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(a. ..J’;. - pt... \ 1 u A O.- . . ...A ..Icnw‘l....l...ro .. . . . a . . . . . .6.a...o. ll.v . . . - ... .. ... . ....... .c91~.;..i‘o...o..L.-\\4...I.£.9 . .. . . . .... . . .. . . o . .. .... ..4 ...t.. ._ .... .( . .AL . .. .. . .. . . .. . ......4... . .. . ... .... l ...... .....v. . ....L O ......1 .. . . .4 . . . o ..- ...‘oHOdfl‘ . . . c v I . o . . . u .\ . . I ’8. . . . . , . .. .,. . l . ..o . .. .u x... . ... *1. . .I o.....k..\L‘e.(.-— 5. KogabVL9k0 0;6 A .9 . ‘1 4 . . . . . . .4:- ._ ., ... - . .... :4. ..M'. . . . .. I .. ,0! ...... .o . ‘1 o 0.0... .40.... . .. ..4..; o .. .-..8.J. Co . ... 0| .\.1 .. 0.. .. c v A .1. . . . .4 ‘ >.....\ .r- .......4,.. no. Q.Ov.. ... .1..7 .. .. g . ‘u.fll.‘ . v.— I—sJuV. r” ‘ ‘111111111111111111111 E: ,, 31293 01109 9698 . . ...: Umversxty (’3‘ "I,— A9310 .2000 t ..1 15;:I ABSTRACT A STUDY OF SAMPLES FROM THE KNOWLTON AMYGDALOID, CALEDONIA MINE, QNTONAGON-COUBTY, MICHIGAN By Milton A. Gere, Jr. The study was made to try to determine the degree of homogeneity or heterogeneity in a vertically "homageneous" sample area by trying to identify patterns of igneous minerals, textures, structures, and metamorphic, hydro- thermal and oxidation characteristics from an edit, a one- level drift along a structural contour. The Knowlton amygdaloid ("lode") within the Caledonia mine, Ontonagon County, Michigan was the subject of the study. The Knowlton amygdaloid is part of the Portage Lake Lava Series which is a middle Keweenawan age series of 9,000 to 15,000 feet of altered basalt flows and inter-flow con- glomerates which have been mined for many years in the Michigan copper district. Thirty-one samples were collected over a length of 2900 feet of drift along a horizontal structural contour. Most of the samples were taken at 100 foot intervals, offset where needed due to local conditions. Ordinary, petrographic, and metallographic microscOpes were used to study thin and polished sections made from the samples. The polished sections were also used as hand samples for rough megascopic classification, and adjacent Milton A. Gere, Jr. slices of material were ground to a fine powder and used for rock color determinations. The percentages of individual minerals and mineral assemblages within the samples were tabulated and correlated with the amount of the same minerals or mineral assemblages in other samples. Cross correlations were made between associated minerals, etc., and the amount of the specimen consisting of amygdules, vesicles and veinlets. The grain sizes of plagioclase and pyroxene and the sizes of the amygdules, etc., were also studied. Observation of the correlation charts showed that twenty-nine of the thirty-one samples mostly appear to con- fine themselves to seven general groups, based upon mega- scopic appearance, which are somewhat similar in micro- scopic characteristics. Some of the groups are more well defined than the others. The similarities reoccur, but not in any orderly manner, giving no real pattern, but suggest- ing some type of repetition. Since the Knowlton amygdaloid is described as being a brecciated amygdaloid, at least in part, it is concluded that the seven sample groups are actually due to the flow being of a brecciated character in this location. In this manner all samples in one group could be from within a breccia block, another group could represent interstitial material, a third group may have been affected by adjacent joints, etc. A STUDY OF SAMPLES FROM THE KNOWLTON AMYGDALOID, CALEDONIA MINE, ONTONAGON COUNTY, MICHIGAN By Milton A. Gere, Jr. A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Geology 1970 TO MY MOTHER AND LATE FATHER 11 ACKNOWLEDGMENTS The writer wishes to express his thanks to the follow- ing for their assistance: Dr. J. W. Trow for his suggestions and guidance as chairman of the thesis committee. Dr. H. B. Stonehouse for his advice on the form of the final presentation of the data and serving on the thesis committee. White Pine COpper Company and Copper Range Company for allowing the author access to the Caledonia mine to collect the sample material while in their employ in 1966, and for supplying the thin sections. J. L. Patrick, of White Pine Copper Company, for initially suggesting the study and arranging for the company cooperation. R. J. Leone, of COpper Range Exploration Company, for his recommendations and assisting the author in collecting the sample material. Dr. Alan Bailey for his many helpful suggestions. 111 TABLE OF CONTENTS LIST OF TABLES. . . . . . . . . . . . . . . . . LIST OF FIGURES . . . . . . . . . . . . . . . . I INTENT OF STUDY . . . . . . . . . . . . . II INTRODUCTION. . . . . . . . . . . . . . . General Geology . . . . . . . Location. . . . . . . . . . . . . . . History of the Area and Mine. . . . . . Previous Work . . . . . . . . . . . . . III PBOCEDIJRE O O O O O O O O O O O O O O O 0 Collection of Samples and Sample Location Descriptions. . . . . . . Petrographic Microscope Work. Mineral Identification Bock Textures. . . . . Opaquese e e e e e e Modal Analyses . . . . Reflecting Microscope Work. X-ray Diffraction . . . . . Sample Color Comparison . . Hand Specimens. . . . . . . IV OBSERVATIONS AND CORRELATION OF DATA. Minerals Present and Percentages. . Minerals Present . . . . . . . Metallic Minerals Present. . . Mineral Percentage Correlations Anorthite Content . . . . . . . . . Rock Textures . . . . . . . . . . . GrainSizeeeeeeeeeee Amygdules, Vesicles and Fractur Bock Color. . . . . . . . . . . . . Hand SpecimenS. . . . . . . . . . . S eeCDeeeeeee V SAMPLE GROUP DESCRIPTIONS AND CORRELATIONS. iv Page vi Vii -q UHVDJH’ +4 14 VI VII VIII IX SUMMARY AND CONCLUSIONS . . . . . . RECOMMENDATIONS . . . . . . . . . . BIBLIOGRAPHY. . . . . . . . . . . . APPEND ICE 0 O O O O O O O O O O O O A com Individual Sample Descriptions Correlations . . . . . . . . Percentage Mineral Charts. . . Correlation Charts . . . . . . Miscellaneous Charts . . . . . Page 31 39 36 43 43 61 75 85 LIST OF TABLES Table Page 1 Minerals Present (in %) . . . . . . . . . . . . . . 14 vi LIST OF FIGURES Figure 1 Map of Michigan, locating Ontonagon County . . . 2 Map of Ontonagon County, locating Mass . . . . . 3 Map of Caledonia mine at Mass, Michigan . . . . h Photomicrograph - pumpellyite in amygdule (thin section, sample 10).. . . . . 5 Photomicrograph - amygdule with pumpellyite in quartz, some epidote (thin.section, sample 28) 6 Photomicrograph - amygdule with calcite, epidote and quartz (thin section, sample 10) . . . . 7 Photomicrograph - plagioclase and hematite about amygdule with epidote crystals in quartz (thin seetion, sample 29)e e e e e e e e e e 8 Photomicrograph - altered plagioclase and hematite (thin section, sample 28) . . . . . . 9 Photomicrograph - plagioclase and pyroxene (polarized light) (thin section, sample 20). . 10 Photomicrograph - rectangular hematite grains (mlished BeCt10n, Sample 7) e e e e e e e e e 11 Photomicrograph - hematite rims around minerals (polished section, sample 28) . . . . 12 Photomicrograph - hematite grains along rim of amygdule (polished section, sample 10) . . . . 13 Photomicrograph - hematite grain showing twinning (polished section, sample 1).. . 1h Photomicrograph - scattered native copper grains (polished section, sample 5). . . . . . 15 Photomicrograph - scattered native co per grains (polished section, samp1e2 2? . . . . 16 Photomicrograph - native copper in amygdule (polished section, sample 17).. . . . . . . . 17 Photomicrograph - native copper in veinlet (polished Section, sample 11)e e e e e e e e e 18 Percent plagioclase vs. sample number. . . . . . 19 Percent pyroxene vs. sample number . . . . . . . 20 Percent olivine vs. sample number. . . . . . . . 21 Percent leucoxene vs. sample number. . . . . . . 22 Percent iddingsite vs. sample number . . . . . . 23 Percent hematite vs. sample number . . . . . . . 2h Percent sericite-saussurite vs. sample number. . 25 Percent pumpellyite vs. sample number. . . . . . 26 Percent chlorite vs. sample number . . . . . . . 27 Percent epidote vs. sample number. . . . . . . . vii Page 13 13 13 Figure 28 29 30 31 32 33 3h 35 36 37 38 39 no 41 42 1&3 an as #6 47 #8 49 50 51 Percent calcite vs. sample number . . . . . . . Percent pyroxene and olivine vs. sample number. Percent hematite and iddingsite vs. sample number. . . . . . . . . . . . . . . . Percent sericite-saussurite and pumpellyite vs. sample number e e e e e e e e e e Percent sericite-saussurite, chlorite and pumpellyite vs. sample number . . . . . . . . Percent sericite-saussurite, chlorite, pumpellyite, calcite, and epidote vs. sample number . . . . . . . Percent p1agioclase,pumpellyite, sericite- saussurite and epidote (dashed line includes K- feldspar) vs. sample number . . . . . . . . Percent olivine, pyroxene, iddingsite, and chlorite vs. sample number. . . . . . . . Percent ratio of plagioclase, pumpellyite, sericite-saussurite and epidote (dashed line includes K-feldspar) to olivine, pyroxene, iddingsite and chlorite vs. sam 1e number . . Percent cOpper (visual estimation vs. sample n‘mber. O 0 O O O 0 O O O O O O O O O 0 Percent amygdules, vesicles, and veinlets vs. sample number . . . . . . . . . . . . . . . . Comparison of the mineral percentage vs. emple nllmber chartS. e e e e e e e e e e e e Comparison of percent plagioclase vs. percent sericite-saussurite and pumpellyite . . . . . Comparison of percent plagioclase vs. percent sericite-saussurite, chlorite and pumpellyite. Comparison of percent pyroxene vs. percent epidote and chlorite . . . . . . . . . . Comparison of percent pyroxene and olivine vs. percent plagioclase. . . . . . . . . Comparison of percent pyroxene and olivine vs. percent iddingsite and chlorite. . . . . . . Comparison of percent chlorite vs. percent hematite and iddingsite. . . . . . . . . . . Comparison of percent chlorite vs. percent olivine and pyroxene . . . . . . . . . . Comparison of percent chlorite vs. percent amygdules, vesicles and veinlets . . . . . . Comparison of percent amygdules, vesicles and veinlets vs. percent sericite-saussurite, chlorite-and pumpellyite . . . . . . . . . . Comparison of percent amygdules, vesicles and veinlets vs. percent sericite-saussurite, chlorite, pumpellyite, calcite and epidote . Percent anorthite vs. sample number . . . . . Size range of plagioclase grains vs. sample numbereeeeeeeeeeeeeeeeeee viii Page 66 66 66 68 68 68 7O 7O 72 72 74 76 80 80 81 81 82 82 83 83 84 8h 85 86 Figure Size range of pyroxene grains vs. sample nWbereeeeeeee eeeeeeeee Size range of amygdules and vesicles vs. sample number . . . . . . . . . Grouping of hand samples according to general color, texture, etc. vs. sample number. . Rock-color chart number vs. sample number GY color value plots. . . . . . . . . . . R color value plots . . . . . . . . . . . YR color value plots. . . . . . . . . . . ix