28
39..63
69. 51
5. 00

9.. 83
5..04
4. 54
10. 84
9. 77
80. 06
53. 27
5. 00

8.. 83
4. 72
3. 83
11. 88
9. 66
69. 19
55. 67
5. 00

FLE-5
52.50
17.26
8.76
4.30
4.56
5.16
1.63
1.53
. 17
.13
96.00

FLE-6
51.70
14 . 9 8
13. 01
5.23
4.26
3.42
.74
2.54
.30
.17
96.35

FLE7A
49. 44
14. 94
9. 90
7.62
12. 22
1. 92
.21
1. 12
. 14
.18
97 . 6 9

1 .34

10 .10
45..80
20 .06

7..39
1 .60
4..59
30..35
20..11

1 .28
16,, 76
32..53

11
63
32
83

1..05
4..76
3 .99
2..05

13..66
13..47
3..04

2.,68
44

3,.05
.42
4 . 53
4.. 19
1..05
.55
, 46
4.. 21
3.. 53
30.. 45
53..22
5..00

FLE7B
5 2 . 04
14 . 3 2
-

7.43
7.31
10.26
3.77
.41
1.19
. 17
. 14
97.04

NORMS
4
C
Or
Ab
An
Ne

1 .. 17

.

1 .60
15..70
33..67

3..32
29. 72
22..79

9..86
15..25
10..86
2.,95

5.
17.
14.
2.

.

.

AC
A

Ns
Wo
En
Fs
Mt
nm
ii
Ap
Fo
Fa
Di =:Wo
En
:Fs
Hy=En
:Fs
Pl ag
MgVAL
FeRAT

3..29
.40
3.,61
2..83
9..86
5..53
3..94
9..72
6.. 92
68..20
58., 94
5..00

5.. 11
2..73
2. 22
14. 90
12. 11
43. 39
56. 38
5. 00

.

.25

.

151

11..09
6., 76
3. 72
12. 27
6. 75
57. 43
65. 77
5. 00

13.
7.
4.
12.
7.
74.
63.
5.

08
76
66
12
27
29
91
00

Badwater Greenstones

Si 02
A1203
Fe203
FeO
MgO
CaO
Na20
K20
T102
P205
MnO
LOI
TOTAL
NORMS
£'■
C
Or
Ab
An
Ne

FLW-3
47. 14
15. 42

IM-1
6 0 . 81

13. 76

IM-2
IM-3A
43":73 " 4 8 . 0 2
17. 27 20. 99

IM-3B
4 4 . 8S
17.38

IM-3C
47.53
12.54

IM-4
47.21
15 . 8 0

-

-

12. 27
5. 7 6
10. 20
2.10
.66
2.25
.27
.18
96 . 2 5

14. 25
4.88
6.06
1.92
1.86
2. 01
. 27
.21
96.03

1 .04

7 .45

4..09
18,.65
32..21

11..58
17,. 11
24..68

1 . .27
16 .23
41..24

2..10
30,.57
42..54

.74
22 .33
37..44

1 . .92
20..63
24..05

4 .29
19 .40
32 .91

7..95
15..05
13..00
2 .87

2.. 14
12.,80
16..21
3.. 35

1..72
14..08
14,.71
3..43

.26
6..80
6..16
2.. 14

8..94
5..35
4,.92
2.. 85

11..38
13.. 74
17..11
3. 60

4.. 48
.67

4. 02
,67
2.. 14
.94
1 . 19
11..86
15.,02
59.,06
44. 24
5. 00

2..54
30
3. 30
3..30
26
13
12
6. 67
6. 04
58. 18
52. 71
5. 00

3..46
.40
6'.74
6..83
8.. 94
4.. 55
4. 18
.81
74
62. 64
52. 18
5. 00

4. 73
62

7. 95
4., 14
3.,58
10..91
9..42
63..34
52. 10
5. 00

3..80
.43
1 . .44
1 . .66
1 . .72
83
87
13..25
13., 84
71..76
49. 40
5. 00

-

14 . 3 6
6.05
8.76
1.79
.20
1. 8 7
. 17
.20
-

94.46

-

-

-

-

9. 21
4.43
8.49
3. 4 6
. 34
1.28
. 12
. 14
96.48

12.19
5.74
11. 54
2.52
. 12
1.74
. 16
. 19
9 6 . 43

15.35
5.25
10. 17
2.32
. 31
2.37
. 25
. 25
96. 34

10 . 6 9
9.51
8. 39
2.18
. 69
1.13
. 12
. 17
-

IM-5
48.54
15. 55

IM-6A
49.61
15. 99

-

-

12. 14
6.54
8.82
2. 21
.61
1.70
. 16
. 18

12. 23
8. 0 1
6. 82
1. 6 0
. 36
1.37
. 10
. 17

IM-7
51. 61
14. 58
12. 39
5. 45
6. 58
3. 90
1. 20
1. 47
. 16
.20

-

-

96. 45

96 . 2 6

97. 54

1 . 85
3 . 77
19 . 58
32.. 15

6 . 70
. 85
2 .23
14 .20
34 .81

7 . 34
34 . 17
19.. 40

4..20
16..29
8.. 38
2.. 51

5..25
17.,05
13..75
2.. 84

20.. 93
14..45
2.. 86

5..56
12.. 15
12..42
2., 86

2. 26
,30
6..04
3. 43
4. 20
2. 61
1 . 34
13. 68
7. 04
62. 91
67. 34
5. 00

3. 38
.40

2.. 73
.25

95. 89

2 . 23

-

/A/*
lC

Ns
Wo
En
Fs
Mt
Um
run
11

Ap
Fo
Fa
Di = Wo
En
Fs
Hy= En
Fs
Pl ag
MgVAL
FeRAT

11.
5.
6.
8.
10.
53.
44.
5.

152

38
05
29
69
82
83
21
00

5.
2.
2.
14.
11.
62.
55.
5.

25
81
27
24
48
15
52
00

20.
14.
71.
60.
5.

93
45
02
28
00

2. 89
.39
1 . . 33
1 .. 50
5. 56
2. 70
2. 76
9. 45
9. 65
36. 21
50. 48
5. 00

Hemlock Volcarries

S102
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti 02
P205
MnO
LOI
TOTAL

IM-8
49 . 9 1
20.44
5.28
6. 6 7
13. 53
1. 74
. 71
. 25
.01
. 11
98.65

IM-9
50.2*7
17. 07

KR--1
50..72
13..38

KR--2
53..51
12..55

KR--3
51..70
13.,67

KR--4
52..98
12..98

KR--5
51..80
14..27

KR--6
52..13
13..08

KR--7
50..03
13..93

KR--10
59..16
17. 47

12..91
7..73
6..28
4..00
,40
1 ..37
. 11
,18

13. 64
3..92
7. 90
2.,84
1 . 32
1 .,65
18
18

12. 55
6..11
9.,06
1 ..94
90
1 ..30
, 10
20

14.,44
4..47
6. 66
2..49
. 56
1 ..77
20
20

9. 34
7..30
8. 84
3. 17
1 . 11
1 ..10
09
.17

14. 65
4..88
6., 73
2..71
52
1 ..73
19
22

14.. 66
4..57
6.. 57
3..95
1 . 10
1 ..96
. 20
19

6. 56
2..25
3. 17
5. 52
2. 84
87
13
08

97..08

97. 69

97. 53

96.,75

97.. 19

96..84

97..16

98. 05

7 .44

6 .38

11 .16

2 .46
35,.23
18..08

8..07
24.. 87
18..21

5 .51
17..00
26 .86

3 .46
22 .03
23 .62

6 . 80
27..81
22 .21

3 .21
23 . 96
22.. 98

6 .77
34 .81
17 .73

17 .20
47 . 88
14 .87

5..68
14..31
10..90
3..00

8.. 82
10.. 10
15.. 67
3.. 15

7..94
15..76
14..87
2..90

3..99
11.. 64
16..74
3. 37

9..45
17.. 59
10.. 16
2.. 16

4..43
12..70
17..11
3 . 41

6..20
9 .04
12,. 68
3.. 40

. 16
5.. 74
7..32
1 . 50

2..71
. 27
4.,02
3..37
5..68
3..11
2., 37
11..20
8. 53
33. 92
58. 12
5. 00

3.. 24
, 44

2..56
.25

3. 52
.50

3.. 43
, 47

7.. 94
3..99
3. 77
11..77
11. 10
61. 24
53. 01
5. 00

3. 99
1.,65
2. 37
9. 99
14. 37
51. 74
41. 77
5. 00

3.. 88
. 49
1.. 97
3..04
6.. 20
2.,59
3. 63
6. 45
9. 04
33. 75
41. 94
5. 00

1 .. 69

8., 82
3. 50
5. 42
6. 61
10. 24
42. 27
39. 97
5. 00

2.. 17
. 22
88
56
9..45
5.. 67
3. 28
11. 91
6. 88
44. 41
64. 43
5. 00

-

5. 6 7
10.03
13. 76
1. 40
. 24
. 14
.01
. 14
98.73

NORMS
Q
C
Or
Ab
An
Ne
Ac
Ns
Wo
En
Fs
Mt
Hm
11
Ap
Fo
Fa
Di=Wo
=En
=Fs
Hy=En
=Fs
Pl a g
MgVAL
FeRAT

-

4.27
14. 99
46.69

1. 44
12 . 0 5
40.27

-

-

-

-

9. 01
16. 25
6.43
1. 20
. 48
. 02
. 46
.20
9. 01
5.98
2. 37
10. 27
4.07
75 . 7 0
74. 54
5.00

12. 15
24. 44
7.16
1. 29
.27
.02
.69
. 22
12. 15
8.59
2. 52
15. 85
4. 64
76 . 9 7
80.39
5. 0 0

153

8 .31

4.
1.
2.
10.
14.
48.
43.
5.

43
89
55
81
57
95
56
00

3 .31

.

