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THE STRATEGRAPHY OF THE AU TRAEN

'FQRMA?§ON AT AU TRAIN FALLS AND

WAGNER FALLE, ALGER CGUNTY
ROWE-{RN MECHZGAN

thsts. §cr fine Degree of M. S.
MECHIGM‘E S?z§'§‘33 3L3 IE‘ERSHY
Daniel ‘33. Blake
1962

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31293 01071 7‘} 54

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L I B R A R Y
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TO AVOID FINES return on or beforo data duo.

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ABSTRACT

TRR STRATIGRAPHY OF THE AU TRAIN FORMATION
AT AU TRAIN FALLS AND WAGNER FALLS, ALGER
COUNTY, NORTHERN MICHIGAN

by Daniel B. Blake

The Au Train Formation of Northern Michigan occurs at the surface
near the shore of Lake Superior. It displays an east-west trend in
the eastern part of the peninsula. Southeast of Marquette, the out-
crop changes to a southwestward trend. There are relatively few
good exposures because of an overburden of glacial drift. The forma-
tion has been correlated with the Hermansville Formation by some
workers but because of the lack of field evidence this correlation
has been questioned. A distinct difference in lithology does exist
between the typical Au Train lithology and the typical Hermansville
lithology. This difference is responsible in part for the disagreement
in correlation.

Field work was done during the summer of 1961. A detailed
study was made of the rocks cropping out at Au Train Falls and
Wagner Falls. Other smaller outcrops were visited. Rock samples,
and, where possible, fossils, were collected for laboratory study.

In the laboratory, sedimentary analyses, including heavy mineral

study, was performed on selected specimens. This work suggested to the

Daniel B. Blake

writer that the An Train Formation was deposited in relatively quiet
water at shallow depth possibly under slightly reducing conditions
and under the partial influence of longshore currents.

The writer identified specimens of Lingulepsis exigga

 

(Matthew). To the writer’s knowledge, this is the first reported
occurrence of this species in the Upper Mississippi River Valley
area.

If the Au Train Formation proves to be Ordovician in age,

than the species range should be extended.

THE STRATIGRAPHY OF THE AD TRAIN FORMATION
AT AU TRAIN FALLS AND WAGNER FALLS,

ALGER COUNTY, NORTHERN MICHIGAN

by

Daniel B. Blake

A THESIS
Submitted-to
Michigan State University

in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
Department of Geology

1962

ACKNWLEIBEMENTS

The writer wishes to thank Dr. C. E. Prouty, under
whose direction this problem.was undertaken. The
writer also wishes to thank Dr. J. E. Smith and Dr. J. w.
Trow, the other members of the guidance committee, for
their suggestions and criticisms. The writer acknowl-
edges the Michigan State Geological Survey for information
on the location of outcrops.

Gratitude is expressed to David Cummings, graduate
student in the department of Geology, for advice,

suggestions, and criticism.

ii

CENTENTS

ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . .

LIST
LIST

LIST

II.

III.

IV.

VIII.

OF TABLES Q 0 O O 0 O O O O 0 O O O 0 O 0
OF FIGURES O O 0 O O O 0 O O O O O 0 O O O 0
OP ”Pmmcgs O O O O O O O O O O O O O O O O
INTROWCTI ON e e e e e o e e e e 0 e e e o 0
Purpose and Scope
Previous‘work
Location
FIELD PROCEDURES . . . . . . . . . . . . . .
srRATI W O O O O O O O O O O O O O O O 0
General Description
An Train Formation
Comparison to a Core from the Escanaba
Au Train Paleontology
Hermansville Formation
SEDI WATI m 0 O O O O O O O O O O O O O 0
Laboratory Procedure
Provenance
Environment of Deposition
SUMMARY AND CONCLUSIONS . . . . . . . . . .
SUGGESTIONS FOR FUTURE WORK . . . . . . . .
RmmCEs O O O O 0 O O O O O O O O O O O O

APPEDIX O. O O O O O O O O O O O O O O O 0

iii

Area

Page
ii

iv

vi

17

25
27
28

31

LIST OF TABLES
Table Page

1. A Listing and Count of Heavy Minerals Found in
the 125 Micron Sieve Size Samples . . . . . . . . 18

2. A Complete Listing of Heavy Mineral Grains in the
Studied Samples . . . . . . . . . . . . . . . . . 31

3. Carbonate Percentages at Au Train Falls and
Wagner Falls . . . . . . . . . . . . . . . . . 44

Figure

LIST OF FIGURES

, Page
Location of Studied Areas in.northern Michigan. . . 4

Location of Outcrops Displaying Dominant
Lithologic‘ O O O O O O O 0 O O O O O O O O O O 1‘

Generalized Geologic Columnar Sections of the Au
Train Formation at Au Train Falls and Wagner Falls,
Northern Michigan . . . . . . . . . . . . . . . . . 15

Correlation of Cambrian and Ordovician Formations . 16

APPENDIX
Page

Table 3-- A complete Listing of‘fleavy Mineral Grains
in the Studied Samples . . . . . . . . . . . . . . . . . 31

Mineral Descriptions . . . . . . . . . . . . . . . . . . 37
Light Minerals . . . . . . . . . . . . . . . . . . . . . 38
Histograms of the Au Train Formation . . . . . . . . . . 39

Description of Histograms . . . . . . . . . . . . . . . . 42

Section Descriptions . . . . . . . . . . . . . . .. . . 46

vi

INTRODUCTION

Purpose and Scope

The purpose of this thesis is a stratigraphic study of the An
Train Formation. An attempt is made to determine the formation's
environment of deposition and geologic age. The formation is in
Northern Michigan; the study is concentrated on the sections at Au
Train Falls and Wagner Falls.

Stratigraphic sections at Au Train Falls and Wagner Falls were
studied and samples were collected. Sedimentary analyses including
heavy mineral identifications were made. Paleontological studies were

made where possible. Fossil significance is noted.

Previous Work

Because of limited exposures, considerable disagreement has
existed as to the age and correlation of this formation. Reminger
(1873) suggested that these rocks were equivalent to the ”chasy” and
”calciferous' units of lew'York. After working in the Menominee'area,
Van Rise and Bailey (1900) applied the name'nermansville to the units
described by Rominger. Van‘nise and Bailey did not describe a distinct
type locality. Because of this shortcoming, Grabau (1906), after studying
the comparatively good exposures at Au Train Falls, proposed the term
“Aux Trains.” Bergquist (1937) retained the term "Bermansville" but
later authors have preferred the term "Au Train”, a slight modification
of Grabau's proposal.

-1-

-2-

Location
The area is located in the Northern Peninsula of Michigan. It is
in the north central portion of the peninsula along the south shore of

Lake Superior, near the town of Munising (Fig. 1).