Page 87 88 89 89 9o 92 INTENT OF STUDY The objective of the study was to try to identify patterns of igneous minerals, textures, structures, and meta- morphic, hydrothermal and oxidation characteristics from an edit, a one-level drift along a structural contour, to determine the degree of homogeneity or heterogeneity in a vertically "homogeneous" sample area. Any repeating hetero- geneity may indicate the amygdaloid had been a brecciated flow top. INTRODUCTION General Geology The Michigan native cOpper district lies mostly in the Portage Lake Lava Series which is a northeast trending, northwest dipping series of 9,000 to 15,000 feet of numerous altered basalt flows and inter-flow conglomerates of middle Keweenawan (Precambrian ) age. Many of the flows and con- glomerates may be recognized over a number of miles along strike by those very familiar with them. The copper is found primarily in the native state as amygdule fillings and fracture fillings in the basalts, and as inter-fragmental fillings in the conglomerates. To the south-southeast of the flows is the Keweenaw Fault which separates the Portage 1 2 Lake Lava Series from the Jacobsville sandstone of disputed age - either upper Keweenawan.or Cambrian. Many generalized accounts of the geology of the district can be found in the literature. a The Caledonia Mine is a drift along strike within the Knowlton amygdaloid which is a brecciated amygdaloidal flow top recognized over only a relatively short distance in the southern end of the district. The bedrock of the area dips from about no to 50 degrees to the northwest. Location The samples studied were collected from the Knowlton amygdaloid ('Knowlton lode") of the Portage Lake Lava Series within the Caledonia Mine, near Mass, Ontonagon County, Michigan. This is near the southern end of the ICapper Range" which extends from Copper Harbor in the NE to Victoria in the SW. The mine is an adit-drift running in a NE-SW direction, along strike, in parts of the NE quarter of section 12 and the SE quarter of section 1, range 39 W, township 50 N, and the SW quarter of section 6, range 38 w, township 50 N. The location is roughly 6700 to 7700 feet in a northwesterly direction from the Keweenaw Fault. History of the Area and the Mine Copper was known in the Michigan native copper district by Indians about 3000 B.C. (N. 5. white, 1968, p. 306). In 18hl Douglas Houghton published a report on the district. Mining started in 18hh and was carried on nearly continuously '72 Figure 1 Map of Michigan, locating Ontonagon County Mass and the Caledonia Mine Miles Figure 2 Ontonagon County, Michigan Mass mine Sec. 1 Sec. 6 Caledoni Mine Caledonia Adit Nr Sec. 12 I 1 0 1000 Feet Nebrask Adit Modified from 1966 White Pine COpper Co. modification of 1929 map from U.S.G.S. Professional Paper 1hh. Figure 3 Map of Caledonia mine at Mass, Michigan 5 within the district until 1969 when the last operator shut down. Many of the mines in the district were very small, changed ownership a number of times and went through several alternating periods of mining activity, being shut down, and leased out to tribute workers. Most of those that sur- vived consolidated into larger companies, with the Calumet and Hecla Company being the last Operator on the range until 1969. The Caledonia Mine was originally started as the Nebraska in 1855, became the Caledonia in 1863, and part of the Flint Steel COpper Co. in 1871. In 1873 the mines shut and were leased until 1881. The Caledonia is adjacent to and now connects with the Knowlton Mine and the larger Mass Mine which started in 1857 and ran most of the time into the 1920's. Eventually the Calumet and Hecla Company obtained the Caledonia Mine property and did some explora- tory work in the late 1950's, leaving some stopes full of un-mucked ore when they abandoned the property. In the early 1960's Copper Range Company became the owner after a property trade with Calumet and Hecla. The adit lay idle and was supposedly sealed shut in 1967-1968, with access reportedly now open only to trespassing rock-hounds and geology students. Previous Work Much has been written on the district as a general area. Butler and Burbank's U.S.G.S. Professional Paper 14“, is a 6 very large and complete publication which tries to tie to- gether all of the work done on the area up to that time. It includes the geology of the area, production records of the various mines, and a study of the ore deposits themselves. In 1929, T. M. Broderick wrote on the zoning of the deposits of the district. He based his work largely on the arsenic content of the copper minerals that are found in the mines in the northeastern end of the range. Broderick wrote on the vertical differentiation of some flows in 1935 and suggested that a horizontal study of a flow over a long distance be made to look for possible differ- ences along strike. (P. 557). H. R. Cornwall wrote three related papers in 1951 con- cerning the vertical differentiation of several flows which he compared to Broderick's earlier work. His work was an expansion of Broderick's, but favored a syngenetic - epi- genetic origin for the copper instead of a straight epigenetic origin. Stoiber and Davidson published a different theory of zoning of the deposits in their 1959 article. Their study showed that the mines are located in areas where there are epidote, quartz, and prehnite as over-lapping amygdule zones, and that copper was not found in large quantities where there was much quartz and/or prehnite. They also showed; 1) the zoning was not cenfined to particular beds but cut across stratigraphic horizons, and 2) the deposition 7 of the copper as well as the other amygdule fillings occurred after the tipping of the beds. No detailed geologic work has been published on the Caledonia Mine as such. The mine has been only mentioned in references to work on the whole district. PROCEDURE Collection of samples and sample location description Hand samples were collected from the wall on the side of the drift away from the stOpes along 2900 feet of drift. Samples were taken from approximately hi feet above the floor. The interval between samples was in most cases one hundred feet, at or near the station marks placed on the wall for some earlier mine engineering project. One sample, number eight, was taken at a shorter interval because of a noticeable change in the rock. Sample 31, station 0, was not painted in, and sample 9 was taken at about 2165 feet into the drift, offset because the station 2200 location was in a fallen rock area. Sampling could possibly have extended farther into the drift but the area appeared to enter some of the older workings and to be areas of bad back with fallen ground. The first sample taken was at station 2900 which was in a more stable area, and proceeded toward the portal. The sampling notes are very brief, but attention was paid to faults and stOpes and noticeable rock peculiarities adjacent to the sample localities. 8 All of the samples were taken from locations adjacent to stOped areas except numbers 1, 2, l6, and 31. Number 8 is from what appears to be the mineralized side of a fault. Location 12 shows cOpper stain only in the fracture planes. Sample 15 is from a badly faulted, highly fractured area with some fracture fillings. Sample 16 is from a badly faulted and fractured area too. Location 28 is an area with a poor back, possibly a highly fractured zone. Sample 30 is from an area adjacent to a fault. Petrographic Microscope Work Mineral Identification The gross mineralogy of the specimens was studied with a binocular petrographic microscope using eighty to two hundred power magnification for most of the work because of the fine grain size of the rock. The anorthite content of the plagioclase feldspar within the specimens was determined by using the Bittmann method with a five axis universal stage. Bock Textures The rock textures in the hand specimens and thin sections were observed with the naked eye, the binocular petrographic microscope, and an ordinary binocular microscope at low power to see nearly the whole specimen at one time. A monocular polarizing microscope with an automatic point counting stage attached was used to determine the percentage of amygdules,‘vesicles and veinlets (about 1200 to 1450 9 counts were made per slide). In this case the whole slide was traversed. Opaques The general occurrence and patterns of the opaque grains in the specimens were studied in the thin sections by using reflected light with the binocular microscope. Modal Analysis An automatic point counting stage was attached to a monocular petrographic microscope to determine the model analysis of the specimens. The counting was done on the first 500 mineral grains encountered on traversing the slides, this means that slightly less than one half of the tOp of the slide was represented. According to the 95 Per cent confidence interval chart in J. P. McCarthy's (1957, p 201) book the percentages determined should be within a range of from nearly zero to about eight per cent of being accurate for the whole slide. Reflecting Microscope Work Opaque minerals were identified and their inter-grain relationships were determined both with a fixed-stage metal- lographic microscope and a metallographic adapter on a petrographic microsOOpe. Polished sections were made from slabs of rock directly opposite the cut used for the thin sections in order to try to have nearly the same minerals exposed by both methods, only the width of the saw cut and surface grinding being missing. 10 X-ray Diffraction Ten samples were run on the x-ray diffraction equipment. These were whole rock samples run as a finely ground powder, and one sample was run as a polished section. Both cOpper and iron target tubes were used, one sample was run with both tubes to see which method produced the best results. The diffractograms were checked against a list of peaks of a number of suspected minerals, and against each other to see if there was a difference of identifiable peaks present from different samples. Sample Color Comparison Portions of the samples that were ground originally for x-ray determination were checked for color comparison and classification with the G.S.A. Color Chart. The powdered material was used instead of the hand specimens in order to obtain the total color instead of having the minor local variations in the specimens cause interference. The range of colors was then compared on a sample location chart (Fig. 55) to correlate with charts of other properties of the samples. Hand Specimens The polished sections were also used as hand specimens for the general categorizing of the specimens into several groups on the basis of general color, texture, etc. 11 OBSERVATIONS AND CORRELATION OF DATA Minerals Present and Percentages Minerals Present The following minerals are present in some or all of the samples; pyroxene, plagioclase, hematite, chlorite, epidote, pumpellyite, iddingsite, olivine, leucoxene, feld- Spar spherulites (g1ass?), quartz, sericite-saussurite, calcite, native copper, orthoclase-microcline (7). These minerals are seen in only a couple of isolated instances; serpentine, prehnite, and a zeolite amygdule filling (7). The mineral content of the samples is further discussed later. Figures A through 9 are photomicrographs of some of the minerals present. W. S. White (1968, p. 30“) refers to the Michigan native copper area as one of regional metamorphism of Coomb's prehnite-pumpellyite graywacke facies. Coombs, et. a1., (1959, p. 60) discusses the zeolite facies which has three stages, the third being the prehnite-pumpellyite stage. Winkler (1965) includes the pumpellyite-prehnite- quartz facies as a form of burial metamorphism wherein 'no additional thermal energy was supplied.