. 32
. 16
.07
09
5. 67
7. 23
23. 69
44. 28
5. 00

Hemlock Volcanics

Si 0 2
A1203
Fe203
FeO
MgO
GaO
Na20
K20
Ti 02
P205
MnO
LOI
TOTAL

KR-11

KR-12

47.76
15.16

63 . 2 7
14. 22

KR-13__ KR-14
60.02
51.98

13. 07

-

-

-

12 . 2 2
7.79
9.39
2. 61
. 49
1. 0 2
. 09
.21
96 . 7 4

10. 06
7.18
6.97
4.42
.42
.93
.08
.17
97 . 7 2

7. 27
5.35
5.42
5.19
. 95
.88
. 12
.12
98.39

15.27
-

LM-1

LM-2

53.32
1 3 . 89

49.26
15 . 6 8

-

-

LM-3

-

9.60
7.14
6.27
4. 3 1
. 57
1.00
. 10
. 16
96.40

1 2 . 15
4.80
4.21
3.66
. 74
2.10
. 32
. 14
95.33

7..35
28..58
25..90

4..84
11.. 37
25..51

8.. 98
8. 02
5..73
2. 34
2. 38
25
5. 86
4. 62
8. 98
5. 03
3. 59
2. 99
2. 13
47. 54
59. 26
5. 00

10 . 0 2
6.29
9. 27
3.23
1. 19
1. 2 0
. 10
. 16
-

96.40

LM-4

"S'S"' 36'"' 46 . 3 4
11. 86 17. 69
13. 45
2.59
7.99
1. 28
. 78
2.62
. 25
. 14
96.32

-

10. 61
9.43
9.09
2.14
. 47
. 95
. 10
. 15
95. 97

LM-5

LM-6

50 . 5 6
1 3 . 03

49. 68
14. 18
13. 12
4. 87
9. 64
2.02
1. 42
1. 76
. 21
.20

-

13. 11
5.08
9.91
2.04
1. 0 3
1.67
.20
.20
96.83

9 7 . 10

5 .44

3..32

2..92
19..03
39..17

6 .35
18 .01
24 .37

8 .73
17 .79
26 .47

6..00
6..77
13..88
3., 15

3.. 14
9..05
4..76
2..49

10.. 68
13..20
15..10
3..05

9.. 14
12.. 62
14 .91
3..05

5. 22
. 62

1. , 90

3.. 31
. 49

3.. 48
.52

10. 68
4..93
5. 64
8. 27
9. 45
57. 50
47. 31
5. 00

9. 14
4.. 16
4. 91
8. 47
10. 00
59. 80
46. 24
5. 00

-

NORMS
Q
C
Or
Ab
An
Ne

6..97
3..02
23..05
29.. 44

2..56
38..58
18..28

5,.74
44..89
9..77

3..52
38.. 13
21..57

8..77
. 19
4..63
32,,81
19..91

Ns
Wo
En
Fs
Mt

7..76
12..46
9..26
2..85

7..04
15.. 54
10..18
2.. 31

7..06
13..62
8..29
1. .66

4..28
13..96
8..62
2. 24

12..66
13..15
2. 87

2. 02
.22
5..46
4..47
7..76
4..28
3., 18
8.. 18
6.,08
56..08
59. 63
5..00

1. . 82

1. .71

Ap
Fo
Fa
Di =Wo
En
:Fs
En
:Fs
Pl a g
MgVAL
FeRAT

. 19
2..04
1..47
7. 04
4..06
2..66
11..48
7. 52
32..15
62. 32
5..00

.29

99
25
3..25
2..21
4. 28
2. 52
1 . 56
11. 44
7. 07
36. 14
63. 28
5. 00

22..66

Afy
AC

E
N

n

Um
run
ii

7. 06
4..17
2..54
9..45
5..75
17.,88
63. 04
5..00

1.

4. 22
80

12.
13.
37.
47.
5.

66
15
77
79
00

154

6. 00
2..03
4. 15
4. 74
9. 72
69. 18
30. 85
5. 00

.25
10.. 96
6. 35
3. 14
1 . .94
1. 02
7. 11
3. 73
67. 30
67. 32
5. 00

Hemlock Volcanics

LM-7

S102
"4 8 . 64
A1203 14 . 1 2
Fe203
13 . 8 8
FeO
MgO
5.62
CaO
9.11
Na20
2.59
. 66
K20
Ti02
1.74
P205
.21
. 20
MnO
LOI
TOTAL 96 . 7 7
-

LM-8

'" T T 5 6
14. 44
14. 51
7. 41
3.12
. 76
2. 93
1.89
. 27
. 32
93.15

LM-9

LM-10

4 8 . 24 - j g - g g 15. 12 14 . 7 8
11. 97 1 2 . 9 0
5.79
6.09
10. 26
8 . 38
1. 94
2.80
1. 22
.99
1 . 67
1.55
.24
. 18
.20
. 19
-

LM-11

LM12A

LM-14

LM-15

LM-16

46.97
15. 46

4 7 . 6 6 - S 3 . 7 ? r 46 A 1
14 . 7 2 1 1 . 82 14. 79

66.3 6
13. 54

48 . 1 7
1 5 . 26
10. 24
8. 49
10. 98
2.09
.49
. 83
.07
. 16

-

-

13. 11
6.22
10. 67
1.57
. 80
1.55
. 19
. 19

13.20
7.30
3.25
2.42
2.09
1.89
.27
. 20

LM-13

-

1 4 . 58
2.54
5.67
2.72
2.09
2.34
. 43
. 20

-

12 . 2 4
8.40
6. 23
3.46
1.27
2.19
. 23
. 16

-

12.55
6.60
8.23
3.64
1.08
1. 11
. 12
. 17

-

-

-

-

-

-

-

-

96 . 6 5

96.85

96.73

9 3 . 00

96 . 1 4

95.64

97. 40

96.78

.62

11 .30
13 .00
24..22
14..60

7 . 93
30 . 92
22 . 25

6 . 62
31 . 94
18 .06

3 .02
18 .42
32 . 10

NORMS

‘"<5
c

.87

Or
Ab
An
Ne

4..07
22..90
26..07

8..21
5..43
18..81
6..99
14..90

.87
7..53
17.. 15
30..24

6.. 10
24,.72
25..91

4 .94
13.. 88
34..24

2..20
3 .49
13..43
22..26
15..61

8.. 23
14. 63
16..03
3..23

20..05
17..52
3..52

8..89
15.,06
13..58
2.. 79

6..78
14..21
13..47
3..00

8..25
16., 18
15..30
3..06

19.. 76
15.,45
3. 20

5..03
6..66
16..05
3..42

3,. 67
4.. 12
2.. 45
2.. 88

9.. 80
9..09
8..08
2.. 90

10 .09
16.. 35
9..35
2.. 38

3.,45
.52

3.,90
.69

3. 31
,59

3.,07
.44
1 ., 13
1 ..18
6. 78
3..40
3. 23
10. 81
10. 24
51. 18
52. 24
5. 00

3. 08
. 47

3. 90
.69

4.. 68
1 ..07

4., 39
. 57
12.,59
8. 23
3..67
2.. 19
1 . 30
1 . 94
1 . 15
41. 95
61. 40
5. 00

2. 19
. 29
5. 57
5. 46
9. 80
5. 05
4. 49
4. 04
3. 59
36. 12
54. 93
5. 00

1 ., 64

AC

Ns
Wo
En
Fs
Mt
P
m
nm

n

<<

33

Ap
Fo
Fa
Di =Wo
En
:Fs
En
:Fs
Pl ag
MgVAL
FeRAT

8. 23
3.. 88
4..25
10..75
11..77
53. 24
48. 41
5.,00

20. 05
17.,52
68. 08
54. 20
5.,00

8.
4.
4.
10.
9.
63.
52.
5.

89
56
11
51
47
81
85
00

8. 25
4.. 15
3. 92
12. 03
11. 38
71. 16
52. 37
5. 00

155

19.
15.
41.
56.
5.

76
45
22
17
00

5. 03
1 . 53
3. 70
5. 12
12. 35
37. 60
28. 76
5. 00

. 17
3..98
2.,51
10. 09
6. 08
3. 47
10. 27
5. 87
63. 53
65. 77
5. 00

Hemlock Volcarries

LM-17

HiBT
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti 02
P205
MnO
LOI
TOTAL