FI ELD PROCEDURES

R. C. Russey and B. O. Ulrich in the summer of 1927 and R. C.
Russey in the summer of 1928 studied outcrops of Lower PaleosOic
rocks in Northern Michigan. The Michigan State Geological Survey
possesses information on the locations of these outcrops. The
survey permitted the writer to use this information. Many of the
lussey-Ulrich outcrops were small roadcuts which have apparently been
overgrown with vegetation since Russey's and Ulrich's field work.
Nevertheless, these outcrops were visited and studied where possible. '3
In addition, the writer looked for new exposures.

A sample or samples were collected at various locations.
Lithology was observed and location relationships between typical
Nermansville lithology and typical Au Train lithology were noted.
Attempts were made to find paleontological evidence.

However, the major portion of the writer's effort was expended
in the study of the sections at An Train Falls and Wagner Falls. These
two sections were measured in detail. Rand sample sized specimens were
collected at every major lithic variation. If no variation was noted,

random samples were collected at intervals not exceeding five feet.

-3-

 

 

 

 

FIGURE 1

LOCATION OF STUDIED AREAS
IN NORTHERN MICHIGAN

LAKE
SU P E RIOR
(LL29 AOI 5.0- 53.0400

. c) F
LAKE-
, MICHIGAN ’
SCALE IN MILES fl AI.

~LCCATICN OF AU TRAIN FALLS
AND. WAGNER FALLS

LAKE
SUPERIOR

 

    
 
  

  
  
 
    
 

NORTHERN
' MICHIGAN

WISCONSIN

 

 

 

 

 

 

 

  
 

USFS 2278

'I AU TRAIN LAKE

AU TRAIN FALLS —=—
0 M9

MUNSING

O I 2 3
4 SCALE IN MILES

 

 

 

 

 

   

 

STRATIGRAPHY

General Section

The rocks considered herein are underlain by the Munising Sand-
stone which has been correlated with the Dresbach and Franconia
formations of Wisconsin on the basis of heavy minerals (Driscoll,
1956). 3

The Au Train and Rermansville lithologies rest on the
Munising sandstone. The Au Train and Nermansville are considered to
be a facies relationship by some workers (Ramblin, 1958). Other 3
workers (Prouty, personal communication) consider the two units to be
stratigraphically distinct in time because of a difference in lithology
which exists between the‘Rermansville as described at Menominee and
the rocks at Au Train Falls. Ne (Prouty) further compares the
lermansville lithology to the Prairie du Chien of Wisconsin and the
Southern Michigan subsurface: and the Au Train to the typical Upper
Cambrian Sandstones of Wisconsin. The Hermansville consists of a
relatively pure dolomite whereas the Au Train at Au Train Falls is a
dolomitic sandstone which contains abundant pyrite and glauconite.
Ramblin (1958) believes a facies relation exists between the two
lithologies. Oetking (1951). after studying the Hermansville-type
lithology at the town of Eben, between Au Train Falls and Menominee,
concluded that these rocks are twenty feet stratigraphically above the

'top of the exposed section at Au Train Falls. The writer knows of no

-5-

-6-

location where the contact between the typical Hermansville lithology
and typical Au Train lithology can be observed. Therefore the relation-
ship eanmot be as yet conclusively determined.

On the basis of fossils, Oetking and Namblin believe the Au
Train to be lower Middle Ordovician (Black River). This interpretation
has been questioned because of the poor quality of the preservation of
the Au Train fossils which renders conclusive identification difficult
(Prouty, personal communication).

The rocks overlying the Au Train Formation have been classified
as Middle Ordovician (Cohee, 1948). These rocks are commonly fossil-
iferous. At the van Meer quarry east of MMnising the writer collected

and identified specimens of the following forms.

Cephalopods

Actinoceras beloitense (Whitefield)
Endoceras proteiforme (Ball)
Murryoceras murrayi (Footste)

 

 

 

 

Gastropod

Raphistoma sp.
Pelecypod

Vanuxemia sardesoni (Ulrich)
Brachiopod

Strophomena incurvata (Sheppard)

 

Au Train Formation

The Au Train Formation forms the cap rock of an escarpment of
Munising Sandstone along Lake Superior. In Alger County, west of
Mhnising. this escarpment has receded from the lake shore. In this

county many waterfalls are developed on the Au Train Formation and a

-7-

considerable thickness of this unit may be exposed.

The best exposures known to the writer are at Au Train Falls and
Wagner Falls, the two sections considered in this study.

The carbonate-elastic percentages (Table 3, appendix) show that
the formation, in general, ranges from a dolomitic sandstone to a
quartaose dolomite in its exposed thickness. however, the elastic
content is locally variable.

Oetking (1951) believed the Munising-Au Train contact at Au Train
Falls to be located slightly below the lowest of the series of falls.
On the basis of heavy minerals, Driscoll (1956) suggested that this
lowest portion of the falls is formed by the MMnising Sandstone. On
the basis of gross lithology, the writer concurs with Driscoll. The
writer believes the first Au Train rock to be the four inch band of
glauconite lecated at the top of the lower falls.

At Wagner Falls, the base of the Au Train Formation crops out at
the top of a step-face well above the foot of the falls. The rock
contains abundant glauconite and also pebbles of the friable coarse
grained'Munising Sandstone implying that the latter formation was
=partially reworked. I

When fresh, the Au Train is light grey to light brown with
glauconite commonly imparting a greenish hue. The rock weathers to a
darker yellow brown. 3

In the lower portion of the formation the bedding is thin and
irregular with numerous shale lenses. Glauconite is abundant in
disseminated form as well as in concentrated bands which are up to
several inches thick. Bands of concentrated quartz sand are common.

Pyrite is present, being visible in the hand specimen. Cross bedding

and ripple marks occur.

In the stratigraphically higher, more dolomitic portions of the
exposed section, the bedding is more massive. Glauconite is less
important than in the lower portion of the fornntion. Quartz sand
bands are common. Pyrite is apparent at many horizons forming nodules
up to one inch long. Fossils, while extremely rare, are present.
Because of the local variation in lithology, the writer was unable to
make a detailed correlation between the two sections.

Hamblin (1958), from investigations of well cores, reports the
Au Train Formation to be 300 feet thick. Only the lower portion of
this thickness crops out at Au Train Falls. Good exposures of the
upper portion of the formation have not been found.

Ramblin (1958) reported that a covered interval fifteen feet
thick occurs at Au Train Falls. Because of subsequent erosion along
the stream bank, the writer believes this thickness of rock is now
“exposed. At‘Wagner Falls, however, many thin covered intervals
occur.

The measured sections of the Au.Train Formation measured by the

writer at Au Train Falls and Wagner Falls may be seen in Fig. 3.