“ (pp. 136 &l37) Pumpellyite, prehnite, calcite, albite, K-feldspar, chlorite and sphene are some of the minerals which are found in this grade of metamorphism (Winkler, p.1u0). These minerals are frequently found in the samples studied. Figure h. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. 12 Photomicrograph - pumpellyite in amygdule (thin section, sample 10) Photomicrograph - amy dule with pumpellyite in quartz, some epidote thin section, sample 28) Photomicrograph - amygdule with calcite, epidote, and quartz (thin section, sample 10) Photomicrograph - plagioclase and hematite about amygdule with epidote crystals in quartz (thin section, sample 29) Photomicrograph - altered plagioclase and hematite (thin section, sample 28) Photomicrograph - plagioclase and pyroxene (pol- arized light) (thin section,sample 20) 13 Table I Minerals Present (in %) opoo motoo sqetuteA setoIsaA a 'mev (setoeds pusq ut °qss tenets) JOddOO (L) (L) 'PIOJ‘X (6) 'III& 'BKWV “QII092 (a) eatuuead (L) eutquedaes actor's quJnssnes-aqrotses zqawnb (as-wt?) outth°uds aidivtbs eusxooneq OutAIIO oatsfiutvvl OQTKII°dmfld oaovtds °QIJOIH0 outnvwea sawtootiwtd eusxcsta 1J+ H \ N NH HHNHHHH HH~O HHHNHHHHHNH \N eesqgeeeeexqeewseeeeegeeeeeages sass egasgnsassnhsgsa sasaemogs H3“ H O O30 ON HH‘O O O O O O O O O O O O O HNN H O HOO H3 OOH mbHHn:Nenammoowmnoemmwwmmaomwae OOO...OOOOOOOOOOOOOOOOOOOOOOOOO “GOO“HQWNHHNMOomMOOHOHOFHNWNNNO HHN N H HN HH ma ONO (OOO N‘nO °®N Mb- Rm 0 N 3 N330 3 \ONNNW NO :O‘QOOH C O O O O O O O O O O O O O V\ O HMHH N HOOOO ON NHQHém N ‘1“ CD N N‘O‘O ONNO OQNN e e e e e e e e e e e e e O H N O OOH “OOH ”OOO H H O O O 3 O ... 3N CO V‘ O (D 0 O NN 3N e e e e e e e e e e e e 3O “\ N N M N 1n (“O OO OQONMOMNOHmwiNO‘OOOOQONNO®€O€DOOW OW NN‘O O\\O OP-MH O‘VNONSI‘HO' “NEH“: O‘HAOONO‘O HHM H HN H HH H H H H O3N ON N 3 N3 e e e e e e e e 0 OOO HO O H 00 O NOON-fiN‘O-fi‘O-QN‘OO“OOO‘OOQOSOO3-fl‘3 c.1000 ONH“QMH:HNOMNW‘AHO‘NOMWHOWNHMHVOOO NVO NON N N ONOONRO NOO‘O NOON N O O O O O O O O O O C O O . OO 20‘“ O O (“NO‘AONO NQO NOmO O :70‘ONO‘OMO‘OOFQOOOONOQQ‘OOO‘ONNOJ‘O“ WOMHnbO-‘l’“OOWMN‘ABOOHNOQMOONNHNQ Owémw—‘fO-fl'OBNOW‘O’OO‘O‘OOQQOMN‘O-fl’NO\ O O O O O O O O C O O O O O O O O O O O O C O O O O O O O O O HO‘OO‘OOOHWNHMOHOHOOMNNMK‘O‘ANQ'(“‘0 H H NHHH H HH H HN N NH ONN mecca N: onto m N N o .0. .0000 O. O... O O O 0 OOO oar-awe OH Ho-h-Hn H O O ((13 NOi?OOO-'TNOSIOQNh‘Od‘N-Q'OWWN‘O‘OSONOOO “NBC“‘ONHMO‘OHH‘ANN03NH‘OOHWNNONOHAHNNW HNH NH HHNH H ON:¢DN‘O(\#\OMV\O33‘ON8#OHON‘OQONO3030 NO OCD OVO\O\O“K\INV\®O\I\\O éO‘VNN MONO“V\NV\O\G; H H HH NHNHHNNHHH HH ase°s=s~°~°assegssecsseseeseese ONOHO‘OV‘OHHB OONHBOOanNNOONOWNM MM MNNNH MMMMNHHMNNNNHNNNHHN N3 OO‘QV.‘ OOOON NOON‘ON-‘O‘O‘OOOOOOV: NH HNM“OhmONOHNM3V\‘OI\OO\OHNMW\OL\®O\OH HHHHHHHHHNNNNNNNNNNMM JOQIRfl etdmws 15 Metallic Minerals Present The metallic minerals were studied in the polished sections with a metallographic microscOpe and a quick perusal was made of the thin sectiona.using oblique re- flected light. Most of the observations were made using polished sections. The metallics present in the samples vary in size from very small grains in the one or two micron size range to very large grains several hundred microns long. The size ranges present vary both within and among the samples. A few samples have only one size range present, but the rest have a range of two or more sizes. The majority of the specular hematite grains fall between the very small and medium or large sizes, and the native copper grains range mostly between the very small and small or medium sizes. Nearly all of the specular hematite occurs as scattered grains, ranging from very sparsely to closely scattered. Some occurs as scattered clusters. In a few samples very small grains occur in chain-like groups. Most of the grains are irregular in shape while some are rectangular (see Fig. 10). Some of the grains occur as veinlets, as rims for some large altered grains and small amygdules (see Figs. 11 and 12). Samples 1, 6, and 26 have a few large grains with noticeable twinning (see Fig. 13). Nonmetallic, earthy red hematite is also present and is very abundant. Most of the hematite is this variety and is only seen in the thin sections with reflected light. 16 The grains vary in size from very small to very large, some forming alteration rims around and through other minerals, such as olivine which has been altered to hematite and chlorite, and as rims of amygdules. Much of the earthy hematite is between other mineral grains and is sometimes associated with the native copper grains and is nearly always with the specular hematite. Copper occurs mostly.as either scattered individual grains or scattered clusters of grains and is not very abundant in most of the samples (see Fig. 1h and 15). About eight samples have cOpper either surrounding or filling amygdules (see Fig. 16). Veinlets including copper are found in eight of the samples (Fig. 17). Most of the samples have copper occurring in more than one form concurrently; i.e., grains, veinlets, amygdule fillings and rims. The amount of cOpper present in each sample was visually estimated by inspecting the polished sections with a regular binocular microscope using twenty power magnification and an auxiliary reflecting light source. The percentage of the field of view occupied by copper was estimated according to Figures B-h, 3-5, and 3-6 in L. E. Spock's Guide to the study of rocks, 2nd. ed., (pp. 32-34). An estimate was made each time the specimen was moved into an adjacent field of view, then the percentages were totaled and divided by the number of fields of view needed to completely cover the specimen. Only ten of the specimens average one half of one percent or more copper, of which six are over one percent. Figure Figure Figure Figure Figure Figure Figure Figure 10. 12. 13. 1h. 15o 16. 17. 1? Photomicrograph - rectangular hematite grains (polished section, sample 7) Photomicrograph - hematite rims around minerals (polished section, sample 28) Photomicrograph - hematite grains along rim of amygdule (polished section, sample 10) Photomicrograph - hematite grain showing twinning (polished section, sample 1) Photomicrograph - scattered native copper grains (polished section,samp1e 5) Photomicrograph - scattered native copper grains (polished section, sample 27) Photomicrograph - native cop er in amygdule (polished section, sample 17 Photomicrograph - native cop er in veinlet (polished section, sample 11 18 19 A percentage graph was made for cOpper (Fig. 37) and when it is compared to the other mineral percentage graphs it does not seem to indicate any correlatien pattern. Two types of examples which coincide with the theory that the copper was deposited later than the hematite were found. 1) Native cOpper, but not hematite, is frequently found within amygdules. 2) In at least one instance, in sample 20, copper appears to cut through a specular hematite grain, not the reverse. Carrels and Christ (1965) have shown in their figure 7.25 (p. 232), "The system Cu-Fe-S-O-H at 25°C and 1 atmos- 'um.“, that phere total pressure. The dissolved sulfur - lo native cOpper and hematite may coexist over a range of Eh from +0.15 to -0.65 and a range of pH of h to 15. This accounts for the presence of both the cOpper and the hema- tite if all of the conditions required were actually present. Mineral Percentage Correlations Twenty charts were drawn comparing the sample location versus the percentage of a particular mineral or group of minerals present (see Figs. 18-36). The group of charts of single minerals included; plagioclase, pyroxene, olivine, leucoxene, iddingsite, hematite, sericite-saussurite, pumpellyite, chlorite, calcite, and epidote. The combined mineral charts are for the following: pyroxene and olivine; hematite and iddingsite; sericite-saussurite and pumpellyite; sericite-saussurite, chlorite and pumpellyite; sericite- «Baussurite, chlorite, pumpellyite and epidote; plagioclase, 20 pumpellyite, sericite-saussurite, and epidote; olivine, pyroxene, iddingsite, and chlorite; and the ratio of plagio- clase, pumpellyite, sericite-saussurite, and epidote to olivine, pyroxene, iddingsite, and chlorite. For the comparison of the correlation charts, the twenty graphs of percentages of single or combined mineral contents of the thirty-one samples were compared with each other to see if a low percentage of one mineral correlated with either a high or a low percentage of another mineral at a particular sample location (Fig. 39). Attention was paid only to the qualitative measurement. If there was no correlation the location was left blank, if the two charts were in phase, i.e. increasing or decreasing at the same time, it was noted, as was the fact that the charts were out of phase, one increasing in value while the other de- creasing. Since there were thirty-one samples en twenty charts checked against nineteen others, there resulted in 5,890 locations taken twice, or 11,780 correlation points. The results showed that the majority of the comparisens were either in phase and/or out of phase and only a few showed no correlation at all. Some comparisons followed random unrelated trends, being partly in phase, partly out of phase, and the remainder following no pattern at all. Some of the minerals were graphed with their abundance versus that of another mineral or group of minerals that are possible substitutes or alteration products of them. (Fig. hO-hé). This was done to see if there is an inverse 21 relationship, when one increased the other decreased, hoping to show some type of linear correlation pattern. The graphs consist of the following; 1) sericite- saussurite and pumpellyite versus plagioclase; 2) sericite- saussurite, chlorite, and pumpellyite versus plagioclase; 3) plagioclase versus pyroxene and olivine; #) iddingsite and chlorite versus pyroxene and olivine; 5) pyroxene versus epidote and chlorite; 6) chlorite versus hematite and iddingsite; 7) chlorite versus pyroxene and olivine. Correlation is at best general to vague. Part of