46 . 1 6
18 . 1 7
9.36
7.54
11 . 0 0
2.66
. 17
1.02
. 12
. 12

LM-18
41.2&

14. 63
11. 45
9. 91
10. 34
1. 4 9
. 19
. 84
.06
.20

LM19A

LM19B

LM-20

KJ-1

KJ-2

KJ-3

KJ-4

KJ-5

4d.fc5
14 . 4 2
11. 64
8.55
10 . 0 3
2.18
. 15
. 92
. 07
. 19

4S. f i l
1 4 . 87
12 . 0 7
8.57
8.40
3.00
. 13
.97
.08
.20

63.63
12. 76
12 . 6 7
6.02
5.15
2.11
2.55
1.60
. 19
. 14

53.36
17 . 1 4
12. 35
3. 2 4
1.42
3. 3 5
3.88
1. 21
. 22
. 13

46. 96
13. 57

47.36
16. 30

46 . 2 4
17. 33

48.43
14 . 8 5
12. 98
5.90
5. 63
2.22
3.83
2. 44
. 25
.21

-

-

-

-

96.31

96.39

96.70

96.90

-

-

-

15 . 6 7
3.65
6.52
. 49
3.63
2.08
. 28
.24

10.22
7.12
9.68
2. 98
. 84
1. 04
. 09
. 19

-

9.56
7.55
10. 73
2.04
. 61
. 89
. 09
. 15

-

-

-

-

96. 88

96.29

93.09

96.42

97.19

96. 73

-

7 .57

5 .63
23 .35
4 . 51
26..24

5 . 19
26 .37
29 .93

3 .74
17 .90
37 .66

23 .64
19 . 62
20 .10

NORMS
Q
C
Or
Ab
An
Ne
AC
Ns
Wo
En
Fs
Mt
Urw
nm
11

Ap
Fo
Fa
Di =Wo
En
Fs
Hy= En
Fs
Plag
MgVAL
FeRAT

1..05
23..55
38..85

1,.18
13..20
34..21

.93
19..25
30..39

.80
26 .45
27 .85

15..71
18.. 62
18..58

5 .60
5..64
24..05
29..73
5..88

7..27
5..79
3..26
2.. 18

7..97
22..95
12..74
2.. 67

8..80
20..67
13..39
2.. 71

6..28
14.. 69
9..83
2..81

2..83
15. 63
14..50
2., 95

8.. 46
14.,81
2., 89

2..91
9.. 89
18..67
3..80

8..22
6,. 97
4..62
2.. 38

7 .06
15..95
9.. 41
2,. 21

3 .03
7.. 60
6..75
3..02

2.,03
30
9. ,71
6. 02
7. .27
4. 40
2. 48
1. 39
78
62. 26
65. 12
5..00

1..67
.15
2. 02
1. 24
7..97
4.,84
2.,69
18. 11
10. 05
72. 15
66. 73
5. 00

1 ..82

1..92
.20
5 !.29
3.. 90
6..28
3..59
2.. 40
11..09
7 ., 42
51 . 28
62.. 20
5..00

3., 17
47

2..41
. 55

4.. 30
72

2..07
.22
a. . 11
5. 93
8. 22
4. 72
3. 13
2. 25
1 . 49
53. 16
61. 75
5. 00

1 . 75

4., 84
.62
5'., 43
5..31
3.,08
1 . 59
1 . 41
6. 01
5. 34
50. 60
51. 30
5. 00

. 17
1. 09
78
8.,80
5..09
3. 30
15..58
10. 09
61. 22
62. 99
5. 00

2.
1.
1.
14.
13.
49.
52.
5.

83
43
33
20
17
94
40
00

156

8.
14.
16.
37.
5.

46
81
51
81
00

2.
1.
1.
8.
16.
85.
35.
5.

91
03
95
86
72
32
06
00

.22
2. .48
1..62
7..06
4. 21
2 49
11. 74
6. 93
67. 79
64. 67
5. 00

G ranites

Mona S c h i s t s

£->i02
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti 02
P205
MnO
LOI

I21AL-

KJ-8
KJ-6
4^. 66 TT.'SV
13 . 3 8 15. 25
13. 41 13. 78
3.65
10 . 7 2
8. 11
6.85
3. 64
2.98
1.19
. 12
3.14
2. 43
. 46
. 17
. 19
. 19
95 . 9 3 9 7 . 0 8

MQ-5
47 . 7 3
15. 61
11. 28
7.30
11. 99
1. 78
. 42
.90
.06
. 20
97 . 2 7

MQ-6
51.26
16.04
9.12
6.82
5.09
5.09
. 43
. 73
. 06
. 30
94.94

MQ-7
50.16
15. 11
11 . 7 2
6.57
9. 10
1. 75
.85
1. 23
. 14
.21
96 . 8 4

NS-2
49.11
15 . 3 7
11. 77
6.89
10 . 9 6
1. 91
.84
. 88
.07
. 22
98.02

NG-1
47.44
1 5 . 99
11. 90
8. 30
9.22
2.65
. 31
. 95
.07
.21
97-JL4.

CP-1
69.26
15. 57
3.47
1. 80
1.89
2.93
3. 15
. 44
. 13
.04
-

SQ-1D
74 . 6 5
14. 46
.72
. 82
3. 44
6. 24
.03
.01
.01
-

WF-6C
74.09
14.09
1. 36
. 35
1.22
4.53
3.49
. 15
. 05
.02
-

32..58
4..28
18..91
25., 19
8..66

28. 53
. 58
36 . 7 6
29 . 0 1
3.99

30 . 92
. 77
20 . 78
38 . 62
5 . 77

NORMS
Q
C
Or
Ab
An
Ne
AM
AC
Ns
Wo
En
Fs
Mt
rt_
H
ra
n
Ap
Fo
Fa
Di =Wo
En
Fs
Hy=En
Fs
Plag
MgVAL
FeRAT

4.. 80
.75
26! 57
24. 00

7. 32
32.,08
22. 66

2..58
15..62
34..61

2..70
45.. 70
20..85

5..24
15..44
32..17

5.. 11
16..64
31..80

1..91
23..33
32..06

4..44
12.. 16
6.. 18
3., 15

6..73
5..95
8..43
3. 20

11.. 14
16,.25
11..96
2.. 61

2..31
6..61
4. 31
2., 16

5..82
17..06
13..99
2. 72

9..90
17., 22
14.. 13
2.,70

6..28
11..45
7..82
2..76

4., 86
42
11.. 20
6..27
4.,44
2..77
1..41
9. 39
4., 77
47.. 46
64.. 94
5..00

6. 21
1.. 13
2.,47
3..85
6. 73
2.. 80
3., 96
3. 15
4. 46
41. 40
38. 03
5.,00

1.. 77
. 15
1.. 83
1..48
11.. 14
6.. 17
4.. 54
10..08
7.. 42
68.. 90
59.. 99
5..00

1. 47
.15
7. 99
5..74
2. 31
1 ,33
87
5. 28
3. 44
31. 33
63. 41
5..00

2. 43
.35

1.. 72
.17
31
.28
9! 90
5.. 27
4. 32
11. 95
9. 81
65..65
57. 56
5..00

1..88
. 17
7. 05
5.. 30
6. 28
3., 57
2. 44
7. 87
5. 38
57. 88
61. 78
5. 00

-

.

5. 82
3.. 10
2. 54
13. 96
11. 45
67. 58
56. 50
5.,00

157

4.. 55
3..87
. 79

. 89
. 16

. 88
1 .55
.31

.85
.31

. 06
. 02
. 89
12 . 0 9
5. 0 0

, 29
.12

4. 55
3. 87
25..59
54. 59
5. 00

.

1.
13.
37.
5.

88
55
00
36
00

S102
A1203
Fe203
FeO
MgO
CaO
Na20
K20
Ti 02
P205
MnO
LOI
TOTAL

WL-3
72.68
11. 51
4.00
. 49
1.06
2.76
4.30
. 56
. 09
. 06
-

KR-15
71.13'
12. 30
5. 18
. 92
1. 07
2. 81
4.20
. 66
. 10
.07
-

96 . 9 1

98 . 4 4 :

36 . 0 8
. 63
26.30
24. 18
4.84
-

33 . 3 9
1. 45
25.32
2 4 . 25
4.75
-

NORMS
Q
C
Or
Ab
An
Ne
Ac
Ns
Wo
En
Fs
Mt
Hm
11
Ap
Fo
Fa
Di=Wo
=En
=Fs
Hy=En
=Fs
Plag
MgVAL
FeRAT

-

1.26
4. 48
. 92
1. 10
. 22
-

-

2. 34
5. 81
1. 18
1. 28
.24
-

-

-

1.26
4.48
16 . 6 7
22. 11
5.00

2. 34
5. 81
16. 37
29. 16
5. 00

158

A PPE N D IX 2: T race and R a re E arth elem ents compositions.