Comparison to a Core
from the Escanaba Area

R. A. Dixon (1961) studied a well core from Delta County
northwest of Escanaba, Northern Michigan. The writer compared his
glithology to those lithologies reported by Dixon. The author record-
ed a some of prominent pyrite, glauconite and garnet. This zone rests
on a sandstone which contains well rounded sometimes frosted quartz.
An increase in garnet is reported to occur higher in the section.
Dixon considers this to be equivalent to the Dresbach and Franconia
units of Wisconsin. It would therefore be comparable to the
Munising Sandstone of the Lake Superior shore. Hence the overlying
sons rich in pyrite, glauconite and garnet may be equivalent to the
Au Train Formation of the lake shore because of the similar lith-
ology and minerals. Dixon considers this zone of his well core to be
Trempealeau in age. He bases this correlation on the lithologic
shmilarity to the Trempealeau of Wisconsin. Because of Oetking's
(1951) fauna, the writer considers the An Train to be Middle
Ordovician in age. There are two possible explanations for the
conflict in time designations between Dixon and the writer.

1. The units, in spite of lithologic and
stratigraphic continuity, may not be
correlatives.

2. The lithologic correlation to Wisconsin
may not be valid.

Dixon’s study includes rocks designated as Middle Ordovician in

age. The unit he considers to be Black River in age is rich in pyrite.

-9-

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-10-

but is relativily pure dolomite, quartz and garnet being minor.
Glauconite is not reported. Beneath this zone is a sandstone which
contains abundant garnet and, in addition, some pyrite and glauconite.
Dixon considers this zone to be the Glenwood equivalent.

The writer feels he does not possess sufficient information to

formulate a valid correlation between the two areas.

Am Train Paleontology

The fossil content of the Au Train Formation is limited.
Oetking (1951) and Bamblin (1958) collected in a road cut near
Miners Castle. The writer, in an attempt to find new forms, concentrat-
ed his effort on other areas.

A new outcrop was found on a country road 1 1/3 miles due east
of an outcrop described by Bussey in his field notes (see Fig. 2).
The outcrop is in the form of a shallow drainage ditch along the north
side of the road. The ditch was dug in the spring of 1961 exposing
about eight feet of the Au Train Formation section. The material fran
the ditch was placed along the ditch'e bank. Several fragments contain-
ing fossils were found in the trenched material about one vertical
foot from the top of the outcrop. The freshness of the specimens that
contain the fossils and the location of the three samples together
in trenched material, all of the same lithology, has convinced the
writer that the samples were derived from this location. However,
the writer stresses that ultimately it cannot be proven that the
samples were derived from bedrock at this location.

One of the three samples collected at this site contains only

fragments impossible to identify. The other two samples contain

-11-

brachiopods. One brachiopod specimen is the exterior of a ventral
valve and the other is the interior of a dorsal valve. Both were
identified as Lingulepsis exiggg (Matthews) by the writer. A shell
fragment, believed to be of the same species was found in place at

Au Train Falls. To the writer's knowledge, this species has not been
described beyond the Cape Breton area. It also has been restricted
to the Upper Cambrian. If the Au Train Formation is Black River,
then the range of the species should be extended.

Another possibility concerning these specimens would be that
they were reworked from an Upper Cambrian formation. If this were
the case, then its stratigraphic range might be the same as at Cape
Breton.

Lingulepsis exigua (Matthew).

Ventral exterior: length 10 mm., width 8 mm..
acuminate, very fine radiating straie, concentric
growth lines forms a minutely irregular granulose
surface at the anterior portion of the shell.
Dorsal interior: anterior portion missing, frag-
ment length 5 mm., width 7 mm., triangular outline:

the vascular system left a central double groove

with a slight ridge in between, lateral grooves

are also present; rows of pits along the concen-

tric growth lines partially obscure the vascular grooves.

In addition to the forms mentioned above, the writer found two
inarticulate brachiopods and a low spired gastropod, none of which
could be identified.

The writer also found several small short cylindrical pyrite
aggregates. It is suggested, on the basis of shape, that these are
organic in origin, perhaps from worm burrows. The pyrite is presumed
to have replaced the original organic material.

The University of Wisconsin permitted the writer to study

Oetking's fauna. Oetking’s fauna, as reported by him in his study,is

-12-

listed below.

Cystoidea

Pleurocystites cf. 3, sqamosus (Billings)

Brachiopoda

Linggla sp.

Gastropoda

Sinuites sp.

Sinuites sp.

Bucanella cf. 2,.nana (Meek)
Pterotheca cf. P. e ansa (Emmons)
Raphistomina cft’g. lapicida (Salter)
Raphistoma sp.

Trochonema sp.

Liospira cf. L. micula (Ball)
Eotomaria suprecingulata (Billings)
Clathrospira subconia (Hall)
Belicotoma planulata (Selter)
Archinacella sp.

 

 

 

 

 

Scaphopoda
Bzolithes cf. E, baconi (Whitfield)
Prescochiton cf. canadensis (Billings)
Cephalopoda

Endoceras

Trilobita

Basiliella barrandi_ (Hall)

 

The writer concurs with Oetking's designation of the fauna as

Middle Ordovician.

-13..

Bermansville Formation

 

Because the relationship between the Au Train lithology and
the Barmansville lithology has not yet been fully established, the
Bermansville is here considered separately.

The area in which the Bermansville occurs is a low drift-cover-
ed plain stretching southwestward from about the town of Eben. The
occurrence farthest to the southwest is near Iron Mountain, Michigan.
No good outcrop sections are known to the writer. Bussey (1936)
described the rocks at Trenary as being somewhat siliceous
argillaceous limestone. He reports irregular bedding varying from
one inch to one foot. Oetking describes the rock at the town of
Eben as a ”fine-grained yellowish-grey dolomite evenly but sparsely
scattered with frosted quartz grains.“

Few fossils have been found. Raminger (1873) reported
molluscan shell fragments. Van Rise and Bailey found further material,
”a broken orthoceras, a fragment resembling a piece of cyrtoceras, a
gastropod, and several other fragmentary forms..."