graph number three appears to show a direct relationship in abun- dances while another part can be interpreted to be vaguely inversely related. Graph number four shows a fairly wide- spread direct relatienship. No real correlation is shown by graph number one, the Points of intersection are widely scattered. Graph number two has a widely spread, general- ized inversely related pattern. The majority of the points in graph number five show a generalized directly propor- tional pattern. Graph six has no pattern at all, Just a cluster of points showing that in most of the samples the components are always present in quantities within about ten percent. The generalized pattern of graph number seven is that of direct proportion. Anorthite Content The plagioclase grains in the samples were compared to each other for anorthite ("An“) content (Fig. 50) and the results show that two thirds of the samples contain anorthite 22 in the range of thirty-four to thirty-seven percent and about one fourth have an "An“ content in the sixty-two to sixty-seven percent categroy. One sample has an anorthite content at fifty percent and is Joined by five samples that have a second range at fifty percent. Six samples show two ranges of anorthite percentages present. One of them has a range at thirty-six percent anorthite and one at fifty- seven percent anorthite content. The other five samples are those with a range at about fifty percent anorthite and their other range is in the sixty-two to sixty-seven per- cent anorthite content bracket. The plagioclases present are in the ranges of labrador- ite and andesine with some representation on the border be- tween the two, this may substantiate the albitization pro- cess refered to in the literature (Stoiber and Davidson, 1959, p. lb“? and others). When compared with the percent present graphs of the other minerals, the percent of 'An' present graph shows a similar pattern to the graph of pyroxene and olivine com- bined. Generally the samples in the labradorite range have a higher content of olivine and pyroxene, about 20 percent to about 30 percent, than the andesine rich samples which mostly have about 10 percent to zero percent. This suggests that with the albitization process there is a loss in the primary ferromagnesian mineral content in the parent rock. None of the other graphs shows so general an agreement. 23 Rock Textures Grain Size A number of the mineral grains in each specimen were measured in their longest and shortest dimensions. The long dimension grain sizes run from a lower limit of about .016 mm. to about 1.75 mm., most of the grains are quite small. The ranges of sizes of the pyroxene and plagioclase grains in each sample were plotted on logrithmic graphs (Fig. 51 and 52). The plagioclase range is fairly stable between .08 mm. and about .9 mm. The largest individual sample size range for plagioclase runs from .062 to 1.70 mm. Pyroxene size ranges vary and cover the field from .016 to 1.60 mm. with no apparently "average“ range. The shortest individual range is from .250 to .320 mm., while the largest individual range is from .016 to .340 mm. The ranges of sizes of pyroxene and plagioclase do not appear to correlate with each other, that is within one sample one mineral may have a short range on the large end of the scale while the other has a long range in the middle of the scale, or vice versa, etc. Grains of some other minerals were also measured and are mostly of a fine grain size. These minerals were not plotted on correlation graphs. Amygdules, vesicles, and fractures The amygdules within the samples contain the following either individually or in various combinations: feldspar spherulites (or glass), chlorite, calcite, epidote, feldspar 2h (microcline of the literature?), hematite (as a ring), copper, pumpellyite, quartz, and sericite-saussurite. The shapes of the amygdules and vesicles in most cases are round to elliptical with an occasional one having some strange shape. In a few samples the elongated amygdules appear to be somewhat aligned as if by flowage in the molten lava. The longest and shortest dimensions of many of the amygdules and vesicles were measured and the range of sizes of the largest dimension were plotted on a graph (Fig. 53). The size range is from .190 mm. to 8.800 mm. and two of the largest ranges within single samples are from .2uo mm. to 6.600 mm. and from .600 mm. to 8.800 mm. When plotted on the logrithmic size range graph and compared with the pyroxene and plagioclase graphs, the amygdule and vesicle size is more consistent than pyroxene but less constant than plagioclase and does not seem to correlate with either of the two mineral grain sizes. Fracture filling veinlets were noted in some of the samples. They contain many of the minerals found in the amygdules and vary in width both within a particular veinlet in a sample and between samples. The percentage of the sample that is made up of amygdules, vesicles, and veinlets was tabulated on a graph (Fig. 38) and found to range from about one half of one percent to thirty-three percent of the sample area. 25 When correlated against the graphs of mineral percentages it is seen that the graph of the percent of amygdules, vesicles and veinlets is predominately in direct phase with the graphs of hematite; pumpellyite; hematite and iddingsite; plagioclase, pumpellyite, sericite-saussurite, and epidote; calcite; and epidote. There is an out of phase, or opposite, correlation with pyroxene; chlorite; pyroxene and olivine; olivine, pyroxene, iddingsite and chlorite; and the ratio of plagioclase, pumpellyite, sericite-saussurite, and epidote to olivine, pyroxene, iddingsite, and chlorite. The rest of the graphs show a mixture of the two phases. Direct comparison graphs were made between the percent of amygdules, vesicles and veinlets and; l) sericite- saussurite, chlorite and pumpellyite; 2) sericite-saussurite chlorite, pumpellyite, calcite, and epidote; 3) chlorite (Figs. #8, #9, 47). Part of number one may be interpreted to be in direct preportion while the rest of it indicates an inverse proportionality. Part of number two is directly proportional while the rest of the graph shows no pattern. Number three shows the best pattern and it is mostly that of an inverse proportion, which is the Opposite of what the writer had expected since chlorite is thought of as an alteration mineral and an increase in amygdules, vesicles and veinlets would suggest an increase in porosity and thus increase the ease of passage of hydrothermal solutions which could increase the alteration of the rock. However, the increase in porosity evidently did not increase the 26 permeability and aid in the alteration of the rock in these sample localities. Rock Color The sample color graph was checked against the sample mineral percentage graphs and the anorthite content graph to see if there was an apparent correlation between them. No correlation was seen. Three ternary diagrams were constructed (Figs. 56, 57. 58) using chroma, hue, and value to cover the color desig- nations of the majority of the samples. Most of the samples appear to cluster in a small area, especially when it is considered that some points represent up to seven samples with that color designation. This shows that while the color changes from sample to sample, most of the samples fall into only a couple of color classifications and appar- ently it does not reflect the change in any one constituent. Hand Specimens The hand specimens that had been made into polished sections may be arranged into seven groups having similar megascopic appearance, i.e., general color, texture, etc. All but two specimens fit into groups containing two or more samples. Group A has five members, numbers 1, 2, 7, 30, 31; group B has ten members, numbers 5, 6, 12, 13, 15, 17, 22, 23, 26, 28; group C has four members, numbers 8, 9, 10, 18; group D has three members, numbers h, 11, 27; group E has three members, numbers 3, 1h, 19; group F has two members, 27 numbers 16, 21; group G also has two.members, numbers 24, 25; and samples 20 and 29 are independent. The generalized thin section descriptions of the samples within each group were compared and in most cases they are quite similar as to approximate percentages of mineral assemblages present, type of plagioclase, abundance of amygdules and vesicles, and the grain size range found in the rest of the group. The group identifying letter was then placed above the sample number in sequence and a graph was drawn (Fig. 54), then it was compared to the percent composition graphs pre- viously drawn. The closest comparable graph is that of the combined ferromagnesian minerals, whereas all of those in each group have approximately equal percentages of ferro- magnesian minerals present. SAMPLE GROUP DESCRIPTIONS AND CORRELATIONS The following generalized descriptions of the 7 sample groups include; 1) five assemblages, each of which is ranked against the same assemblage in the thirty-one samples as to mineral content percentage of the total individual sample, and 2) the range in grain size of three assemblages. The assemblages used for percentages are: l) plagioclase; 2) ferromagnesian minerals, including pyroxene and olivine; 3) alteration minerals, which includes sericite-saussurite, chlorite, and pumpellyite; h) iron minerals, which includes 28 hematite and iddingsite; 5) and the total of amygdules and vesicles. The size ranges are between the longest measured dimension of the smallest and of the largest grains measured in each of the three assemblages which are; l) plagioclase grains, 2) pyroxene grains, 3) and amygdules and vesicles. Descriptions and correlations of the individual samples which comprise the groups may be found in Appendix A. The groups D, E, and G are small groups that do not have as much agreement in percentages of the minerals present in them as the other groups here. Group A Most of the specimens have a medium to high content of andesine plagioclase (17.6 - 38.8%), a low ferromagnesian mineral content (5.5 - 13.0%), a low to medium altered mineral content (22.u - 30.3%), a medium to high medium iron mineral content (16.2 - 27.3%), and a low to medium amygdule content (5.9 - 12.4%). Plagioclase grain sizes vary from .096 mm. to 1.41“ mm., pyroxene grains range from .160 mm. to 1.600 mm., and the amygdules and vexicles vary in size from .272 mm. to 3.200 mm. Group B Both andesine and labradorite plagioclase are present in this group, sometimes both in the same sample. When taken separately the plagioclase percentages vary over a wide range, but when plagioclase and the alteration mineral contents are considered together their total is nearly 29 constant throughout the group, varying from 47.2 to 58.4%. The ferromagnesian minerals are medium to high in abundance (16.4 - 26.6%). In all but one case the iron minerals are in the medium low to medium