Dikes

Sample

FO-1

MR-1

M R-2

GR-1

G R-2

G R -3A

GR-3

Ni

46.4

30.2

39.8

214.3

59.4

190.3

173.8

Cu

227.9

41.4

61.0

23.4

16.6

1 2 .2

21.9

Zn

82.5

117.4

1 0 2 .1

112.3

120.3

86.5

77.0

Rb

10.4

27.6

17.4

51.7

33.6

4.5

28.8

Sr

87.7

238.4

230.5

260.5

342.2

115.4

172.7

Y

27.8

29.8

27.3

24.4

32.6

14.9

17.6

Zr

155.7

179.3

1 1 1 .2

109.1

229.6

70.1

56.7

Nb

20.4

18.2

8.9

21.7

16.7

5.6

2 .8

Ba

255.5

365.0

155.2

384.2

554.3

18.6

93.4

La

15.38

29.93

9.89

14.33

32.56

10.96

8.43

Ce

23.14

24.16

12.82

35.25

69.52

26.94

24.83

Sm

5.13

6.89

4.19

3.53

6 .8 8

3.54

2.53

Eu

1 .8 6

1.97

1.83

1.33

2.14

1.43

1.37

Tb

1 .0 0

0.96

1.04

0.57

0.81

0.77

0.73

Yb

2.60

2.51

2.70

1.91

2.69

2.37

2.27

Lu

0.46

0.46

0.51

0.30

0.44

0.35

0.34

Hf

3.54

3.50

3.48

2 .8 8

6 .0 1

6 .1 1

4.64

Th

8.30

10.43

10.18

1 .8 6

6.05

7.00

4.84

Cr

236.9

119.6

170.9

380.3

154.3

603.9

602.9

Sc

45.0

38.4

43.8

24.0

43.8

34.9

32.3

F /F + M

0.623

0.768

0.700

0.556

0.710

0.534

0.547

R b /S r

0.119

0.116

0.075

0.198

0.098

0.039

0.167

K /R b

1109

321

367

246

272

572

228

K /B a

45.2

24.3

41.2

33.1

16.5

138.3

70.2

159

Dikes

Samole

GR-4

MG-1

NRP-2

NRP-3

NRP-5

IP-1

183.5

96.0

170.7

69.3

IP-2

Ni

0 .0

0 .0

Cu

28.0

13.9

12.5

0.4

1 1 2 .0

73.6

134.3

Zn

133.9

183.3

164.9

125.8

93.7

8 8 .0

57.2

Rb

19.3

87.0

56.3

283.8

55.6

7.1

8 .2

Sr

379.1

105.8

273.5

235.9

229.8

270.1

191.0

Y

40.0

35.6

54.5

55.3

26.5

18.3

21.7

Zr

155.7

179.3

1 1 1 .2

109.1

229.6

70.1

56.1

Nb

57.0

29.3

65.6

68.7

1 0 .1

7.2

3.7

Ba

484.8

1015.5

2130.5

1177.9

361.5

213.7

154.4

La

39.51

55.31

87.11

46.40

13.18

11.77

5.49

Ce

115.51

116.10

146.38

91.55

23.47

28.51

18.03

Sm

8.03

10.81

16.19

6 .8 8

3.82

3.18

2.55

Eu

4.12

2.99

4.59

2.60

1.61

1.27

0.95

Tb

0.71

0.91

1.04

0.69

0.89

0.51

0.53

Yb

2.57

2.30

2.56

2.27

2.34

1.89

1.89

Lu

0.36

0.41

0.46

0.30

0.39

0.31

0.39

Hf

11.09

3.87

4.84

6.08

6.50

2.63

2.33

Th

5.61

9.80

11.70

4.35

9.38

1.87

1.42

Cr

44.5

89.3

93.5

168.9

170.2

158.3

229.6

Sc

32.9

27.2

29.9

19.9

37.3

30.8

40.9

F /F + M

0.761

0.822

0.867

0.582

0.649

0.590

0.623

R b /S r

0.051

0.822

0.206

1.203

0.242

0.026

0.043

K /R b

624

467

333

129

158

538

445

K /B a

24.8

40.0

31.1

24.3

17.9

23.7

0 .0

8 .8

160

Dikes

Sample

IP-3

IP-4

IP-5

Ni

93.8

151.7

219.8

Cu

69.9

44.2

75.6

Zn

93.8

70.6

Rb

26.6

Sr

IP - 6

WL-1

WL-2

WL-4

1 0 0 .8

92.4

12.7

228.4

0 .0

183.6

69.0

153.8

78.5

1 0 1 .6

104.4

19.2

16.5

13.1

1 .6

135.8

23.7

134.7

231.6

190.2

62.7

136.2

59.1

84.5

Y

18.8

17.6

17.8

40.8

16.9

34.9

29.1

Zr

90.7

57.2

54.9

313.2

52.4

50.7

144.6

Nb

8.5

7.7

5.9

60.2

6.3

5.9

14.3

Ba

411.9

363.4

195.7

123.6

25.6

279.6

387.8

La

10.46

7.04

7.78

52.90

13.40

6.90

17.97

Ce

25.93

9.58

9.72

110.36

18.86

12.53

23.57

Sm

3.17

1.54

1.64

13.72

1.97

1 .8 8

5.21

Eu

1 .1 0

1.24

1.26

4.17

1.44

0.81

1.99

Tb

0.56

0.77

0.77

0.80

0.91

0.38

1.05

Yb

1.48

2 .1 1

2 .1 1

2.08

2.42

1.77

2.75

Lu

0.19

0.39

0.38

0.39

0.40

0.30

0.48

Hf

2.41

2.51

2.51

3.72

6 .2 2

1.17

3.66

Th

2.05

4.64

5.21

9.30

8.31

1 .0 1

11.13

Cr

84.3

263.1

329.3

60.7

223.6

251.9

143.0

Sc

27.9

33.7

33.8

19.3

41.4

39.3

41.8

F /F + M

0.620

0.551

0.512

0.809

0.570

0.670

0.740

R b /S r

0.197

0.083

0.087

0.209

0 .0 1 2

2.298

0.280

K /R b

655

367

362

779

2023

230

361

K /B a

42.3

19.4

30.5

82.6

126.4

111.9

0 .0

161

2 1 .6

2 2 .0

Dikes

Sample

M Q-1A

MQ-1B

MQ-1C

MQ-4

RQ-1

RQ -2

Ni

48.1

51.9

57.2

61.5

40.8

1 .2

92.1

Cu

46.9

6 6 .0

54.6

232.1

19.9

8 .1

142.3

Zn

1 1 2 .2

114.1

117.6

68.9

1 1 0 .1

155.1

98.8

Rb

24.6

40.8

64.2

1 0 .2

28.2

46.7

35.2

Sr

516.1

388.3

229.2

146.7

325.8

248.0

138.2

Y

20.9

22.9

26.2

16.5

2 0 .1

53.8

25.9

Zr

138.3

125.0

1 2 1 1

64.6

128.0

380.6

91.7

Nb

4.0

5.0

7.6

3.0

15.3

70.3

5.4

Ba

941.5

491.8

558.1

157.7

614.6

1197.2

163.7

La

18.73

15.78

16.32

6.09

2 0 .0 2

76.08

8.44

Ce

20.65

20.65

20.40

13.07

21.13

143.81

24.41

Sm

5.23

4.99

4.70

2.16

4.87

14.70

3.71

Eu

1.85

1.78

1.75

0.72

2.31

4.52

1.16

Tb

0.90

0.90

0.90

0.41

0.84

1.06

0.34

Yb

2.35

2.35

2.40

1.94

2.69

2.58

2.36

Lu

0.42

0.41

0.42

0.32

0.34

0.46

0.38

Hf

2.03

3.15

3.13

1.48

6.50

4.68

1.87

Th

9.41

9.28

9.34

1.27

7.59

11.56

1.57

Cr

135.4

135.4

138.2

117.8

134.7

96.7

95.4

Sc

36.2

36.1

36.3

38.4

34.2

31.3

40.6

F /F + M

0.717

0.715

0.706

0.538

0.670

0.848

0 .6 8 8

R b /S r

0.048

0.105

0.280

0.070

0.087

0.188

0.255

K /R b

402

305

181

521

533

297

245

K /B a

10.5

25.3

33.7

24.4

2 0 .8

162

1 1 .6

SQ-1A

52.7

Dikes

Sample

SQ-1B

Ni

85.9

Cu

SQ-1C

SQ-2A

SQ-2B

SQ-3A

SQ-3B

NSV/-1

1 0 1 .2

94.9

55.0

61.8

80.5

87.0

160.9

130.3

203.2

108.1

126.8

139.8

15.6

Zn

130.1

99.9

135.9

96.4

131.2

127.2

90.5

Rb

48.2

25.0

78.5

26.9

25.0

15.0

2 1 .1

Sr

125.4

157.3

1 0 2 .2

335.1

107.8

139.2

350.3

Y

26.9

24.5

42.2

35.9

30.2

25.0

15.5

Zr

87.8

89.5

236.8

236.8

129.6

104.8

82.8

Nb

5.8

6 .2

17.1

10.3

8 .1

5.8

6.7

Ba

124.1

190.4

789.9

2008.4

407.7

222.7

566.3

La

9.41

1 0 .0 0

20.06

20.99

12.99

10.03

17.85

Ce

27.29

23.93

50.50

49.94

31.14

27.13

25.47

Sm

3.79

3.51

8.16

9.18

4.69

4.43

4.72

Eu

1 .2 2

1.17

2.44

2.90

1.3"