I

LOCATION OF OUTCROPS
DISPLAYING DOMINANT LITHOLOGIES

LAKE
SUPERIOR

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o TYPICAL HERMANSVILLE LITHOLOGY
e LOCATION OF OUTCROP WITH LEXIQLJA

HGURE;2

-14-

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SYSTEM

MICHIGAN

BASIN

 

SERIES

SOUTHERN PENINSULA

MUNISING AREA

 

 

ORDOVICIAN

TRENTON
BLACK RIVER
GLENWOOD

TRENTON
AU TRAIN

 

 

MOHAWK

ST. PETER

 

SHAKOPEE

 

NEW RICHMOND

 

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FIGURE 4

CORRELATION OF CAMBRIAN AND ORDOVICIAN FORMATIONS

(AFTER COHEE,DIXON ,DRISCOLL,AND OETKING)

SEDIMENTATION

Laboratory Procedure

 

In the laboratory, the samples were crushed between boards.
The samples were then weighed and placed in a 1:4 solution of
hydrochloric acid where they remained until the carbonate fraction
was dissolved. The acid was then siphoned. The sample was washed
in water, filtered, dried and weighed. For the Wagner Falls section,
every fourth field sample was run for heavy mineral analysis. For
the Au Train Falls section, however, difficulty was encountered in
adhering to this method. Therefore the intervals of selection are
slightly irregular.‘ The samples were sifted through D. S. standard
sieves with openings of 710, 500, 350, 177, and 125 microns. The
amount retained in each sieve size was weighed. The heavy minerals
of the 125, 177, and 250 sieve sizes were separated in bromoform. The
separations were restricted to this size range because the grain
samples larger than 250 contain a paucity of heavy minerals. The size
of the grains under 125 microns render them difficult to identify,
hence they were also deleted. Some of the heavy mineral grains were
placed in a mounting medium of index N a 1.67. They were identified
and counted. The unmounted heavy mineral grains were studied with a
binocular microscope. Table 2 (appendix) lists completely the mineral
identifications and descriptions. Table l (p. 18) lists the results
of the identifications and counts from the 125 sieve size in a more

consice form. —

-17-

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-19-

Provenance

 

The heavy minerals imply that an ultimate source rock could
have been a schist on the Shield. However, many of the heavy minerals
display a high degree of rounding. This would suggest that the
grains were either reworked or were subjected to a large amount of
weathering and rounding prior to deposition. Driscoll (1956), on the.
basis of size, rounding and heavy mineral content thought the An Train
Formation to be either partially or wholly derived from the underlying
Munising Sandstone. The writer found muscovite and gold in the Au
Train Formation, neither of which have been reported from the
Munising Sandstone. ‘Hence, in addition to the Munising Sandstone, the

writer suggests that another source rock is required.

Environment of Deposition

Glauconite is the most striking feature of the Au Train Formation
occurring in concentrated bands up to four inches thick. It may be
locally absent, but, in general, it occurs in disseminated form through-
out the thickness of the exposed section. Glauconite is commonly dull
green and ovaloid in shape.

Pyrite is also very common, although it is usually not obvious
in the hand specimen. Nodules up to one inch in length occur at some
horizons. Microscopic crystals (cubes and octahedra) commonly retain
excellent crystal form. Some of the cubes are striated. Pyrite is
commonly imbedded in glauconite. Several pyrite aggregates, short
and cylindrical in shape were observed. It is suggested that these'
represent worm burrows. Because of the euhedral form of the pyrite,

its occurence imbedded in glauconite and its occurrence as worm

~20-

burrows, it may be at least in part authigenic. Driscoll (1956)
reports pyrite in the Munising Sandstone, which is considered, at
least in part, to be the Au'rrain Formation source rock. Also,

pyrite veins occur in the Au Train Formation. Hence part of the
pyrite was introduced following the rock's deposition. The glauconite
may also be in part authigenic. The morphological features of the
glauconite as listed above has beanrcited as evidence for authigenic
origin of this mineral (Light, 1952).

The above observations would imply certain conditions of deposi-
tion. Cloud (1955) lists physical limits of glauconite formation,
some of which are summarized below as it would apply to the sections
studied by the writer.

1. The present areal distribution of glauconite

deposition is mainly on continental shelves

away from large streams.

2. As far as is known, glauconite originates
only in marine waters of normal salinity.

5. Its formation requires slightly reducing
conditions.

4. Glauconite formation may be cyclic.
5. The depth of formation is usually neritic.

6. Temperature tolerance is wide, although
formation is not favored by water of
excessive warmth.

7. The water may be somewhat turbulent.

8. The source material may be micacous minerals
or bottom.muds of high organic content.

9. Sedimentary influx is probably slight, preferably
only enough to supply the needed elements. By-
passing of the very fine fraction could accomplish
the same result as minor sedimentary influx.

-21-

There is another possible explanation for the origin of the
glauconite and pyrite; this is an epigenetic one. The weakness of
the proposed syngenetic origin is related to the oxygen content of the
water. The Au Train Formation appears to be of shallow water origin.
This is suggested by the intraformational conglomerates which imply
that the bottom was at least occasionally above wave base. The pres—
ence of coarse sand grains implies proximity to the shore. The fauna,
although limited, is sufficient to suggest a relatively shallow
environment.

The turbulence, the streams, and the hypothesized longshore
currents (see below) could all serve to introduce oxygen to the
environment no matter how restricted the environment. In order to
maintain reducing conditions, a greater amount of organic material
is necessary than might reasonably be expected. The glauconite and
pyrite could therefore have been formed slightly beneath the
depositional interface under reducing conditions away from the influence
of oxygenated waters. IA reducing environment is considered necessary
for glauconite formation. This requirement is absent above the
depositional interface.

Pyrite is an important constituent of the muscovite-rich suite,
but glauconite is minor or absent. Carrels (1960) states that
glauconite and pyrite form in a similar pH range but that pyrite
forms under conditions of lower oxidation potential. This would
suggest that the currents in some manner reduced the oxidation
potential.

The above argument is based on the theory that at least slightly

reducing conditions are required for glauconite formation.

-22-

Teodorovich (1961) states ”The mineral is the product of a special
marine mineralogical-geochemica1 facies, namely the glauconite facies,
characterized by repeated microfluctuations in the oxidation-reduction
boundary, i.e. characterized by repeated microfluctuations in the
oxidation-reduction boundary, (sic) i.e. characterized by a struggle
between oxidizing and reducing conditions, oxidizing conditions
generally dominating." He cites several Russian publications to
support his hypothesis. Teodorovich mentions other factors believed
necessary for glauconite formation. He states the mineral is formed
in the shelf zone along a there of magmatic rocks away from river
mouths in areas of strong bottom currents where sedimentation is
retarded or ”reversed.” Transgressions and regressions leading to
movements of marine waters which in turn disturbs the equilibrium
favors glauconite formation. Because of the presence of glauconite
in carbonates, the temperature of formation cannot have been too low.
He further states that optimum.temperatures and depth of glauconite
formation has not been consistent throughout geologic time but that
”they (the conditions) have depended on the salinity ofthe marine
waters, on the mineralization, and on other factors.” Teodorovich
does, however, believe that glauconite may be of diagenetic origin.
The writer does not feel qualified to draw conclusions concern-
ing the conditions under which the Au Train glauconite was formed.
Table l (p.18) reveals a division in the occurrence of heavy
minerals. The Au Train Falls section more clearly displays this
division. Muscovite occurs either as the predominant non-authegenic
heavy mineral or as a minor-to-absent constituent. Where muscovite

is minor or absent, garnet is the predominant mineral. Thus two

-23- '

suites are discernable, a muscovite suite and a garnet suite. If the
heavy minerals were derived solely from the Munising Formation, then
no muscovite should be present, for muscovite has not been reported
in this rock by previous authors. Therefore, another source rock is
required.