range (12.1 - 23.4%), and the one exception is in the low range (6.6%). The amygdule and vesicle volume varies from very low to low (0.6 - 5.5%). The plagioclase grains vary in size from .080 mm. to .896 mm., pyroxene grain sizes range from .016 mm. to 1.248 mm., and the long dimensions of the amygdules and vesicles range from .128 mm. to 1.920 mm. Group C The andesine plagioclase content ranges from low to high (10.6 - 31.9%). Three of the four specimens have alter- ation mineral contents ranging from low to medium (22.0 - 29.6%), but one has a high medium content (41.2%), however, if the plagioclase and the alteration mineral contents are considered together they range from 46.5% to 61.5%. The ferromagnesian minerals range in abundance from very low to low (0.2 - 9.0%), the iron minerals range from medium to high medium in abundance (21.0 - 27.4%), and the amount of amygdules and vesicles varies from medium to high (10.9 - 21.4%). Plagioclase grain sizes vary from .080 mm. to 1.008 mm., pyroxene grains range from .176 mm. to .800 mm., and the sizes of amygdules and vesicles range from .528 mm. to 4.240 mm. 30 Group D The labradorite and andesine plagioclase varies greatly in abundance from very low to medium (1.6 - 22.6%), the ferromagnesian mineral content ranges from very low to very high (6.4 - 28.8%), the alteration minerals vary from medium to very high (34.0 - 48.6%), the iron minerals range from very low to medium (8.3 - 21.8%), while the low amygdule and vesicle content is the most constant variable (2.6 - 5.9%). The plagioclase grain sizes vary from .064 mm. to 1.680 mm. in length, the pyroxene grains range from .016 mm. to .336 mm., and the largest diameters of the amygdules and vesicles range from .240 mm. to 1.640 mm. Group E The andesine plagioclase varies from medium low to high in abundance (19.4% - 38.6%) to give a total feldspar con- tent ranging from 19.4% to 50.2%. The ferromagnesian minerals vary from complete absence to very low in abundance (0.0% - 4.2%), alteration minerals are low in content (16.5 - 22.0%), the presence of iron minerals ranges from medium to very high (20.3 - 37.9%), and the amygdules and vesicles are high to very high in abundance (20.6 - 26.4%). The plagioclase grain sizes range from .112 mm. to .880 mm., and the largest diameters of the amygdules and vesicles range from .416 mm. to 6.496 mm. Group F The andesine plagioclase content is medium high _ 31 (25.0 - 31.4%), the ferromagnesian mineral content is very low (0.6 - 5.2%), the alteration minerals are medium in abundance (28.8 - 34.6%), as are the iron minerals (23.2 - 24.8%), and the amygdule and vesicle abundances are low medium and high (8.2 - 17.7%). The plagioclase grains range in size from .096 mm. to .768 mm. in length, the pyroxene grain sizes are not really applicable, and the large dimen- sions of the amygdules and vesicles range from .272 mm. to 3.680 mm. Group G The andesine plagioclase varies in abundance from medium low to medium high (18.4 - 27.6%), the unknown feldspar content is nearly the same (8.4 - 9.8%), the ferro- magnesian minerals are very low in content (0.6 - 1.2%), the iron minerals range from medium to high in abundance (20.5 - 28.6%), as do the amygdules and vesicles (11.6 - 17.2%). The plagioclase grains range in size from .096 mm. to .992 mm., the pyroxene grain size range comvers .096 mm. to .224 mm., and the longest dimensions of the amygdules and vesicles varies from .240 mm. to 6.560 mm. SUMMARY AND CONCLUSIONS Thirty-one samples were collected over a length of 2900 feet of drift along a horizontal structural contour within the Knowlton amygdaloid in the Caledonia mine, Ontonagon County, Michigan. The intent of the study was 32 to determine the degree of homogeneity or heterogeneity within a vertically homogeneous sample area by trying to identify patterns of minerals, textures, structures, and other characteristics within the rocks. Ordinary, petrographic, and metallographic microscopes were used to study thin and polished sections made from the samples to identify their mineralogy, modal analysis, and textures. The polished sections were also used as hand specimens for a rough megasc0pic classification, and adjacent slices of material were ground to a fine powder and used for rock color determinations. The percentage of a mineral and groups of minerals present within a specimen was tabulated and correlated with the amount of the same mineral or minerals present in the other samples. Cross correlations were made between asso- ciated minerals, etc., and the amount of the specimen con- sisting of amygdules, vesicles, and veinlets. The several grain sizes and their distribution between samples were also studied. It was observed that twenty-nine of the thirty-one samples appear to mostly confine themselves to seven major groups, based upon megasc0pic appearances, which are some- what similar in microscOpic characteristics. These simi- larities, better in some groups than in others, reoccur, but not in any orderly manner, giving no real pattern but suggesting some type of repetition. 33 Professional Paper 144 states that within a number of the mines in the Mass area the Knowlton amygdaloid ("lode") has been worked and is of the fragmental, or brecciated, amygdaloid type with an intermediate composition near the andesite end of the basalts (p. 213). Butler and Burbank (pp. 31 and 32) believe that the origin of the fragmental or brecciated flow tOps took place in the following manner: The inclusion of amygdaloid fragments partly resorbed in the traps under the amygdaloids seems to indicate clearly that the fragmental tOps were formed while the interior portions of the flows were still fluid and presumably still moving. The irregular piling up of the fragments on the flow can probably be best explained by flow forces similar to those in a moving floating ice field. Such movement would result in much abra- sion of the fragments. The fact that where the fragments are piled above the general level they also sink deeper into the flow indicated that they were piled up while the underlying lava was still fluid enough to permit the sinking of the material, as ice sinks deeper where it is piled higher above the water surface. It seems likely, therefore, that flow move- ment was a factor in producing the rough tOps as we now see them, but it evidently was not the sole factor, because all the flows must have been moving and in general over surfaces of the same type with the same gradient, some solidifying as smooth t0ps, some as rough. There must, there- fore, have been some difference in the lava itself. That the difference was not necessarily very great is indicated by the fact that a top may pass from one type to another within a very short distance. That the composition as we now find it was not the cause is indicated by the close similarity in composition of flows with tops of different types and the presence of tops of different types on parts of the same flow. That the amygdaloid is fragmental accounts for the fact that there does not seem to be a definite pattern of occurrence along the strike of the lode. There are some 34 similarities between some of the samples and they fall into the same megasc0pic groups, so these are apparently pieces of blocks of brecciated material in one group and inter- stitial material in another, etc. Since the composition within the breccia blocks can vary with the distance in from the edges due to alteration and/or cooling rates, there can be several rock types encountered on a repetative basis along strike. Small scale textural variations are notice- able in a few of the hand specimens and a couple of thin sections so the variations along the wall of the drift could be numerous. No pattern seems to be present that would be a guide to the direction of an increase or decrease in the amount of copper in the lode. The abundance of cOpper seems to be an independent variable and not predictable by any of the characteristics of the rock studied herein. This agrees with what Butler and Burbank said in W (p. 149). RECOMMENDATIONS A horizontal pattern may appear in the Knowlton lode if another sampling scheme were used. Possibly a composite sample from each location, as was used by Stoiber and David- son, or some different interval between samples or a con- tinuous channel sample would disclose some type of mineral- ogical or textural pattern. 35 A large scale study of possible horizontal patterns or zoning as suggested in 1935 by T. M. Broderick may prove productive. One problem with this would be finding outcrOps or drill core samples that were undisputably from the same approximate horizontal horizon of the same flow. No matter what the size of the scale of the study, it must be remembered that the Knowlton lode, and several others, are brecciated flows which are mixtures of various rock types in variable proportions complicating a study of rock homogeneity. The study of non-brecciated flow taps may produce more of a horizontal pattern of homogeneity. Further study of the rough megascopic grouping of specimens into groups with similar microscopic properties may prove to be an aid in the quick classification of specimens. Known specimens are needed for this classifi- cation method, or one sample from each group could be studied in detail to provide a fair amount of general infor- mation for the whole group. Unfortunately, the consistancy of similarities is not constant in all groups, it varies from very good to somewhat vague. BIBLIOGRAPHY BIBLIOGRAPHY Barth, T. F. W., 1962, Theoretical Petrology, 2nd ed., John Wiley, N.Y., 416 p. 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E., 1913, "Michigan COpper Industry in 1912," MineralLResources of Michigan, 1912, Publication 13, Series 10, Mich. Geol. and Biology Survey, Lansing, Michigan. Hore, R. E., 1912, "The Copper Industry of Michigan," Mineral Resources of Michigan, 1910, Publication 8, Series 67*Michigan Geol. and Biology Survey, Lansing, Michigan. 