1.30

2 .0 0

Tb

0.65

0.61

0.72

0.85

0.45

0.52

0.70

Yb

2.80

2.60

3.19

3.31

3.06

2.70

2.23

Lu

0.41

0.44

0.45

0.47

0.52

0.46

0.36

Hf

2.73

2 .1 0

6 .1 2

6.55

3.28

2.76

5.07

Th

1.90

1.89

2.46

3.18

2.36

1.71

4.18

Cr

83.8

109.1

1 1 1 .0

119.2

93.0

103.3

340.4

Sc

40.7

39.7

33.9

36.1

35.8

40.2

40.6

F /F + M

0.691

0.669

0.771

0.801

0.679

0.654

0.571

R b /S r

0.384

0.159

0.768

0.801

0.679

0.654

0.571

K /R b

152

239

575

364

335

450

673

K /B a

58.9

31.4

57.2

4.9

33.2

17.6

163

2 0 .6

Dikes

RP-2A

RP-2B

RP-3

RP-4

RP-5

0 .0

158.2

69.1

6 6 .2

39.6

31.8

7.5

85.1

46.1

65.7

35.0

52.7

1 1 2 .6

95.4

103.6

119.7

109.3

121.7

22.7

49.0

63.3

14.5

57.0

101.4

156.4

215.9

166.5

175.5

119.2

301.9

371.8

49.5

22.3

19.1

26.3

27.6

36.8

Sample

NS-1

RP-1

Ni

50.7

Cu

14.2

Zn

8 8 .2

Rb
Sr

2 1 .8

Y

2 1 .1

Zr

62.0

309.3

66.4

76.0

89.0

167.2

276.3

Nb

3.1

84.4

3.8

3.2

1 0 .1

23.2

42.7

Ba

227.5

925.8

109.6

55.0

130.8

299.4

607.8

La

7.01

62.62

9.90

9.39

12.16

22.56

62.41

Ce

11.99

174.54

24.17

24.56

20.45

26.65

119.24

Sm

1.77

10.48

3.23

3.36

3.88

6.63

9.39

Eu

1.60

6.07

1.19

1.48

2.15

2.90

2.69

Tb

1.05

0.74

0.71

0.75

0.95

0 .8 6

0.85

Yb

2.76

2.85

2 .2 0

2.41

2.44

2.25

2.65

Lu

0.47

0.38

0.34

0.37

0.40

0.36

0.34

Hf

3.24

14.10

3.75

5.22

6.78

6.92

7.48

Th

10.31

8.05

4.58

5.75

9.19

8.33

10.43

Cr

158.7

43.8

478.7

127.9

216.7

140.1

95.9

Sc

48.1

37.6

33.9

32.9

38.7

32.6

27.4

F /F + M

0 .6 6 6

0.836

0.516

0.676

0.644

0.682

0.700

R b /S r

0.145

0.227

0.380

0.083

0.183

0.189

0.273

K /R b

336

288

1 2 2

384

228

233

151

K /B a

33.6

15.2

70.4

1 0 1 .1

38.1

44.4

25.3

1 64

Dikes

Sample

NG-2

NS-3

WF-1

WF-2

Ni

60.3

440.3

33.4

39.5

Cu

65.2

205.9

87.8

Zn

8 6 .1

102.9

Rb

13.6

Sr

WF-4

WF-5

0 .8

28.8

45.7

71.9

29.0

6 8 .2

92.0

121.4

115.6

113.0

99.6

114.6

1 1 .2

35.1

47.9

63.9

79.6

45.7

358.8

1 2 0 .2

185.2

255.8

146.4

28.9

240.6

V

18.9

15.9

31.8

28.6

43.2

39.9

26.9

Zr

109.4

50.1

167.0

143.1

249.9

216.8

113.4

Nb

9.3

3.2

2 0 .6

13.3

27.5

29.4

8.9

Ba

228.3

82.4

409.4

632.2

1186.4

714.6

271.8

La

14.96

4.64

22.14

23.09

35.60

29.90

14.47

Ce

28.42

9.96

56.61

48.97

90.01

84.79

36.34

Sm

4.45

1.37

6.29

4.88

8.54

8.44

4.11

Eu

2.61

1.32

1 .8 8

1 .6 6

2.43

1 .8 6

1.29

Tb

0.75

0.82

0.74

0.76

1 .2 1

1 .2 2

0 .6 6

Yb

2.41

2.15

2.90

2.39

3.83

3.39

1.93

Lu

0.37

0.37

0.44

0.40

0.52

0.46

0.36

Hf

6.96

5.89

4.42

3.99

7.12

6.55

2.99

Th

5.24

6 .2 2

5.06

6 .2 1

11.06

9.99

2.74

Cr

301.5

243.0

40.5

54.4

6.9

9.3

6 6 .0

Sc

34.2

36.4

40.0

35.3

30.2

43.3

45.0

F /F + M

0.605

0.525

0.754

0.709

0.801

0.777

0.703

R b /S r

0.038

0.093

0.190

0.187

0.436

2.754

0.190

K /R b

323

341

312

383

436

558

216

K /B a

19.3

46.3

26.8

29.0

23.5

62.1

36.3

16 5

WF-3

Dikes

Badwater Greenstones

Sample

W F- 6 A

W F- 6 B

W F-7A

WF-7B

CF-1

CF-2

Ni

38.4

45.2

144.4

65.4

125.4

24.6

Cu

172.9

161.8

140.4

107.5

35.4

59.2

Zn

124.5

119.5

113.6

99.6

90.1

108.3

Rb

46.3

21.4

15.2

32.7

3.2

15.3

Sr

188.9

167.7

617.8

216.1

255.2

445.4

Y

33.1

28.5

24.4

23.2

18.6

28.0

Zr

122.9

1 1 2 .8

288.5

91.6

1 1 0 .8

185.9

Nb

18.2

16.9

22.7

1 2 .6

1 0 .8

9.8

Ba

339.0

293.4

253.4

535.1

76.4

243.6

La

19.15

16.06

40.71

12.85

11.32

28.84

Ce

25.31

25.22

101.26

22.30

26.83

63.39

Sm

5.31

5.03

10.24

3.27

3.55

6 .0 2

Eu

2.04

1.97

3.13

2.34

1 .1 2

1 .8 8

Tb

1.14

1.14

0.84

1 .0 2

0 .6 6

0.83

Yb

2.95

2.90

2.15

2.67

1.85

2.62

Lu

0.52

0.52

0.36

0.47

0.33

0.43

Hf

3.72

3.70

7.82

3.31

2.65

4.56

Th

11.45

11.80

8.81

10.27

3.85

7.12

Cr

175.0

192.3

279.2

181.0

344.9

22.3

Sc

46.7

50.6

27.4

44.2

37.0

36.1

F /F + M

0.754

0.735

0.628

0 .6 6 6

0.581

0.777

R b /S r

0.245

0.128

0.025

0.151

0.013

0.034

K /R b

192

248

349

284

882

445

K /B a

26.2

18.1

17.4

36.9

27.9

2 1 .0

166

Badwater Greenstones

Sample

CF-3

CF-4

CF-5

CF - 6

FLE-2

FLE-3

FLE-4

Ni

44.2

48.1

52.0

47.0

93.7

151.0

50.2

Cu

100.9

132.9

36.3

80.0

187.7

136.5

57.2

Zn

107.1

96.6

91.4

109.5

63.9

99.3

91.5

Rb

1 .0

1.3

0 .0

12.5

1 .1

2.3

9.5

Sr

442.4

425.5

304.3

204.9

524.0

207.7

115.3

Y

20.4

19.8

19.6

23.5

18.9

20.3

Zr

117.8

113.6

98.2

1 1 0 .0

108.9

1 0 2 .8

134.4

Nb

6 .8

5.7

7.2

10.3

4.0

1 0 .1

1 2 .8

Ba

38.6

30.4

38.0

896.5

35.3

57.0

113.1

La

15.11

11.74

11.56

15.90

8.76

10.35

13.95

Ce

30.75

27.80

24.50

28.73

22.69

27.49

29.91

Sm

3.50

3.52

3.32

3.99

3.39

3.76

3.24

Eu

1.23

1.19

1.23

2.32

1.17

1.23

1 .2 2

Tb

0 .6 6

0.61

0.47

0.84

0.52

0.58

0.60

Yb

2.32

2.04

1.72

2.71

1.80

2 .1 2

1.80

Lu

0.42

0.37

0.36

0.42

0.37

0.38

0.36

Hf

2.56

2.40

2.35

9.70

2 .6 6

2.93

3.46

Th

3.50

3.61

2.52

9.70

2 .6 6

1.83

4.82

Cr

51.5

51.5

77.6

117.7

258.1

300.8

64.1

Sc

44.3

44.2

45.4

39.7

35.2

39.1

34.5

F /F + M

0.714

0.715

0 .6 8 6

0 .6 8 8

0.693

0.621

0.645

R b /S r

0 .0 0 2

0.003

0 .0 0 0

0.061

0 .0 0 2

0 .0 1 1

0.082

2 0 .6

K /R b

581

575

0

611

604

938

472

K /B a

15.1

24.6

8.7

8.5

18.8

37.9

39.6

167

Badwater Greenstones

Sample

FLE-5

FLE-6

FLE7A

FLE7B

FLE-8

FLE-9

FLW-1

Ni

56.1

23.8

91.2

99.4

73.9

8609

134.9

Cu

45.6

0 .1

60.8

57.8

8 6 .1

65.4

163.9

Zn

114.2

127.0

73.0

73.3

75.8

71.3

111.9

Rb

34.8

12.5

1 .8

2.3

8.3

8 .1

7.5

Sr

150.0

192.2

341.5

150.7

230.7

196.8

238.1

Y

29.6

34.2

18.1

18.6

17.4

18.5

20.9

Zr

130.7

210.9

92.4

88.4

80.4

78.2

1 0 2 .2

Nb

1 0 .1

25.1

8 .6

1 1 .8

7.5

10.3

8 .8

Ba

506.0

523.1

8 8 .1

190.2

1 2 1 .1

1 1 2 .1

128.0

La

31.73

40.88

1 0 .1 2

13.99

10.46

22.31

10.73

Ce

71.07

102.45

27.59

31.39

26.48

52.38

26.97

Sm

4.05

7.70

3.23

3.29

3.33

6.59

3.36

Eu

2 .1 2

2.70

2.08

0.99

1.92

2 .1 2

2.26

Tb

0.67

1 .0 2

0.77

0.58

0.73

0.74

0.73

Yb

2.33

2.64

2.38

2 .1 1

2.33

2.46

2.41

Lu

0.38

0.13

0.41

0.36

0.40

0.40

0.40

Hf

5.65

3.74

5.54

2.17

4.99

7.04

5.97

Th

3.40

11.85

4.87

3.63

5.28

6.06

4.02

Cr

135.6

128.0

368.1

315.7

320.4

109.5

323.5

Sc

33.0

42.6

35.5

42.6

36.3

35.8

33.6

F /F + M

0.674

0.716

0.569

0.509

0.551

0.571

0.673

R b /S r

0.232

0.065

0.005

0.015

0.036

0.041

0.031

K /R b

389

491

968

1480

420

492

376

K /B a .