If it were assumed that streams entering the area of deposition
contained all the heavy minerals, then, because of differential ,
settling rates, muscovite should not be found in significant quantities‘
associated with other heavy minerals.

The muscovite occurs in relatively large quantities and is
rounded and largely unaltered. Krynine (1940) states that, "Rounding
of the micas indicates a specialized set of sluggishly moving currents
with a gentle to-and-fro motion." It is therefore suggested that the
mmscovite was introduced by longshore currents independent of the other
heavy minerals. If these conditons did exist, then these currents
would carry relatively minor amounts of coarse material and relatively
large amounts of fine material. Therefore sediments deposited under
the'influence of these currents should contain a high percentage of
fine material and a relatively minor percentage of coarse material.

Histograms of weight percentages were prepared (appendix, Table
3). The histograms are also discussed in the appendix. I

At An Train Falls, over 80% by weight of the muscovite rich
Imamples is found to be less than 125 microns in size. In those
samples in which garnet is dominant, the percent of fines ranges
from about 15% to 50%..

The section at Wagner Falls does not display as uniform a

division as does the section at Au Train Falls. Two samples (R7-10,

n25-

R7-50) also contain relatively large quantites of quartz in the coarser
sieve sizes.

Another possible cause for the combined suite exists. As a
result of the highly interbedded nature of the formation, some of the
individual samples studied consisted of a comparatively coarse quartz
sand glauconitic rock in contact with a fine grained clay rich
relatively quartz free rock. The writer believes the garnet may occur
in the quartz rich glauconitic layer while muscovite occurs in the

finer grained layers.

SUMARY AN D QWCLUSI Q18

The Au Train Formation of Northern Michigan, as it appears in
outcrop at Au Train Falls and Wagner Falls, is primarily a dolomitic
mandatone. The rock is rich in glauconite which occurs disseminated
as well as in concentrated bands. Hearly pure quartz bands are also
present. Pyrite is common. The lower portion of the formation is
more highly glauconitic and contains more quartz than is in the
upper portion.

Much of the pyrite and glauconite may be authigenic. This
suggests that the formation was deposited in relatively shallow quiet
water under slightly reducing conditions. It is also possible that

the glauconite and pyrite were formed penicontemporaneous below the
depositional interface. On the basis of heavy minerals and the
appearance of the quartz grains, previous authors have suggested that the
source rock for the Au Train Formation consists in part or in whole of
the underlying Munising Sandstone. The presence of gold and muscovite,
not previously reported, suggests to the writer that another source
rock is necessary. Where muscovite occurs, there is, in general, a
paucity of other minerals. Because of this the writer suggests that
longshore currents were present which introduced muscovite independent
of the other minerals.

Fossils are rare in the Au Train Formation. Previous authors
have found material which leads them to believe the formation to be
Black River. This age has been questioned by some workers. The

-25-

 

-26-

writer found a specimen of Lingulepsis exiggg (Matthew) which has not,

 

to the writer's knowledge, previously been reported outside of the
Cape Breton area. In addition it has not been reported to range beyond
the Upper Cambrian. The geographic range of this species must be
extended. Its temporal range may also need to be extended.

The writer was permitted to study P. E. Oetking's fauna. The
writer believes the fauna to be Middle Ordovician. Hence, the Au
Train Formation would also be of this age. This would imply a facies
relationship between the Au Train - Black River rocks and the relatively
pure carbonate Black River units found elsewhere in the area. The
writer considers the term.Ae Train to be valid if restricted to the
quartzitic glauconitic rock as it occurs at A: Train Falls. Ho study
*wes made of the Hermansville lithology nor of the relationship be-

tween the Hermansville and Au Train Formation.r

SUGGESTIONS FOR FUTURE WORK

More information on the environment of deposition and the
possibility of the influence of longshore currents may be gained by
a more detailed lithologic study of the Au Train Formation at Au
Train Falls and Wagner Falls. In addition, other outcrops should be
studied to determine local variation of heavy mineral content. The
relationship between Hermansville lithology and Au Train lithology
has not yet been determined .‘di...d. further work.

More detailed paleontological work remains to be done. The
promising new outcrop described by the writer should be further

investigated.

-27..

REFERENCES

BERGQUIST, S. G., 1929, The occurrence of Glauconite in the
Hermansville formation of Alger County, Michigan: Paper
Mich. Acad. Sci. Arts and Letters, v. 12.

, 1956, The Cambrian-Ozarkion contact in Alger County,
Michigan: Paper Mich. Acad. Sci. Arts and Letters, v. 22.

CLOUD, P. E. JR., 1955, Physical limitations of Glauconite Formation:
Bul. AAPG, v. 39, no. 4.

GUESS, G. F., 1948, Cambrian and Ordovician rocks in Michigan and
joining areas: Am. Assoc. Petrol. Gaol. Bull., v. 52, no. 8.

DIXON, H. A., 1961, Lithologic study of a Cambro-Ordovician core,
Delta County, Michigan: Unpub. thesis, Mich. St. Univ.

DRISCOLL, E, G., 1956, An environmental and heavy mineral study of the
”eastern sandstones” between Marquette and Grand Marais, Michigan:
Unpub. Thesis, Univ; Neb.

DRISCOLL, B. G.. 1959, Evidence of transgressive-regressive Cambrian
sandstone bordering Lake Superior: Journal of Sedimentary
Petrology, v. 29, no. 1, p. 5-15. .

FOERSTB, A. F., 1924, Notes on American Paleozoic cephlopods; Denison
Univ. Bull., Jonrn. of Sci. Lab., v. 20.

, 1932, Black River and other cephalopods fromIMinnesota,
Wisconsin, Michigan and Ontario; pts. I and II, Denison Univ.
Bu11., Journ. of Sci. Lab., vol. 27. -

FOERSTB, A. F. and TEICHERT, C., 1930, The actinoceroids of east
central North America; Denison Univ. Bull., Jour. of Sci. Lab.,
vol. 25.

GARRELS, 1961, Mineral equilibra: New‘York, Harper Brothers.

GRABAU, A. W., 1906, Types of Sedimentary overlap; Bull. Geol. Soc.
Am., v. 17. '

HALL, J., 1897, An introduction to the study of the genera of

Paleozoic brachiopods, Pt. I: Gaol. Survey of the State of
NewITork, Paleontology, v..8., Albany, N. Y.