39 Irving, R. S., 1883, "The COpper Bearing Rocks of Lake Superior," U.S. Geol. Survey, Mon. 5, 464 pp. Johannsen, A., 1939, A descriptive petrography of the igneous rocks, 2nd ed., Vols., Univ. Chicago Press, Chicago. Kerr, P. F. 1959, Optical Mineralogy, 3rd ed., McGraw-Hill N.Y., 442 pp. Laffitte, P., 1962, "Mechanism and Duration of Vein De osit Formation," goon. Geol., V. 57, No. 4, pp. 587-59 . Lane, A. C., 1935. "Differentiation in Traps and Ore Depo- sition," (disc.) Econ. Geol., V. 30, pp. 924-927. Lane, A. C., 1911, "The Keweenawan Series of Michigan,” Michigan Geol. Survey Publication 6 (Geol. Survey Series 4), 2 vols., 983 pp. Lindgren, W., 1933, "The Lake Superior Copper Deposits," in Mineral Deposits, 4th ed., p. 517-526, McGraw-Hill, NoYo. 930 pp. Martin, Helen, 1936, "The Centennial Geological Map of the Northern Peninsula of Michigan,” Publication 39, Series 33, Mich. Geol. Survey, Lansing, Michigan. Martin, Helen and Straight, Muriel, 1956, "An Index of Michigan Geology," Publicationg50, Michigan Geol. Survey, Lansing, Michigan. Mason, Brian, 1966, Principles of Geochemistry, 3rd ed., John Wiley & Sons, Inc., N.Y. McCarthy, P. J., 1957, Introduction to statistical repsoning, McGraw-Hill, N.Y., pp. 201-205. McKinstry, Hugh E., 1948, Mining Geology, (scattered refer- ences), Prentice Hall, Englewood Cliffs, N. J. McKinstry, H. E., 1951, "Differentiation in . . . Keweenawan series: (rev.) Econ. Geol., V. 46, pp. 658-659. Meshref, W. M. and Hinze, W. J., 1970, Geologic interpreta- tion of aeromagnetic data in Western Upper Peninsula of Michigan, Report of investigation 12, Mich. Geol. Survey, Lansing, Michigan, 25 pp. Moorhouse, W. W., 1959, The Study of Rocks in thin sections, Harper & Row, N.Y., 514 pp. Niggli, P., 1952, "The chemistry of the Keweenaw lavas," gm. Jour. Sci., V. 250a, part 2 (Bowen vol.), pp. 381- 12. ' 40 Park, Charles, F., Jr., MacDiarmid 1964, Ore De osits, pp. 64, 181, 313, 314, 327-32é, 454, Freeman, San Francisco, California. Parker, Pierce D., 1962, "Some Effects of Environment on Ore Deposition," Econ. Geol., V. 57, no. 3, pp. 293-324 Pollock, J. P., Schillinger, A. W. and Bur, T., 1960, ”A Geochemical anomaly associated with a glacially trans- ported boulder train, Mt. Bohemia, Keweenaw County, Michigan,” in Int. Geol. Cong. XXI Session, pp. 20-27. Rankama, Kalervo and Sahama, T. C., 1950, “COpper (ch. 36)," geochemistry, Univ. of Chicago Press, Chicago, PD. 95'701e Riley, Charles M., 1959. Our Mineral Resources, pp. 92-96, Wiley, N.Y. Routhier, P., 1963, ”Les gites de cuivre natif du Lac Superieur (Michigan)," in Les gisemgnts pepgllifezes- Geolo ie et principes de recherch s pt. 1 Masson et CIET-éaris, pp. 640-643:_646:—-_£Ld ' Schouten, C., 1962, Determination Tables for Ore Microscopy, Elsevier Pub. Co., N.Y., 2 2 pp. Schwartz, G. M., 1934, "Paragenesis of the Oxicized Ores of Copper," Econ. Geol., V. 29, pp. 55-76. Short, M. N., 1940, Microscopic Determination of the ore minerals, U.S.G.S. Bull. 91 , 3 pp. Singewald, J. T., Jr., 1928, "A Genetic Comparison of the Michigan and Bolivian Copper Deposits," Econ, Geol., V. 23, pp. 55-61. 3P1P0ff, K., 1942, "Geology of the Firesteel River Area," open file report, Michigan Geol. Survey., Lansing, Michigan. Spock, L. E., 1961 Guide to the study-of rocks, Harper & Row, N.Y., 298 pp. Stevens, Horace J., 1911, The Copper Handbook, published by the author, V. 10, Houghton, Michigan. Stoiber, R. E., and Davidson, E. S., 1959, 'Amygdule Mineral Zoning in the Portage Lake Lava Series, Michigan Copper District," Econ. Geol., V. 54, no. 7, pp. 1250- 1277. no. 8, pp. 1444-1460. 41 Stoiber, R. E., and Davidson, E. S., 1955, "Mineral Zoning in the P.L.L.S. Michigan Copper District," (abs.), AIME fibstracts, Mining, Geology & Geophysics Division, pp. 2 “250 Uytenbogaardt, W., 1951, Tables for micrOSCOpic identifi- cation of ore minerals, Princeton Univ. Press, Prince- ton, N.J., 242 pp. Van Hise, C. R. and Leith, C. K., 1911, "The Geology of the Lake Superior Region," U.S. Geol. Survey, Mon. 52, pp. 367-427. 573-591. Warren, Harry V. and Delavault, Robert E., 1959, "Readily Extractable Copper in Eruptive Rocks as a Guide for Prospecting," goon. Geol., V. 54, no. 8, pp. 1291-1297. Weege, R. J., and Schillinger, A. W., 1962, ”Footwall mineralization in Osceola Amygdaloid, Michigan Native COpper District," A.I.M.E. Tr., V. 223, pp. 344-350, Soc. of Mining Eng. Wells, R. C., 1925, "Chemistry and Deposition of Native Copper from Ascending Solutions," U.S.G.S. Bull. 778, 71 PPo White, W. S., 1966, "Tectonics of the Keweenawan Basin, Western Lake Superior Region," U.S.G.S., Shorter Contrib. to Geol., Prof. Paper 524-E, 23 pp. White, W. S., 1968, "Keweenaw Point, Michigan," Ore Deposits of the U.S. 193331967, CH. 1 , A.I.M.E., New York. White, W. 3., 1960, "The Keweenawan Lavas of Lake Superior, an example of flood basalts," Am. Jour, Sci., Bradley White, W. S., 1956, "Regional Structural Setting of the Michigan Native COpper District," p. 3-16, disc - p. 18-19, in Snelgrove, A. K., Editor, Geological Exploration, Institute on Lake Superior Geo ogy, Houghton, Michigan, 109 p. White, W. S., 1952, "Imbrications and initial dip in a Keweenawan conglomerate bed,” JourLASed. Ped., V. 22, pp0 189’1990 White, W. 5., and Wright, James C., 1960, "Lithofacies of the Copper Harbor Conglomerate, Northern Michigan," in Short Papers in the Geol. Sciences, Geol. Survey Research, U.S.G.S. Prof. Paper 400-B, p. B5-B8. 42 Williams, S. A., 1962a, "Stability Relations and Paragenesis of COpper Oxides and Chlorides at Algomah Mine, Ontonagon County, Michigan,” Econ. Geol., V. 57, pp. 111-113. Williams, S. A., 1962b, "Paramelaconite and Associated Minerals from the Algomah Mine, Ontonagon County, Michigan," Am. Min., V. 47, pp. 778-779. Wilson, Chester H., 1967, "Petrology of the Algomah Mine Area, Ontonagon County, Michigan," M.S. Thesis, M.S.U., PP- 50. Winkler, H. c. F., 1965, Petrogenesis of Metamorphic Rocks, Springer-Verlag New York Inc., N.Y., 220 pp. Zinn, Justin, 1942, "The Adventure Mining PrOperty," Open File Report (lost?) Michigan Geol. Survey, Lansing, Michigan. Zinn, Justin, 1930, "Petrography of the Keweenaw lava Flows of Michigan," M.S. Thesis, Michigan College of Mining and Technology, Houghton, Michigan. APPENDICES APPENDIX A INDIVIDUAL SAMPLE DESCRIPTIONS AND CORRELATIONS The following generalized descriptions of the samples include; 1) five assemblages, each of which is ranked against the same assemblage in the other thirty samples as to mineral content percentage of the total individual sample, and 2) the range in grain size of three assemblages ranked in the same manner as above. The assemblages used for per- centages are: l) plagioclase; 2) ferromagnesian minerals, including pyroxene and olivine; 3) alteration minerals, which includes sericite-saussurite, chlorite, and pumpelly- ite; 4) iron minerals, which includes hematite and idding- site; 5) and the total of amygdules and vesicles. The size ranges and scales are between the longest measured dimension of the smallest and of the largest grains measured in each of the three assemblages which are; l) plagioclase grains, 2) pyroxene grains, 3) and amygdules and vesicles. In these descriptions range refers to the sizes encountered in the specific sample while the scale is the relative comparison to the total sizes encountered in all of the samples. The scale for plagioclase is from .064 mm. to 1.680 mm., the pyroxene scale is from .016 mm. to 1.600 mm., and the scale for amygdules and vesicles is from .192 mm. to 8.800 mm. 43 44 Sample C-l-2900-66 A moderate red, diabasic, ophitic, porphyritic basalt that has a very high (38.8%) content of andesine plagio- clase, a low ferromagnesian mineral content (10.2%), a low to medium alteration mineral content (25.8%), and a medium iron mineral content (17.4%). Only 5.9% of the rock mass consists of amygdules and vesicles, a low amount. The range of grain sizes is varied, the plagioclase range is average (.128-.672 mm.), the amygdule size range is small (.464- .800 mm.) and on the small end of the scale, the pyroxene grain size range is small but on the large end of the scale with grains ranging in size from .784 mm. to 1.488 mm. in length. Sample C-2-2800-66 A pale brownish gray, diabasic, ophitic, porphyritic, amygdaloidal basalt with a medium high andesine plagioclase content (32.4%), a low ferromagnesian mineral content (13.0%), a low alteration mineral content (23.2%), and a medium iron mineral content (16.2%). About 10.8% of the rock mass con- sists of amygdules, vesicles, and veinlets, an apparently medium content. The grain size range varies with plagio- clase being average (.144-.960 mm.), amygdule size small to medium (.352-1.44 mm.) on the small and of the scale, and pyroxene size small (.720-l.280 mm.), but on the large end of the scale. 45 Sample C-3-2700-66 A medium grayish red, diabasic, porphyritic, amygda- loidal basalt. The andesine plagioclase content is medium low (20.7%), and there is a significant content (11.6%) of what appears to be an untwinned feldspar, noticeable along veinlets and in amygdules, likely the K-feldspar or micro- cline mentioned in the literature (Butler and Burbank, 1929, and others). All of the feldspar in this sample is cloudy with dust size inclusions. The ferromagnesian mineral con- tent is non-existant (0.0%), and the alteration mineral con- tent is 1ow (17.3%). The iron minerals are more abundant in this sample than in any of the other thirty samples (37.9%). Amygdules and vesicles account for 9.1% of the volume of the rock while veinlets make up another 12.4% to a total of 21.5% of the specimen, a relatively large amount. The andesine grains are of average size (.112-.880 mm.), while the amygdule and vesicle size range is low (.416- .960 mm.) and on the low end of the scale. Sample C-4-2600-66 A light olive gray, porphyritic, basalt, much of which appears to be very fine grained and severly altered. The labradorite plagioclase content is the lowest (1.6%) of the thirty-one specimens, the ferromagnesian mineral content is medium (22.1%), the alteration mineral content is one of the highest of those in the study (48.6%), and the iron minerals are medium in abundance (21.8%). Amygdules and 46 vesicles account for only about 0.1% of the sample while veinlets equal 2.7% giving a total of only 2.8%, a very low range of abundance. The plagioclase grain size range is average (.144-.880 mm.) while the pyroxene grain size range is about medium (.016-.128 mm.), but it is on the very low end of the scale of those samples measured. Sample C-5-2500-66 A medium greenish gray, diabasic, porphyritic, amygda- loidal basalt. This sample appears to have both andesine and labradorite plagioclase which combine to give a low plagioclase content (8.6%). The ferromagnesian mineral con- tent is medium (20.0%), the alteration mineral content is very high (44.5%), and the content of iron minerals is medium to low (12.1%). Amygdules and vesicles amount to a low of 5.5% of the rock mass. Grain size of the plagio- clases is average (.128-.800 mm.), while the pyroxene size range is a large medium (.016-.240 mm.), but on the low end of the range. The amygdules and vesicles have a medium size range (.640-l.920 mm.) near the low end of their size scale. Sample C-6-2400-66 A light brownish gray, diabasic, porphyritic, ophitic basalt. The plagioclase in this sample is andesine, near the labradorite border, and constitutes a very low per- centage of the rock, only 6.4%. The ferromagnesian mineral 47 content is medium (20.8%), the alteration mineral content is the highest for any of the samples studied (50.6%), and the iron minerals are of a medium range of abundance (17.6%). The relative abundance of amygdules and vesicles and vein- lets is very low in this