26.7

11.7

19.8

17.9

28.8

35.5

168

2 2 .0

Badwater Greenstones

Sample

FLW-2

FLW-3

IM-1

IM-2

IM-3A

IM-3B

IM-3C

Ni

118.1

84.0

49.3

43.1

58.2

67.5

32.9

Cu

119.8

167.6

6 8 .0

201.3

159.8

111.3

248.9

Zn

8 6 .8

92.3

1 2 1 .0

94.6

62.2

93.6

127.6

Rb

6.7

7.0

37.8

2 .2

3.2

2 .0

5.6

Sr

188.6

279.7

204.6

370.9

263.4

244.7

216.9

27.5

33.7

24.6

18.1

20.3

30.0

Y

2 1 .6

Zr

96.1

16.3

18.3

1 1 .0

13.2

9.8

155.6

Nb

9.9

16.3

18.3

1 1 .0

13.2

9.8

19.0

Ba

279.6

544.0

1340.5

50.2

63.9

93.9

160.1

La

10.38

17.93

27.58

17.00

10.89

16.04

14.31

Ce

27.23

30.49

33.72

43.15

19.98

26.77

33.35

Sm

3.35

5.45

7.21

4.65

2.94

6.24

3.15

Eu

2.23

2.94

2.58

1.80

1.63

2.33

2.87

Tb

0.78

0.83

0 .8 8

0 .8 6

0.40

0.69

0.99

Yb

2.49

2.65

2.64

1.94

1.81

2.35

2.91

Lu

0.37

0.39

0.39

0.40

0.26

0.35

0.45

Hf

6.40

9.40

5.48

3.47

2 .2 1

2.95

3.66

Th

5.66

7.69

7.38

4.26

1.94

2.59

3.20

Cr

290.1

197.3

148.8

123.4

163.9

244.1

172.0

Sc

31.2

33.7

33.4

47.8

27.0

50.7

31.1

F /F + M

0.652

0.684

0.748

0.706

0.679

0.683

0.748

R b /S r

0.036

0.025

0.185

0.006

0 .0 1 2

0.008

0.026

K /R b

458

783

408

755

882

498

459

11.5

33.1

44.2

K /B a

1 1 .0

1 0 .1

1 69

1 0 .6

16.1

Badwater Greenstones

Sample

IM-4

IM-5

IM - 6 A

IM-7

IM - 8

IM-9

KR-1

Ni

280.8

1 1 0 .8

154.2

36.4

90.6

247.6

55.2

Cu

124.6

176.3

137.6

48.4

3.9

1 .8

38.5

Zn

75.4

94.5

82.3

98.9

50.9

46.4

83.6

Rb

1 2 .2

7.2

5.0

1 2 .6

17.9

7.9

1.9

Sr

183.2

185.4

161.3

188.4

62.9

59.2

Y

18.8

22.9

19.8

25.2

11.9

1 0 .0

18.8

Zr

81.8

109.9

81.8

137.5

17.8

1 2 .1

72.4

Nb

12.7

15.8

12.5

25.8

2.7

2 .0

7.4

Ba

253.2

190.5

121.3

537.9

0 .0

0 .0

38.7

La

18.27

16.62

11.36

9.46

6.74

9.50

5.68

Ce

20.50

25.40

24.84

30.24

7.85

18.64

14.74

Sm

3.45

2.96

5.15

0.75

0.34

5.11

2.87

Eu

1.60

1.58

1.99

2.05

0.34

1.27

0.78

Tb

0.42

0.65

0 .6 6

0.81

0.53

0.46

0.60

Yb

1.83

2.34

2.30

2.48

1.92

1.82

1.99

Lu

0.28

0.35

0.36

0.38

0.31

0.29

0.33

Hf

5.22

5.06

4.59

7.47

5.29

4.97

2.27

Th

2 .0 0

3.07

2.78

6 .0 0

1.26

2 .0 1

1.49

1 2 0 .1

Cr

179.2

228.6

272.0

133.3

283.1

420.0

64.3

Sc

46.4

34.4

37.8

30.3

29.5

24.0

46.3

F /F + M

0.533

0.653

0.608

0.698

0.447

0.367

0.629

R b /S r

0.067

0.039

0.031

0.067

0.149

0.126

0.032

K /R b

469

703

598

790

329

252

1747

26.6

24.6

18.5

0 .0

0 .0

85.8

K /B a

2 2 .6

170

Hemlock Volcanics

KR-2

KR-3

KR-4

KR-5

KR- 6

KR-7

KR- 8

Ni

11.5

24.5

15.6

118.7

13.1

16.1

9.9

Cu

46.9

136.9

41.5

4.1

51.8

32.1

1.5

Zn

1 1 2 .1

85.7

127.9

99.5

131.8

84.8

82.6

Rb

36.9

13.1

1 0 .0

9.3

12.3

18.9

34.3

Sr

193.3

193.6

217.0

269.1

208.3

140.7

170.1

Y

29.8

19.5

27.4

16.1

27.1

30.4

61.5

Zr

164.3

84.5

175.7

81.0

171.4

182.9

563.3

Nb

19.6

7.9

20.7

1.5

2 1 .0

23.7

72.7

Ba

367.4

223.8

322.6

4145.4

249.5

260.7

903.9

La

27.85

12.82

24.33

10.43

28.13

29.09

187.97

Ce

57.13

28.88

56.99

18.29

56.61

64.45

275.17

Sm

5.98

3.39

5.64

2.76

6 .1 2

6.56

24.78

Eu

1.47

1 .1 0

1.58

1.36

1.73

1.63

5.28

Tb

0.92

0.55

1 .0 2

0.41

0.90

0.94

1.15

Yb

3.14

1.82

2.81

1.19

2.42

2.58

7.36

Lu

0.47

0.26

0.43

0.17

0.40

0.48

0.72

Hf

4.71

1 .6 6

4.48

3.44

4.96

5.16

15.13

Th

8.03

3.27

8.18

0.84

7.97

8.77

46.84

Cr

11.7

5.1

15.6

347.5

14.8

16.0

6.4

Sc

36.3

40.7

38.0

32.4

36.3

43.0

19.1

F /F + M

0.779

0.676

0.766

0.566

0.753

0.765

0.747

R b /S r

0.191

0.068

0.046

0.035

0.059

0.134

0 .2 0 2

K /R b

297

570

465

991

351

483

687

K /B a

29.6

33.4

14.4

17.3

35.0

26.1

Sample

2 .2

171

Hemlock Volcanics

Sample

KR-11

KR-12

KR-13

KR-14

LM-1

LM-2

LM-3

Ni

61.0

41.7

28.3

56.4

36.1

99.1

3.3

Cu

38.1

104.2

135.8

45.3

31.0

13.8

5.9

Zn

8 8 .0

85.5

104.2

78.3

127.3

86.3

97.1

Rb

5.9

4.0

11.5

3.9

7.5

14.9

14.6

150.5

109.8

137.1

75.9

233.2

637.0

16.6

36.4

18.4

27.8

Sr

2 2 1 .2

Y

17.6

16.9

Zr

8 8 .8

80.7

102.9

83.9

248.4

87.5

234.6

2 0 .8

6 .2

5.1

2 0 .1

Nb

8.5

9.5

14.1

10.4

Ba

97.9

178.8

272.8

118.6

330.2

669.0

279.7

La

10.45

12.69

14.41

9.81

40.11

11.57

43.20

Ce

30.68

26.04

31.58

22.87

106.28

22.16

72.94

Sm

3.19

2 .8 8

3.16

2.51

9.22

3.03

7.35

Eu

0 .8 6

0.90

0.81

0.81

2.69

1.09

2.84

Tb

0.69

0.45

0.73

0.43

0.89

0.45

0.95

Yb

1.96

2.29

2.48

1.95

2.75

1.15

2.52

Lu

0.36

0.39

0.40

0.32

0.41

0.24

0.48

Hf

2.29

1.84

2.85

2.28

10.63

2.38

5.25

Th

3.79

3.55

5.56

3.32

9.91

1.72

7.89

Cr

53.0

59.3

37.8

53.1

109.0

362.0

13.9

Sc

43.3

38.8

33.9

41.0

32.3

32.4

36.3

F /F + M

0.615

0.588

0.580

0.578

0.719

0.618

0.840

R b /S r

0.027

0.027

0.105

0.028

0.099

0.064

0.023

K /R b

689

872

6 8 6

1213

819

663

443

K /B a

41.5

19.5

28.9

39.9

18.6

14.8

23.1

172

Hemlock Volcanics

Sample

LM-4

LM-5

LM - 6

LM-7

LM - 8

LM-9

LM-10

Ni

203.3

35.1

41.6

41.6

35.7

71.2

54.6

Cu

49.3

107.4

72.1

114.6

183.3

82.4

75.5

Zn

82.3

111.3

101.9

115.7

121.9

93.9

105.7

Rb

6.9

14.6

2 1 .2

8.7

16.3

17.0

11.5

Sr

368.3

260.8

231.4

250.9

51.0

449.0

323.7

Y

13.4

27.3

28.1

27.3

27.7

24.9

23.8

Zr

78.8

161.3

163.0

169.9

158.8

149.2

139.9

Nb

3.3

13.4

15.0

15.0

20.9

15.1

12.4

Ba

116.2

387.1

634.2

377.1

350.3

478.5

440.2

La

8.16

20.42

19.08

21.30

17.22

17.83

15.12

Ce

19.38

50.20

52.30

49.23

47.31

43.73

39.38

Sm

2.41

5.45

5.69

5.23

5.34

5.06

4.46

Eu

0.89

1.57

1.72

1 .6 6

1.80

1.52

1.36

Tb

0.32

0.85

0.74

0.77

0.87

0.69

0.76

Yb

1.30

2 .6 8

2.97

2.43

2.79

2.39

2.29

Lu

0.17

0.43

0.42

0.42

0.43

0.38

0.39

Hf

1.62

4.03

4.30

3.87

4.20

3.37

3.32

Th

1.38

4.40

4.45

4.62

6.04

3.51

3.71

Cr

238.9

68.5

75.6

71.7

50.8

123.8

20.7

Sc

15.8

39.8

41.3

40.7

38.5

37.3

33.9

F /F + M

0.533

0.724

0.732

0.715

0.667

0.678

0.682

R b /S r

0.019

0.056

0.092

0.035

0.320

0.038

0.036

K /R b

565

586

556

630

1492

596

715

K /B a

33.6

18.6

14.5

69.4

2 2 .1

173

2 1 .2

18.7

Hemlock Volcanics

LM-14

LM-15

4.4

94.5

46.6

97.5

144.9

55.6

1 .8

122.3

122.7

7.4

130.2

59.6

99.5

74.2

68.4

7.2

38.4

14.0

32.0

6 .1

0.4

362.1

56.1

260.2

197.2

920.2

317.1

292.2

Y

23.5

28.4

40.8

20.4

23.0

13.5

14.2

Zr

137.4

169.5

313.7

142.7

127.3

64.1

79.1

Nb

9.1

2 1 .2

22.7

16.9

1 .0

2 .0

4.4

Ba

397.7

95.2

839.5

535.5

464.6

133.4

La

17.61

35.47

47.62

15.61

2 0 .0 0

6.28

13.81

Ce

51.31

46.75

104.14

36.50

52.67

17.41

21.50

Sm

5.36

6.04

12.40

4.56

2.95

2.13

2.67

Eu

2.28

2.13

2.95

2 .1 1

1.79

0.85

1.52

Tb

0 .6 8

0.55

0.81

0.64

0.77

0.28

0.40

Yb

2.26

2 .1 1

2.61

2.14

2.46

0.93

1.15

Lu

0.36

0.32

0.39

0.33

0.40

0.15

0.18

Hf

5.75

4.05

11.74

5.08

5.74

1.54

1.47

Th

3.65

3.25

8.08

2.80

4.49

0.38

1.67

Cr

107.4

93.5

90.5

235.3

195.7

469.6

64.9

Sc

z,u. 1

32.3

16.2

25.9

52.9

35.5

16.3

F /F + M

0.681

0.647

0.853

0.596

0.658

0.551

0.557

R b /S r

0.033

0.128