-28-

-29-

HAMBLIN, W. K., 1958, The Cambrian sandstones of Northern Michigan:
Mich. Geol. Surv. Pub. 51.

HELLER, R. L., 1956, Status of the Prairie du Chien problem; G.S.A.
Guidebook Ser. Field Trip lo. 2, p. 29-40.

HOWELL, B. F., 1944, Correlation of the Cambrian formations of Berth
America: G.S.A. Bull. v. 55.

UUSSY, R. C., 1936, The Trenton and Black River rocks of Michigan:
Mich. Geol. Surv., Pub. 40.

Index ot‘Miehigan Geology, 1823-1955; Mich. Geol. Surv., Pub. 50.

KAI, G. M., 1935, Ordovician system in the upper Mississippi valley:
Kan. Geol. Soc., 9th Am. Field Cont. Guidebook.

KRUMBINB, W. C. and SLOSS, L. L., 1958, Stratigraphy and sedimentation:
w. B. Freeman and Co., San Francisco.

KRYBINE, P. D., 1940, Petrology and genesis of the third Bradford
sand: Penn. St. College Bull. 29.

LABBB, F. B., 1952, Field geology: Bew‘York, McGraudflill Company.

LIGHT, M. A., 1952, Evidence of anthigenic and detrital glauconite:
Science, v. 115, no. 2977.

HEIRER, B. B., 1940, Sedimentary petrology: 3rd ed., London, Murby.

OETKIBG, P. F., 1951, The relation of the lower Paleozoics to the
older rocks in the northern peninsula of Michigan: Unpublished
Ph. D. Thesis, Univ. of His.

PITTIJOEB, F. J., 1957, Sedimentary rocks: New York, Harper and
Brothers.

RAASCH, G. 0., 1935, Stratigraphy of the Cambrian system of the
upper Mississippi valley: Kan. Geol. Soc. 9th Am. Field Conf.
Guidebook.

ROGERS, A. F. and KERR, P. F., 1942, Optical mineralogy: Rev'York,
McGrawdflill Book Co.

ROMIIGBR, C. L., 1873, Paleozoic rocks: Mich. Geol. Surv., v. 1. pt.
111.

SBIMER, B. W. and SRROCK, R. R., 1944, Index fossils of lorth America:
new York, John Wiley and Sons.

TEODOROVICB, G. 1., 1961, Authigenic minerals in sedimentary rocks:
translated from the Russian by Consultants Bureau, New York,
1961. . '

 

{r-

 

 

TEWAITES, F. T., 1912, Sandstones of the Wisconsin coast of Lake
Superior: Wis. Gaol. Nat. Hist. Surv. Bull. 25.

, 1934, wells in the northern peninsula of Michigan showing the
Cambrian section: ‘Mich. Acad. Sci. Arts and Letters, papers,
v. 19.

, 1943, Stratigraphic work in.lorthern'Michigan: Mich. Acad.
Sci. Arts and Letters, papers, v. 28.

TRASK, P. D., ed., 1955, Recent marine sediments: reprinted by the
Society of Economic Paleontologists and Mineralogists Special
Publication No. 4, Tulsa, Oklahoma.

ULRICH, E. 0., et al., 1897, Geological and natural history survey of
Minnesota: v. 3, pt. 11.

ULRICH, E. 0. and COOPER, G. A., 1938, Ozarkian and Canadian
brachiopods: Geol. Soc. Am. Special Paper No. 13.

van RISE, c. a. and BAILEY, w. s., 19oo,‘u.s. Geol. Survey Geol. Atlas,
Menominee Folio, lo. 62.

WERMUND, E. G., 1961, Glauconite in early Tertiary sediments of gulf
coastal province: Bull. Amer. Assoc. Petrol. Geo1., v. 45,
No. 10. “ .

WHITFIELD, a. P., Geology of Wisconsin: v. 1v, Pt. 111.

WIIMARTH, M. G., 1938, lexicon of geologic names of the United States:
U.S.G.S. Bull. 896.

APPENDIX

TABLE 2

A COMPLETE LISTING OF HEAVY MINERAL GRAINS
IN THE STUDIED SAMPLES

A2_Train Falls
Number of Grains

 

 

Sample Number in Sample

3502— 250*

pyrite, occurs with glauconite 125
R5C2- 177

pyrite, occurs with glauconite 106
R502- 125

pyrite, occurs with glauconite 203

garnet 1

ilmenite observed in unmounted
heavy traction

R5C9- 250
pyrite, occurs with glauconite 50
leucexene 1
R5C9- 177
pyrite, occurs with glauconite 51
leucomene 5
RSC9- 125
pyrite on glauconite 117
leucoxene 6
garnet 11
'tourmaline 4

ilmenite l

 

*Sieve sise in microns

-31..

TABLE 2- Continued

Sample lumber

RSCI? - 250
Pyrite, glauconite rare

R5C17- 177
pyrite, glauconite rare
garnet

R5Cl7- 125
pyrite, little glauconite
garnet
tourmaline
leucoxene
hornblende
ilmenite observed in unmounted sands

R5C34- 250
pyrite, no glauconite

RSC34- I77

R5C34- 125
pyrite, no glauconite
leucoxene
muscovite
ilmenite, garnet and gold, all rare,
occur in unmounted sands

R5D3- 250
pyrite, no glauconite

3503- 177

pyrite, no glauconite
muscovite

RSDS— 125

pyrite, no glauconite (assoc. w. qtz.)
muscovite

RSDIO- 250

RSDIO- 177

pyrite, no glauconite
muscovite

RSDIO- 125

pyrite, glauconite rare
muscovite
leucoxene

Number of Grains
in Sample

29

61
l

85
27

188
44

44
11

-33-

TABLE 2L- Continued

Number of Grains

 

 

Sample Number in Sample
R5D18- 230
pyrite, with glauconite 3
leucoxene 1
R5D18- 177
pyrite, with glauconite 10
muscovite 4
leueoxene 2
R5D18- 125
pyrite, with glauconite 27
garnet 53
leucoxene 4
tourmaline l
muscovite 2

ilmenite occurs in unmounted grains

R5D22- 250
pyrite with glauconite 16
R5D2Z- 177
pyrite with glauconite 58
garnet 3
leucomene 1
R5022- 125
pyrite with glauconite 49
garnet 87
tourmaline 3
hornblende 1
muscovite l

ilmenite in unmounted grains

R5D31- 250
pyrite in glauconite 28
R5D31- 177
pyrite with glauconite 67
garnet 1
RSD3l- 125
pyrite with glauconite 111
garnet 47
tourmaline 1
leucoxene 2

ilmenite l

-34..