sample (2.5%), it is nearly equally divided between the amygdules and vesicles (1.4%) and the veinlets (1.1%). The plagioclase grain size range is about average (.128-.512 mm.), the pyroxene range is low (.112- .288 mm.) but in the middle of the scale, and the amygdule and vesicle size range is medium (.384-1.360 mm.) while near the low end of the scale. Sample C-7-2300-66 A light brown, diabasic, porphyritic, amygdaloidal, ophitic basalt, The andesine plagioclase content is high (35.8%), the ferromagnesian mineral content is low (5.5%), the alteration minerals are medium in abundance (30.3%), as are the iron minerals (17.0%). A medium number of amygdules and vesicles appear to be present (8.2%). The size range of the plagioclase grains is medium (.256- .528 mm.), the pyroxene range is medium (.176-1.120 mm.) and is on the large end of the scale, and the amygdule and vesicle size range is medium (.448-l.200 mm.) on the low end of the scale. Sample C-8-2290-66 A medium brownish gray, diabasic, amygdaloidal, 48 porphyritic basalt. The plagioclase is of the andesine variety and the content is high (28.2%), there is a low amount (2.8%) of untwinned feldspar present, the ferro- magnesian mineral content is practically absent (0.2%), alteration minerals are low in abundance (22.0%), and the iron minerals are medium in abundance (21.0%) as are the amygdules and vesicles (15.0%). The plagioclase size range is average (.128-.640 mm.) and the amygdule and vesicle size range is large (.608-8.800 mm.), tending to be on the high end of the scale. Sample C-9-2165-66 A light brownish gray, diabasic, amygdaloidal, por- phyritic basalt. Andesine plagioclase is medium high in abundance (31.9%), the ferromagnesian minerals are very low (2.6%), the alteration mineral content is medium (29.6%), and the iron minerals are medium in abundance (22.3%) as are the amygdules and vesicles (12.3%). The size range of the plagioclase grains is about average (.192-1.008 mm.), the pyroxene range is low (.176-.368 mm.) in the middle of the scale, and the amygdule and vesicle range is fairly large (.704-4.240 mm.) toward the large end of the scale. Sample C-10-2100-66 A medium brownish gray, diabasic, porphyritic, amygda- loidal basalt. Andesine plagioclase is medium low in conten: (21.2%), ferromagnesian minerals are nearly absent (0.8%). 49 alteration minerals are medium in abundance (25.3%) as are the iron minerals (25.3%). The content of amygdules and vesicles is quite high (21.4%). The size range of the plagioclase grains is moderately large (.080-.960 mm.) in the middle of the scale, while the amygdule and vesicle size range is large (.272-2.960 mm.), but on the lower three-fourths of the scale. Sample C-11-2000-66 A light greenish gray, porphyritic, amygdaloidal basalt. The plagioclase grains are very fine and altered and appear to be labradorite and are medium low in abundance (17.0%). The ferromagnesian mineral content is extremely high (28.8%), the alteration mineral content is medium (34.0%), the iron minerals are very low in abundance (8.3%), and the amygdule and vesicle content is also quite low (1.8%) as is the veinlet percentage (0.8%). The plagioclase size range is very small (.128-.208 mm.) and is on the small end of the scale. Pyroxenes in this sample have the largest range in size (.016-.304 mm.) of any of the samples, but it tends to be on the lower two-thirds of the scale. The size range for the amygdules and vesicles is about average (.240-1.440 mm.) and is on the low end of the scale. Sample C-12-1900-66 A light olive gray, diabasic, porphyritic, cphitic, amygdalbidal basalt. The altered labradorite plagioclase 50 grains are very abundant (34.8%), the ferromagnesian min- erals are very abundant (26.6%), the altered mineral content is very low (18.8%), and the iron minerals are very low in abundance (12.8%), as are the amygdules and vesicles (2.9%). The size range of the plagioclase is average (.080-.512 mm.), the pyroxene size range is very large (.048-1.248 mm.) and in the middle of the scale, and the amygdule and vesicle size range is very small (.800-1.280 mm.) in about the middle of the scale. A Sample C-13-1800-66 A medium brownish gray, diabasic, amygdaloidal, por- phyritic, ophitic basalt. The andesine plagioclase is medium high (30.2%) in abundance, the ferromagnesian content is medium (16.4%), as is that of the alteration minerals (26.6%) and the iron minerals (19.2%), while the content of amygdules and vesicles is low (5.0%). The size range of the plagioclase grains is average (.080-.592 mm.), that of the pyroxene is medium (.144-.624 mm.) near the large end of the scale. The size range of the amygdules and vesicles is just below average (.192-.896 mm.) and is slightly lower on the scale than any of the other samples. Sample C-14-1700-66 A light brownish gray, diabasic, porphyritic, amygda- loidal basalt. This sample has a very high andesine plagio- clase content (38.6%) along with a significant content 51 (11.6%) of what appears to be a different, untwinned, feldspar, probably the microcline - orthoclase mentioned in some of the literature (Butler and Burbank, 1929). Ferromagnesian minerals are all but absent from this sample (0.8%), alteration minerals are less abundant (16.5%) than in other locations and the content of ironminerals is about medium (20.3%). The abundance of amygdules and vesicles is quite high (20.6%). The size range of the plagioclase grains is about average (.176-.752 mm.), and that of the amygdules and vesicles is very large (.544- 6.496 mm.), tending to cover most of the larger end of the scale. Sample C-l5-1600-66 A light brownish olive gray, diabasic, porphyritic, amygdaloidal basalt. The plagioclase I'An" content appears to be varied from about the middle of the labradorite range to just into the andesine range and is medium high in abun- dance (32.7%). The ferromagnesian mineral content is medium (19.1%), as is the content of the alteration minerals (25.1%) and iron minerals (15.3%). Amygdules and vesicles are nearly absent (0.6%). The size range of the plagioclase grains is a little shorter than average (.128-.480 mm.) in the middle of the scale. Pyroxene grains in this specimen have the shortest size range (.256-.320 mm.) of any of the specimens studied and it is just above the middle of the 52 scale. Amygdules and vesicles have a very short size range (.368-.848 mm.) near the small end of the scale. Sample C-16-1500-66 A pale grayish red, porphyritic, vesicular, amygda- loidal basalt. The andesine plagioclase content is medium high (31.4%), the ferromagnesian minerals nearly absent (0.6%), alteration minerals medium (28.8%), as are the iron minerals (24.8%). Amygdules and vesicles are quite high in abundance (15.9%), and veinlets are noticeable (1.8%). The plagioclase grain size range is average (.128-.720 mm.) and that of the amygdules and vesicles is quite large (.320- 2.752 mm.), but within the lower three-fourths of the size scale. Sample C-17-1400-66 A greenish gray, porphyritic, amygdaloidal basalt. The andesine plagioclase content is medium high (27.0%), there also are many very small microlites of feldspar that are too severely altered to get an extinction angle on to figure out the anorthite content. The ferromagnesian minerals are medium in abundance (19.2%), as are the alter- ation minerals (31.4%). The iron minerals are the lowest in abundance (6.6%) in this sample, and the content of amygdules and vesicles is quite low (5.5%). The plagioclase grains cover an average size range (.112-.896 mm.). The range of the pyroxenes is about medium (.112-.400 mm.), 53 just on the low part of the high end of the scale. Amygdules and vesicles occupy a short range (.336-.832 mm.) just below the middle of the scale. Sample C-18-1300-66 A light brownish gray, diabasic, porphyritic, amygda- loidal, ophitic basalt. The low plagioclase content (10.6%) is andesine in composition. Ferromagnesian minerals are fairly low in abundance (9.0%), the alteration minerals are a high medium in abundance (41.2%), as are the iron minerals (27.4%). Amygdules and vesicles are medium in abundance (10.9%). Plagioclase has an average size range (.144-.640 mm.), the pyroxene range is medium (.240-.800 mm.) on the large end of the size scale, and the size range of the amygdules and vesicles is just below average (.528-2.000 mm.) and is in about the middle of the size scale. Sample C-l9-1200-66 A medium brownish gray, diabasic, porphyritic, amygda- loidal, vesicular, ophitic basalt. The andesine plagioclase is medium low in content (19.4%), but there are many very small plagioclase microlites not identified that may or may not be andesitic in composition. The ferromagnesian mineral content is also low (4.2%), the alteration mineral content is also low (22.0%), and the iron minerals are high in abundance (30.4%), while the content of amygdules and vesicles is very high (26.4%). The plagioclase grain size 54 is about average (.128-.832 mm.). Thepyroxene grain size range is one of the largest studied (.016-.288 mm.) and appears to cover about the lower two-thirds of the size scale. Amygdules and vesicles have an average size range (.528-3.120 mm.) in the middle of the size scale. Sample C-20-llOO-66 A light brown, diabasic, porphyritic, ophitic, amygda- loidal basalt. The plagioclase grains are hard to examine and appear to cover a wide range of middle labradorite and just into the andesine range, they are high in abundance in this sample (33.3%). The ferromagnesian mineral content is upper medium (22.6%), the alteration mineral content is low (19.5%), the iron minerals' is medium (17.4%), and the content of amygdules and vesicles is very low (1.5%). The size range of the plagioclase grains is relatively large (.096-1.216 mm.). The pyroxene size range is medium (.l44-.640 mm.), within the upper half of the scale. Amygdules and vesicles have a short size range (.320-.912 mm.) in the lower part of the size scale. Sample C-21-1000-66 A light brownish gray, diabasic, porphyritic, amygda- loidal, vesicular, cphitic basalt. Much of the medium high content of plagioclase (25.0%) is highly altered, while some feldspar grains in a veinlet are very fresh. The plagio- clase laths with identifiable extinction fall into the 55 andesine range. The ferromagnesian mineral content is very low (5.2%), the alteration minerals are medium in abundance (34.6%), as are the iron minerals (23.2%), and the amygdules and vesicles are on the low side of being medium in abun- dance (8.2%). The size range of the plagioclase grains is a little larger than average (.096-.768 mm.), while the size range of the amygdules and vesicles is very large (.272- 3.680 mm.), starting low on the size scale. The one pyroxene grain measured is .640 x .112 mm. in size. Sample C-22-900-66 A light greenish gray, diabasic, amygdaloidal, por- phyritic, Ophitic basalt. The feldspar grains vary from a