0.148

0.071

0.035

0.019

0 .0 0 1

K /R b

563

2409

452

753

280

667

K /B a

16.7

182.2

20.7

19.7

19.3

30.5

Sample

LM-11

LM-12A LM-13

Ni

69.6

56.3

Cu

44.4

118.7

Zn

107.4

Rb

1 1 .8

Sr

2 0 0 .2

174

LM-16

LM-17

0 .0

3528
0 .0

Hemlock Volcanics

Sample

LM-18

LM-19A

LM-19B

LM-20

KJ-1

KJ-2

KJ-3

Ni

218.4

146.7

138.7

34.1

46.4

22.3

78.3

Cu

98.9

119.3

34.8

38.8

21.3

4.0

8 8 .2

Zn

81.8

87.4

89.8

118.5

67.8

131.1

77.5

Rb

3.8

0 .0

1 .1

58.3

48.3

65.1

1 1 .8

Sr

99.0

95.6

98.5

133.7

75.8

108.1

148.1

Y

15.7

17.5

18.6

34.0

65.5

42.8

17.8

Zr

48.4

53.8

55.5

164.9

520.9

230.2

59.3

Nb

3.9

10.7

7.8

18.1

35.1

19.7

7.8

Ba

0 .0

9.7

23.7

867.9

1192.9

1446.8

593.9

La

10.70

5.45

4.00

15.01

113.53

41.17

10.04

Ce

19.69

24.52

24.96

29.45

174.57

78.71

19.89

Sm

1.60

2.40

1 .0 0

5.60

18.36

7.90

2.64

Eu

1.09

1.50

1.40

2.28

3.38

2.25

0.95

Tb

0.64

0.76

0.78

0.71

0.97

0.83

0.61

Yb

2.17

2.34

2.47

2.37

8.08

3.45

1.87

Lu

0.36

0.40

0.42

0.38

0.82

0.46

0.34

Hf

2.78

4.87

5.62

6.78

14.68

6.69

1 .6 6

Th

1.84

3.73

3.94

5.83

22.71

11.75

1 .0 2

Cr

265.8

297.6

310.8

112.5

75.7

16.9

274.8

Sc

38.0

39.9

39.9

27.5

26.2

36.4

42.7

F /F + M

0.540

0.580

0.589

0.680

0.794

0.813

0.594

R b /S r

0.038

0 .0 0 0

0 .0 1 1

0.436

0.637

0.602

0.080

K /R b

415

463

591

K /B a

0 .0

0

981

363

667

128.4

45.5

24.4

27.0

175

2 0 .8

11.7

Hemlock Volcanics

Sam ple

KJ-4

KJ-5

K J- 6

KJ - 8

Ni

148.1

38.0

176.4

6.9

Cu

49.2

6.5

37.4

47.5

Zn

77.9

106.8

1 2 1 .1

264.1

Rb

14.0

82.7

0 .6

15.9

Sr

248.0

505.0

58.4

449.1

Y

18.0

32.5

17.8

32.4

Zr

79.9

216.4

124.7

186.2

Nb

4.9

27.1

25.0

8 .6

Ba

141.9

1493.7

6 8 .6

939.4

La

20.81

61.51

8.34

33.72

Ce

2.52

6.87

28.19

62.59

Sm

1.09

2 .1 1

4.51

8.07

Eu

1.09

2 .1 1

1.51

2.53

Tb

0.41

0.69

0.61

0.85

Yb

2.03

2.24

1.70

2.72

Lu

0.32

0.37

0.31

0.46

Hf

1.91

5.47

3.13

4.44

Th

1.64

3.48

0.83

4.09

Cr

181.1

62.4

490.9

13.3

Sc

31.8

31.4

33.8

40.4

F /F + M

0.563

0.691

0.559

0.793

R b /S r

0.056

0.164

0 .0 1 0

0.035

K /R b

362

384

1660

621

K /B a

35.7

.. 21.3

14.5

10.5

176

M ona Schist

Sam ple

MQ-5

MQ- 6

MQ-7

NS-2

NG-1

Ni

164.4

223.5

92.6

161.2

160.7

Cu

1 1 0 .6

49.2

79.7

69.5

67.3

Zn

83.7

89.8

80.4

93.1

85.8

Rb

10.4

3.6

19.7

23.8

6.4

Sr

159.6

57.9

183.5

85.1

114.5

Y

18.4

17.6

22.5

2 0 .6

19.1

Zr

57.4

62.6

113.0

56.0

54.5

Nb

2 .6

6 .0

10.5

3.5

4.1

Ba

58.1

49.2

307.6

185.5

28.0

La

4.08

7.43

20.93

4.14

7.68

Ce

13.85

13.87

25.49

22.78

24.04

Sm

2.57

2.42

5.19

2.69

3.61

Eu

0.95

0.67

1.93

1.29

1.56

Tb

0.58

0.42

0.64

0.74

0.77

Yb

2.04

2 .1 1

2 .2 0

2.39

2.54

Lu

0.39

0.33

0.38

0.38

0.39

Hf

1.63

1.63

4.14

4.42

5.57

Th

0.49

0.25

3.94

3.88

4.77

Cr

251.0

464.9

165.7

270.6

291.4

Sc

40.3

37.0

29.4

33.3

39.0

F /F + M

0.611

0.580

0.645

0.635

0.593

R b /S r

0.065

0.062

0.107

0.280

0.056

K /R b

335

991

356

293

402

K /B a

60.0

72.5

22.9

37.6

91.9

177

Granite

Sample

CP-1

WL-3

KR-15

SQ-1D

W F- 6 C

Ni

7.9

0 .0

1.3

0 .0

0 .0

Cu

14.6

92.4

4.9

0 .8

1.9

Zn

71.7

70.7

89.2

14.0

38.1

Rb

94.2

86.4

74.3

132.1

65.5

Sr

228.7

58.7

57.9

64.4

502.6

Y

2 1 .2

44.0

52.4

30.5

18.3

Zr

123.4

303.2

418.1

37.3

176.1

Nb

5.0

23.4

57.1

9.3

0 .0

Ba

581.7

994.0

712.1

246.0

919.3

La

50.11

45.12

108.17

7.15

29.30

Ce

60.41

86.28

178.99

2.52

26.61

Sm

5.09

9.77

14.27

0.77

4.89

Eu

0.34

1.60

2.35

0.18

0.62

Tb

0.36

0.40

1 .0 1

0.19

0 .1 0

Yb

0.76

0.40

5.13

0.48

0.80

Lu

0.14

0.24

0.58

0.08

0 .1 1

Hf

12.05

3.29

10.97

0.81

1.94

Th

6.52

0 .1 0

35.23

3.95

0 .1 0

Cr

5.3

11.4

3.6

18.1

0 .1

Sc

27.6

9.7

10.4

0.3

16.9

F /F + M

0.661

0.892

0.851

1 .0 0 0

0.798

R b /S r

0.412

1.472

1.283

2.051

0.130

K /R b

278

413

469

392

442

K /B a

44.9

35.9

49.0

210.5

31.5

178

A PPE N D IX 3: Sam ple locations and map.

SYMBOL
★
■
•

DIKE
HEMLOCK
BADWATER

* MARQUETTE
' IRON
iWOOD

**

gogebi c

*

**

IR O N

MARQ

RIVER

CKINSON

SAMPLE
LOCATIONS

APPENDIX 3.
SA M PLE LOCATIONS

Dikes
FO-1: 350’ E, 400' N from SW corner, sec. 24, T43N, R33W , Fortune Lake
Quadrangle.
MR-1: 3200' S, 200' E from NW corner, sec. 30, T46N, R41W , Thayer Q uadrangle.
MR-2: 3200' due south of N E com er on section line sec.32, T46N, R41W.
GR-1: 1900' E, 50’ S from NW corner, sec. 22, T47N, R28W.
GR-2: 2850' E, 1600' S from NW corner, sec. 28, T47N, R28W.
GR-3: 1450' E, 2750' S from NW corner, sec. 28, T47N, R28W.
a: 20 cm from SW contact with granitic gneiss,
b: 7 m from SW contact.
GR-4: 1050' due east from west of sec. 5 / sec. 8, T47N, R28W.
MG-1: 500' E, 500" S from NW corner, sec. 22, T48N, R31W, M ichigamme
Q uadrangle.
MG-2: 2850' N, 450' E from SW corner, sec. 23, T48N, R31W.
MG-3: 1300’ E, 1850' N from SW corner, sec. 20, T48N, R30W.
NRP-1: 800' W, 2300' N from SE corner, sec. 1, T46N, R30W, R epublic Q uadrangle.
NRP-2: 1500' W, 400' N from SE corner, sec. 1, T46N, R30W.
NRP-3: 1850' W, 1900' N from SE corner, sec. 12, T46N, R30W.
NRP-5: 330’ south from JC T of SW R epublic/ M-95.
IP-1: 850' N, 150' W from SE corner, sec. 4, T47N, R27W, Ishpem ing Q uadrangle.
IP-2: 650' N, 1700' E from SW corner, sec. 10, T47N, R27W.
IP-3: 1050' N, 1050'E from SW corner, sec. 10, T47N, R27W.
IP-4: 500’ W, 500' S from N E corner, sec. 28, T47N, R27W.
IP-5: 1200' S, 1850' E from NW corner, sec. 28, T47N, R27W.
IP-6: 1050' W, 2500’ S from N E corner, sec. 16, T47N, R27W.
180

WL-1: 1500’ S, 2300’ W from N E corner, sec. 30, T47N, R30W, W itch Lake
Q uadrangle.
WL-2: 100' S, 2100' W from N E com er, sec. 30, T47N, R30W.
WL-3: 2200' S, 100' W from N E corner, sec. 24, T47N, R30W.
WL-4: 1100' W, 1000' S from NW com er, sec. 28, T45N, R31W.
MQ-1: 1800' W, 1300' S from N E corner, sec. 5, T48N, R25W, M arquette
Q uadrangle.
MQ-4: 1350' W, 500' S from N E corner, sec. 19, T48N, R25W.
RQ-1: 2900' S, 700' W from N E corner, sec. 1, T46N, R30W , R epublic Q uadrangle.
RQ-2: 4800' S, 1500' W from N E com er, sec. 1, T46N, R30W.
SQ-1: 2600' W, 1500' S from N E com er, sec. 18, T46N, R25W , Sand Q uadrangle,
a: contact south wall,
b: 1 m from south wall,
c: 7 m from south wall,
d: Com peau C reek Gneiss, north side.
SQ-2: 1500’ S, 2550’ W from N E com er, sec. 7, T47N, R25W.
a: at contact with Ajibik Q uartzite.
b: 15' from contact.
SQ-3: 1850' E, 1800' S from NW corner, sec. 7, T47N, R25W.
a: 1 or 2 m from SW contact,
b: 4 m from SW contact.
NSW-1: 100' E, 1200' S from NW com er, sec. 2, T47N, R27W, N egaunee SW
Q uadrangle.
NS-1: 1000' E, 800' S from NW corner, sec. 5, T48N, R26W.
RP-1: 450' W, 2200' N from SE corner, sec. 3, T47N, R29W, R epublic Q uadrangle.
RP-2: 1600' W, 750’ S from N E com er, sec. 21, T47N, R29W.
a: 7 m from SW contact of granitic gneiss,
b: 1.5 m from N E contact,
c: 20 cm from N E contact.
RP-3: 350' S from north of sec. 31/32, T47N, R29W.
RP-4: 1900’ E, 1000' N from SW corner, sec. 29, T47N, R29W.
RP-5: 600' E, 1300' N from SW corner, sec. 21, T47N, R29W.
WF-1: 2450'E, 250' S from NW corner, sec. 24, T47N, R45W, W akefield
Q uadrangle.