Wagner Falls

' Number of Grains
Sample lumber in Sample

 

 

R7-2- 250

pyrite with glauconite 10
R7-2- 177

pyrite with glauconite 45

muscovite 2
R7-2- 125

pyrite, with glauconite 85

muscovite ll

garnet 11

hornblende 1

leucoxene ' 3

ilmenite 3
R7-6- 250

pyrite and glauconite 2
R7-6- 177

pyrite and glauconite 18
R7-6- 125

pyrite with glauconite 33

muscovite 23

garnet 8

leueemene. 14

tourmaline 1

ilmenite in unmounted sands

R7-10- 250
pyrite minor, much glauconite - 18
27-10- 177 ,
pyrite minor, much glauconite 55
hornblende 1
leucoxene l
R7-10- 125
pyrite minor, principally glauconite 8
garnet 177
leucoxene 5
horneblende ’ l
R7-14- 250

pyrite minor, principally glauconite 27

-35-

TABLE 2-.Continued

Sample Number

R7-14- 177
Pyrite minor, principally gluconite
muscovite

37-14- 125
pyrite minor, principally glauconite
garnet
muscovite
hornblende
ilmenite in unmounted sands

R7-18- 250
pyrite with glauconite

R7-18- 177
pyrite with glauconite

R7-18- 125
pyrite with glauconite
garnet
leucoxene
tourmaline
muscovite

37-22.; 250
pyrite, glauconite absent

R7-22- 177
pyrite, glauconite absent

R7-22- 125
pyrite, glauconite absent
muscovite
ilmenite occurs in unmounted sands

R7-26- 250
pyrite, glauconite absent

R7-26- 177
pyrite, glauconite absent
muscovite

R7-26- 125
pyrite, glauconite absent
garnet
leucoxene
muscovite
ilmenite in unmounted sands

Number of Grains
in Sample

 

92
1

118
10

100

87
14
10

110

275

245
11

134
36

40

Sample Number

R7-30— 250

pyrite with glauconite
garnet

R7-30— 177
pyrite with glauconite
garnet
tourmaline

R7-30- 125
pyrite with some glauconite
garnet
tourmaline
gold
ilmenite
muscovite
leucoxene

Number of Grains
in Sample

12
8

HHHHb-l-‘sl

Pyrite

Glauconite

Almandine
garnet

Muscovite

Leucoxene

Tourmaline

Hornblende

Gold

Ilmenite

MINERAL DESCRIPTIONS

The dominant heavy mineral. Generally occurs as an
aggregate with either galuconite or quarts. Pyrite
is commonly surrounded by glauconite. It displays
excellent cubes and less commonly, octahedra.

The presence of glauconite in the heavy mineral
assemblages is explained primarily on the basis

of its association with pyrite. Teodorovich does
report glauconites maximum specific gravity as
being between 2.85 and 2.90 which is in excess of
the 2.86 specific gravity of bromoform. The
glauconite varies in color from pale to dark green.

. It is usually present as an aggregate. No good

optic figures were seen. Hardness about 2, indices
near to 1.61. Pyrite is commonly imbedded in it.

Isotropic red, index over 1.67. Grains vary from
well rounded to grains with good crystal faces.
Some grains with re-entrant angles. Proximity of
garnets index to the index of the mounting medium
imparts a distinct bluish tint to some grains. The
variation in roundness and the variation in indices
as indicated by the blue tint are both graduated,
hence differentiation of garnets is not possible.

Translucent colorless tabular crystals with vitreous
luster, minor alteration. Excellent cleavage flakes
yield excellent biaxial negative optic figures.

2V I 40°. Index under 1.67.

A pitted dull white opaque mineral, commonly on
ilmenite grains.

Well rounded brown pleochroic length fast uniaxial
negative grains.

Rounded and fractured green pleochroic unaltered
grains, oblique extinction, biaxial positive.

very thin, very soft metallic gold colored flakes.
Although uncommon in slides, it is found in un-
broken rocks.

Opaque dark submettalic rounded grains; partial
alteration to leucoxene common.

-37-

LIGHT MINERALS

Several slides of light minerals were prepared. The principal
constituent is well rounded quartz grains, frosted either by wind
action or solution. The second major constituent is feldspar,
identified by its biaxial negative interference figures and on the
basis of twinning. Measurements on combined-carlsbad twins places
the composition of one grain in the andesine plagioclase range. Good
crystal development is common. There is some alteration and
decompositon of the crystals. No secondary overgrowths were observed.
It is not known if the feldspar is derived from igneous or metamorphic
rocks or if it is authigenic: however, the presence of the andesine
suggests it is at least in part primary. The other principal lights
are glauconite and calcite, dissolved either partially or wholly in

the preparation of the material for study.

-38-

°/o

WEIGHT

FORMATION
AU TRAINFALLS
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-39-

  
   

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R503
R5010

R5018

R5022

R5031

R7-2
R7-6

R7-10

DESCRIPTION OF'HISTOGRAMS
Ap_Train Falls

No significant amount of heavy minerals. Samples largely
glauconite, some quartz.

Garnet suit, 177 sieve size forms about 35% of the sample,
fines (those grains under 125 microns) form under 20% of
the sample.

Garnet suite 177 sieve size forms about 35% of the sample,
fines are under 30%.

Because of similarity, these three muscovite-rich samples
are considered together. In all samples, the fines exceed
80%. The larger the sieve sizes, the smaller the weight
percentage. This was not true in previous samples.

Primarily garnet, although 2 of the 86 counted grains were
muscovite. Fines less important than in previous 3 samples
while the 177 and 125 sieve sizes both exceed 20%.
Primarily garnet, although 1 of the 147 counted grains was
muscovite. The 177 micron sieve size forms over 50% while
the fines form about 15%.

A garnet suite with no muscovite being observed. The

250 sieve size is the principal component, forming over
40% of the suite. Fines again form about 15%.

WAGNER FALLS
Combinations of both suites, in which the fines are

dominant.

A garnet dominant sample, the fines are under 10%,

R7-l4
R7-18
R7-26
R7-22

R7-30

-4 3..

Combinations, although fines are dominant.

Muscovite suite

Sample with quantities of garnet, muscovite very minor,
fines very minor.

TABLE 3

CARBONATE PERCENTAGES AT A0 TRAIN FALLS
AND‘WAGNER FALLS

Ap_Train Falls

% %' %
R58

1 78.5 25 14.8 10 - 57.1
2 55.0 26 54.1 11 58.8
27 79.8 12 59.2
250 28 33.5 13 38.7
2 71.2 29 25.2 14 30.8
3 50.5 30 75.7 15 67.3
4 47.5 31 65.3 16 43.4
5 35.1 32 27.6 18 33.4
6 35.6 33 75.8 19 48.5
7 38.6 34 50.8 20 42.8
8 40.2 35 70.2 21 67.6
9 27.1 36 27.4 22 59.6
10 24.3 37 33.1 23 46.2
11 26.6 38 51.8 24 53.9
12 41.0 25 61.9
13 38.6 R50 26 52.4
14 34.0 1 42.8 27 75.2
15 42.6 2 43.5 28 39.2
16 36.3 5 56.9 29 57.6
17 46.6 4 44.0 50 10.4
18 44.9 4 5.8 31 70.2
19 19.3 5 45.7 32 85.3
20 31.6 6 52.5 53 80.4
21 56.4 7 19.7 34 61.2
22 15.4 8 58.0 35 87.2
24 6.6 9 57.5 56 70.3
37 79.1

 

Note: The lowest exposed rock is RSB-l, the highest is
R5D37. Positions of selected samples may be seen
in Fig. 3.

-44-

-45-

TABLE 3—- Continued

Wagner Falls

% % %
R7 R7 R7
~ 1 55.6 ~13 45.4 ~24 67.9
~ 2 30.1 ~14 32.7 ~25 59.6
~ 3 29.8 ~15 27.7 ~26 52.4
~ 4 35.4 ~16 53.7 ~27 49.8
~ 5 27.0 ~17 38.4 ~28 43.5
~ 6 39.0 ~18 46.3 ~29 35.2
~ 8 59.8 ~19 38.7 ~30 52.2
- 9 41.0 ~20 14.9 ~31 40.0
~10 16.6 ~21 43.6 ~32 9.0
«111 75.2 ~22 47.1 ~33 24.8
~12 54.9 ~23 80.6

Unit

No.

SECTION DESCRIPTIONS

Ap_Train Falls

Unit

Thickness

Munising Sandstone

Bedding 1” to 4', coarse grained

rounded frosted grains, minor

glauconite, vugs, some gastropods,

some horizons conglomeratic 6'

Au Train Formation
Quartzose dolomite, quartz sand is

fine grained, disseminated glauconite
gives greenish gray color, clay blobs,

intraformational conglomerat3_ 4'

 

' w" ~M-w

 

Dolomitic sandstone interbedded with

layers of high glauconite content,
glauconite usually occurs disseminat-

ed, bedding under two inches, pyrite

present but minor, partially cross-

bedded 1'

Dolomitic sandstone containing
disseminated glauconite and clay
blobs, some pyrite, quartz, sand is
fine grained, cross-laminated,
glauconite bands under 1” thick,

'intraformational conglomerat 8§*

 

.—

 

 

Dolomitic sandstones similar to #4,
except laminae are more regular, fewer

' clay blebs are present, carbonate vugs,

local glauconite bands 8’

Principally quartzose dolomite with
dolomite being locally subordinate,
some clay blebs, local pyrite nodules
up to 2 inch in diameter,_some

Cumulative
Thickness

6.

65*

74c

16'

24'

Unit

No.

10

-47-

SECTION DESCRIPTIONS~~ Continued

Unit Cumulative
Thickness Thickness

 

intraformational conglomerates, gray

to brown color glauconite is subor-

dinate, bedding thicker than in

previous units ’ 10' 34'

Dolomitic sandstone, similar to #4,

irregular laminae, intraformatignal

conglomerate, locally friable sand

layers, local clay bleb concentrations,

generally fine quartz sand, conglom-

eratic glauconite layer occuri‘itT*

EESTEBpTofTEhis interval 14' 48'

Quartzose dolomite, contains a pyrite

rich horizon near the base of the

interval, veins and nodules up to 1'

long occur, local conglomerates and

carbonate vugs, glauconite is minor,

occurs disseminated 8' 56'

A sequence of rocks similar to #7 and
#8 with clestic and carbonate material
alternating as the dominant feature,
local pyrite, disseminated glauconite,
quartz sand is locally coarse, friable
quartz sand layers several inches thick

occur . _ 209 75.

The remainder of the section is a

quartz sand dolomite with the carbonate

percentage increasing upward in the

section, glauconite is locally absent,

but occurs disseminated in quantity at

local horizons, pyrite occurs locally,

local sand horizons, fresh rock is, in gen-

eral, gray, it weathers buff, the top of

the interval contains an intraformational

conglomerate 16' 92'

-48-

.‘c-

SECTION DESCRIPTIONS- Continued

Wagner Falls

 

 

 

 

Unit Unit Cumulative
No. Thickness Thickness
Buffy)“. ("NJ _A_u Train Formation
l Quartzose dolomite, glauconite,

conglgpgpgtic, pebbles of Munising-
type lithology up to two inches in
diameter, pebbles are partially

cemented by carbonate, quartz sand
is rounded and frosted, similar to

the Munising type sand 1' l'
2 Covered interval li' 2i'
3 Dolomitic sandstone, layers of material

rich in clay, glauconite rich bands
occur, alternate with bands of rounded
quartz sand, sand is finer grained than at

the contact, thin bedded 1" 1' 25'
4 Covered interval
5 Rock similar to #3 1' 6'
6 Covered interval ' 2' 8'
7 Dolomitic sandstone, thinly bedded,

contains clay blebs, color is light buff,

glauconite is scattered in the matrix,

numerous fine grained friable quartz sand

bands are present, glauconite is present

disseminated and in thin bands 108' 185'

8 Quartzose dolomite, glauconite and
quartz—rich bands alternate with clay-
rich bands, rock is more massive and
thicker bedded than in the lower
intervals, several distinct sand bonds
are present, the sand being coarser
grained in the bands than in the dolomitic
rock, cross bedded, pale buff color 9%' ' 28'

9 Covered interval 2' 30'

Unit

No.

10

11

12

13

-49-

sacnon nescmpnms_ Continued

Unit

Thickness

A largely covered interval, rock is,

in general, similar to the material
described under #3, dolomitic sand-

stone, clay blebs and glauconite

scattered irregularly throughout,

quartz sand is relatively fine grained 14'

Similar to #10 except no part of the
interval is covered, contains two

thin bedded friable glauconite rich

bands ’T_‘ 12'

Quartzose dolomite, gray in color,

variable quartz sand content, fine

grained, glauconite is sparsely

scattered throughout, pyrite occurs
disseminated and in vugs,some
intraformational conglomerate,

pebbles aggmflat, dolomitic 9'
Remainder of section quartzose

dolomite to dolomitic sandstone,

light buff clay blebs and pyrite is

present with the pyrite being common-

ly concentrated, glauconite is un-
important, bedding igmmorehmassive

than it is lower in thggsection,

contains bands of friable coarse

grained quartz sand 18'

Cumulative
Thickness

44'

56'

65'

83’

R0 I5 USE 0511'

I.-! 34' W '

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