181

WF-2: 500' E, 1000' N from SW comer, sec. 12, T47N, R45W.
WF-3: 250' E, 700' N from SW corner, sec. 8, T47N, R45W.
WF-4: 2100' E, 650' S from N W corner, sec. 20, T47N, R45W.
WF-5: 2700' E, 1250' S from N W com er, sec. 20, T47N, R45W.
WF-6: 100' W, 500' S from N E com er, sec. 5, T46N, R45W.
a: chilled m argin at contact with granitic gneiss,
b: coarse grain,
c: granitic gneiss.
WF-7: 400' W, 3250' S from N E corner, sec. 8, T46N, R45W.

Badw ater G reenstones
CF-1: 2600’ E, 1350' N from SW corner, sec. 17, T43N, R32W, Crystal Falls
Q uadrangle.
CF-2: 2800' E, 1850' N from SW com er, T43N, R32W.
CF-3: 2500' W, 600' S from N E com er, sec. 20, T43N, R32W.
CF-4: 2350' W, 200' S from N E com er, sec. 20, T43N, R32W.
CF-5: 2500’ W, 300' N from SE corner, sec. 17, T43N, R32W.
CF-6: 1200' E, 250' N from SW corner, sec. 17, T43N, R32W.
FLE-2: 250' E, 1750' S from NW corner, sec. 14, T40N, R18E, Florence East
Q uadrangle.
FLE-3: 360' W, 750' S from N E corner, sec. 15, T40N, R18E.
FLE-4: 900' W, 900' S from N E corner, sec. 15, T40N, R18E.
FLE-5: 2000’ W, 500’ N from SE corner, sec.22, T40N, R18E.
FLE-6: 1500' W, 1400' N from SW corner, sec. 18, T40N, R19E.
FLE-7A: 100' N, 1100' E from SW corner, sec. 20, T40N, R19E.
FLE-7B: 30' east from FLE-7A.
FLE-8: 2400' W, 100' N from SE corner, sec. 20, T40N, R19E.
FLE-9: 1060' W, 750' N from SE corner, sec. 4, T39N, R19E.
FLW-1: 1700' E, 1200' S from NW corner, sec. 16, T40N, R18E, Florence W est
Q uadrangle.
182

FLW-2: 2700' N, 3250' W from SE corner, sec. 15, T40, R18E.
FLW-3: 2500' E, 2800' S from NW corner, sec. 9, T41N, R32W.
IM-1: 2100' E, 450' N from SW corner, sec. 2, T39N, R19E, Iron M ountain
Q uadrangle.
IM-2: 2400' W, 1250' S from N E com er, sec. 12, T39N, R31W.
IM-3A: 850' W, 1750' N from SE corner, sec. 11, T39N, R19E.
b: 10 m east from A.
c: 20 m east from A.
IM-4: 200' W, 1900' N from SE corner, sec. 11, T39N, R19E.
IM-5: 2200' E, 1500' S from N E com er, sec. 18, T40N, R31W.
IM-6: 350' north from south of sec. 9 / sec. 8, T40N, R31W.
IM-7: 2000' north from south o f sec. 12/ sec. 7, T40N, R31W.
IM-8: 3700' north from south of sec. 10/ sec. 11, T38N, R19E.
IM-9: 1000' north from south o f sec. 10/ sec. 11, T38N, R19E.

H em lock Volcanics
KR-1: 2450' north from south o f sec. 3 1 / sec. 32, T44N, R31W, K iernan Q uadrangle.
KR-2: 800' E, 1750' S from NW corner, sec. 5, T43N, R31W.
KR-3: 2200’ W, 900' N from SE corner, sec. 5, T43N, R31W.
KR-4: 2400' W, 650' S from N E corner, sec. 6, T43N, R31W.
KR-5: 800' W, 900' S from N E corner, sec. 6, T43N, R31W.
KR-6: 350' W, 1200' S from N E corner, sec. 6, T43N, R31W.
KR-7: 900' E, 1200' S from NW corner, sec. 5, T43N, R31W.
KR-8: 500' W, 1700' N from SE corner, sec. 4, T43N, R31W.
KR-9: 750' W, 850' S from N E corner, sec. 18, T43N, R31W.
KR-10: 1400' E, 2000' N from SW corner, sec. 5, T43N, R31W.
KR-11: 900' E, 2500' N from SW corner, sec. 5, T43N, R31W.
KR-12: 350' E, 2200' N from SW com er, sec. 5, T43N, R31W.
183

KR-13: 100' W, 1300' N from SE corner, sec. 6, T43N, R31W.
KR-14: 950' E, 2150' S from N W corner, sec. 5, T43N, R31W.
LM-1: 350' W, 150' N from SE corner, sec. 24, T43N, R32W, Lake M ary
Q uadrangle.
LM-2: 2250' E, 1550' N from SW corner, sec. 19, T43N, R31W.
LM-3: 1650' E, 1800' N from SW corner, sec. 19, T43N, R31W.
LM-4: 1550' E, 1450' S from NW corner, sec. 19, T43N, R31W.
LM-5: 300' W, 2300' N from SE corner, sec. 19, T43N, R31W.
LM-6: 450' W, 2100' N from SE corner, sec. 19, T43N, R31W.
LM-7: 1000' W, 2500' N from SE corner, sec. 19, T43N, R31W.
LM-8: 800' E, 900' S from NW corner, sec. 20, T43N, R31W.
LM-9: 450' E, 750' S from NW corner, sec. 20, T43N, R31W.
LM-10: 150' E, 250' S from NW corner, sec. 20, T43N, R31W.
LM-11: 250' W, 100' S from N E corner, sec. 19, T43N, R31W.
LM-12: 450' E, 2300’ N from SW corner, sec. 17, T43N, R31W.
LM-13: 1750' E, 2000' N from SW corner, sec. 5, T43N, R31W.
LM-14: 2500' W, 1500' S from N E corner, sec. 20, T43N, R31W.
LM-15: 1750' W, 1500' S from N E corner, sec. 20, T43N, R31W.
LM-16: 200' E, 2000' N from SW corner, sec. 21, T43N, R31W.
LM-17: 1550' E, 1400' N from SW corner, sec. 21, T43N, R31W.
LM-18: 2800' north from south of sec. 2 7 / sec. 26, T43N, R31W.
LM-19: 300' W, 1800' N from SE corner, sec. 27, T43N, R31W.
a: 2 m from surface,
b: 10 m from surface.
LM-20: 1100’ W, 250' S from N E corner, sec. 36, T43N, R32W.
LM-21: 1000' E, 2200' S from NW corner, sec. 33, T43N, R31W.
KJ-1: 1450' W, 3500' S from N E corner, sec. 11, T43N, R32W, Kelso Junction
Quadrangle.
KJ-2: 500' W, 3750' S from N E corner, sec. 11, T43N, R32W.
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KJ-3: 2500' W, 700' N from SE corner, sec. 11, T43N, R32W.
KJ-4: 2550' W, 1350' S from N E corner, sec. 4, T43N, R32W .
KJ-5: 1500' W, 1750' S from N E corner, sec. 33, T44N, R32W.
KJ-6: 2300' E, 1250’ S from N W corner, sec. 29, T44N, R32W.
KJ-7: 950' due east of N W corner on sec on line sec. 19/ 30, T44N, R32W.
KJ-8: coarse grain, sam e location as KJ-7.

M ona Schist
MQ-5: 2300’ W, 1000’ S from N E corner, sec. 19, T48N, R25W, M arquette
Q uadrangle.
MQ-6: 250' E, 2200’ N from SW corner, sec. 19, T48N, R25W.
MQ-7: 1500' E, 1100' N from SE corner, sec. 23, T48N, R25W.
NS-2: 1500' W, 1800' N from SE corner, sec. 5, T48N, R26W , Neganee Southwest
Q uadrangle.
NG-1: 300' E, 100' S from NW corner, sec. 26, T48N, R26W, N eganee Quadrangle.

G ranite
CP-1: 1350' N, 1650' W from SE corner, sec. 24, T48N, R29W, Cham pion
Q uadrangle.
WL-3: 100' W, 2200' S from N E corner, sec. 28, T45N, R31W , Witch Lake
Q uadrangle.
KR-15: 1750 E, 2000' N from SW corner, sec. 5, T43N, R31W, Kiernan Quadrangle.
SQ-1D: 2600' W, 1500' S from N E corner, sec. 18, T46N, R25W, Sand Quadrangle.
WF-6C: 2700' E, 1250' S from NW corner, sec. 20, T47N, R45W, W akefield
Q uadrangle.

185