few very clear laths without albite twinning to numerous small, altered microlites. The identifiable plagioclase grains are predominately scattered throughout the middle of the labradorite range with a few grains appearing to be in the andesine range. The total plagioclase content is medium low (20.2%). Ferromagnesian mineral grains are upper medium in abundance (23.6%) while the alteration minerals rank about medium (35.2%) as do the iron minerals (17.8%). Amygdules and vesicles are very low in abundance (1.2%) and still rank low when the veinlets (4.2%) are added to the total (5.4%). The size range of the plagioclase grains is slightly larger than average (.096-.704 mm.), the pyroxene range is a large medium (.048-.800 mm.) in the middle of the scale, while the range for the amygdules and vesicles 56 is medium (.288-l.216 mm.) and near the small and of the scale. Sample C-23-800-66 A medium brownish gray, diabasic, porphyritic, amygda- loidal, Ophitic basalt. The content of plagioclase.grains is medium (22.8%) and they are predominately in the labra- dorite range. Ferromagnesian mineral grains are upper medium in abundance (24.6%) while the alteration minerals (26.4%) and the iron minerals (23.4%) are both medium.» The amygdule and vesicle content is very low (0.6%). Plagio- clase grains have a size range a little larger than average (.096-.832 mm.), Pyroxene grains have a medium size range (.128-.560 mm.) in the upper half of their size scale, and the amydgules and vesicles have a very short range of sizes (.800-1.280 mm.) in about the middle of the size scale. Sample C-24-700-66 A medium-brownish gray, diabasic, porphyritic, amygda- loidal, ophitic basalt. The plagioclase content is medium high (27.6%) and is in the andesine range. The larger feldspar grains are cloudy with hematite and there is a small number (8.4%) of them that do not appear to be plagio- clase. Ferromagnesian minerals are very low in content (1.2%), the alteration minerals are a low medium (24.4%), and. the iron minerals are high in abundance (28.6%) as are the amygdules and vesicles (17.8%). Plagioclase grain sizes 57 are in the average range (.128-.832 mm.), the one pyroxene grain that was measured is medium in size (.176-.O96 mm.), and the size range of the amygdules and vesicles is the second largest measured (.240-6.560 mm.) and covers the whole size scale. Sample C-25-600-66 A light brownish gray, diabasic, porphyritic, amygda- loidal, ophitic basalt. The andesine plagioclase content is medium low (18.4%), many of the grains are clouded with a red powder, probably hematite. There is also a small con- tent of feldspar grains (9.8%) that do not appear to be plagioclase, but more.1ike1y the K-feldspar mentioned in the literature. Ferromagnesian minerals are nearly absent (0.6%), the content of alteration minerals is very high (46.7%), while the iron minerals are medium in content (20.5%) as are the amygdules and vesicles (11.6%). Plagio- clase grain sizes vary over quite a large range (.096-992 mm.) while the range for the pyroxene grains is low (.096-.224 mm.) and near the middle of their scale, the range for amygdules and vesicles is large (.288-2.656 mm.) and in the low part of the scale. Sample C-26-500-66 A light pale brown, diabasic, porphyritic, amygda- loidal basalt. The labradorite plagioclase is medium high in abundance (28.7%), the ferromagnesian content is medium 58 (21.6%), the alteration mineral content is a low medium (24.1%), the iron minerals are medium (20.3%), and the amygdules and vesicles are very low in abundance (2.4%). The size range of the plagioclase grains is about average (.112-.560 mm.), that of the pyroxenes is medium (.064- .320 mm.) and slightly below the middle of the scale, and the range of sizes of the amygdules and vesicles is small (.800-1.520 mm.) and is located in about the middle of their scale. Sample C-27-400-66 A light brownish gray, diabasic, porphyritic, amygda- loidal basalt. The plagioclase is andesine and the grains are medium in abundance (22.6%). The ferromagnesian mineral content is very low (6.4%), that of the alteration minerals is a high medium (40.1%), the iron minerals are medium (19.7%), and the amygdules and vesicles are low (5.9%) in abundance. The plagioclase size range is the largest of the samples studied (.064-1.680 mm.) and covers the whole size scale, the range of the pyroxene grain sizes is medium (.032-.336 mm.) and is in the low to medium section of the size scale while amygdules and vesicles have an average size range (.272-1.640 mm.) in the lower part of the size scale. Sample C-28-300-66 A pale gray-red, diabasic, porphyritic, ophitic, amygdaloidal basalt. The labradorite plagioclase content 59 is medium high (26.7%), the ferromagnesian mineral content is medium (21.1%), the alteration mineral content is low (20.5%), iron minerals are medium in abundance (19.3%), and the amygdules and vesicles are low (2.1%), even when the low percentage of veinlets (1.6%) is added to them (3.7%). The plagioclase grain size range is average (.128-.704 mm.) in about the middle of the scale, the pyroxene range is medium (.048-.320 mm.), toward the lower end of the scale, and the size of the one amygdule measured is very large (5.390 X 1.952 mm.). Sample c-29-2oo-66 A pale yellowish brown, porphyritic, amygdaloidal basalt. The plagioclase is andesine and it is medium low in abundance (15.0%). Ferromagnesian minerals are nearly absent (1.0%). The content of alteration minerals is medium (34.0%), the iron minerals are very low in abundance (7.2%), and the questionable amygdule and vesicle content is the highest encountered in the study (32.8%). The size range of the plagioclase grains is relatively large (.080-1.184 mm.) while the amygdule and vesicle size range is medium (.976-2.832 mm.) near the center of the size scale, but actually more than half of the hand sample is one very large amygdule too large to measure completely. Sample C-30-100-66 A light pale brown, amygdaloidal, ophitic, porphyritic 60 basalt. The andesine plagioclase content is medium low (17.6%), many of the grains are altered. A fairly low content of ferromagnesian minerals is present (10.0%), the alteration minerals represent a low medium abundance (25.0%), and the iron minerals show a high medium content (26.8%). The amygdule and vesicle content is medium (12.4%). The size range of the plagioclase grains is quite large (.128-1.414 mm.), that of the pyroxene grains is medium (.224-1.312 mm.) near the upper end of the size scale, and the range of the amygdules and vesicles is medium (.832-3.200 mm.) and near the small and of the size scale. Sample C-3l-0-66 A pale red, diabasic, ophitic, amygdaloidal, vesicular basalt. The andesine plagioclase content is medium (23.0%) with a small amount of finely divided material present (5.1%) that may also be partially plagioclase. The ferro- magnesian mineral content is fairly low (8.7%) and the alteration mineral content is low (22.4%), while the iron minerals have a high medium content (27.3%). The amygdules and vesicles are quite low in abundance (6.4%). The plagio- clase grain size range is about average (.096-.528 mm.) in about the lower middle of the size scale. Pyroxene grains have a medium size range (.160-1.600 mm.) at the large end of the size scale and amygdules and vesicles have a medium size range (.272-1.040 mm.) at the small and of the size scale. APPENDIX B Figure Figure Figure Figure Figure 18. 19. 20. 21. 22. 61 Percent plagioclase vs. sample number Percent pyroxene vs. sample number Percent olivine vs. sample number Percent leucoxene vs. sample number Percent iddingsite vs. sample number 62 40J Percent H'lo OO 1 J /. \/. b.) O L \ 20‘ ”1 "\/"'/\-\,,.\. \/\/ \/\/ \,,/\/ \f“ 0. Percent Figure 19 20 10 .1. \ 0 0.0—. '\e—e—o—.—./.‘.‘O/ \./.\ Percent e— e—o- e/ /.\‘-O/. \/.\ Figure 20 20 O 10 /\ / o . . e 0 .’.~./° \Ko/O\e-—'/ \°"/.-— \e/ \.’.\O~./.\'*O’.\e/ \ ... Percent Figure 21 20 10 0 Percent In . ./' . e ' 0" o \./\./ \.-./ \'/.\'\,/.’ \./ \.’.\./._.\. /O‘./'\./ N. Figure 22 I V I ‘ "U‘rrt'jrjjii'VV'Ur'I'r'fi l 1 5 10 15 20 25 30 Sample Number Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. 61 Percent plagioclase vs. sample number Percent pyroxene vs. sample number Percent olivine vs. sample number Percent leucoxene vs. sample number Percent iddingsite vs. sample number 62 404 \/,\N 0- .\./’ . \, ° , . . :0‘ \' \'\/ \/./\.\-’/ \./ \'/\ ,-/. 1,1 \/.\, 0.. Percent Figure 18 BoJ 20‘ . \,\. . .1, .- . 10 L'/.\ /°‘°/\\,.\, \/.\/ \’\-/\/ \H/\/\/" o. e Percent Figure 19 20 10 “o \ 0 .‘h" '\e—o-e—e—e/.""/.\o/.\ Percent ....-.-./'/.\.-./'\-/.\._.-. Figure 20 “'3 . § 10 , ./\, I: O ./’—o/ \e/.\e-"/ \"’/.'.\o/ \.’.\e-,/.\O_./'\./ \ h. ’. e . /' . . e . e 0 e/ \./ \./0 \.__./ \./.\.\./e’ \./ \.’.\./e—.\.‘./O‘./ \./ Figure 22 fiUU'U'I'r'V'T'UIUU 'V'j'vt'I'I 1 5 10 15 20 25 30 Sample Number Figure 23. Figure 24. Figure 25. Figure 26. 63 Percent hematite vs. sample number Percent sericite-saussurite vs. sample number Percent pumpellyite vs. sample number Percent chlorite vs. sample number 40d 30* 20- 104 '\. Percent on Figure 23 Figure 24 a” 0203 £101 ' 30- l Eg20 0 101 s. G) Di 0.4L Figure 26 \,\/ \ / \/\/ 64 Sample Number ‘Tfjj' 15 V V I 20 /\ /’\. /\-\ rt V V 1 U V 1 I ._.\\/.... WP" 30 65 Figure 27. Percent epidote vs. sample number Figure 28. Percent calcite vs. sample number Figure 29. Percent pyroxene and olivine vs. sample number Figure 30. Percent hematite and iddingsite vs. sample number 66 w 9 5’ Percent Hm ?’ i ............. / \/\ ......... , ..... ............ O Figure 27 1'3 3 101 g 0 0—0/\ ooooooo / \o/\ ooooo /.\0/.\o—o/.\o/.\O—-/.\U —————————— Figure 28 4.3 30- .N . § 20‘ .\..-o \. . . o g 104 0/. \ \ \o \ .‘o 0.i b \. .\./'\. \. ' 0‘. . o/ Figure 29 ”0+ . -n 30q ° . g /\ /’ ' ./\ . /\ rd 2 20:1 .\ o\ .-./h..- \ o’,\/\/ ./ \O/ 0—0~o-o / o o ./ ./ c \ m 10-4 ,/ . 0L Figure 30 it IV; I I I IlerI '1'5I I I12'OU‘fVé5'TVUfi' Sample Number Figure 31. Figure 32. Figure 33. 67 Percent sericite-saussurite and pumpellyite vs. sample number Percent sericite-saussurite, chlorite, and pumpellyite vs. sample number Percent sericite-saussurite, chlorite, pumpellyite, calcite, and epidote vs. sample number Percent Percent Percent 20‘ 3°“ «.\/ \\./"'/\,/\,/"'//\.\/\/\/\/\\ :: / \/\/\\ /\ , /k'/\\,/\\"/\' y'uvifi'I1711IIIleIIIII 5' ' ' 10 15 20 25 3° Sample Number 69 Figure 3#. Percent plagioclase, pumpellyite, sericite- saussurite and epidote (dashed line includes K-feldspars vs. sample number Figure 35. Percent olivine, pyroxene, iddingsite, and chlorite vs. sample number 70 70- psooaom Figure 3h 50- o\\ \ . .../e \.V. \o \ o\\|\\l|wo /o nu Aw mw I”. 3 1 unoohom Figure 35 Sample Number 71 Figure 36. Percent ratio of plagioclase, pumpellyite, sericite-saussurite and epidote (dashed line includes K-feldspars to olivine, pyroxene, iddingsite, and chlorite vs. sample number Figure 37. Percent cOpper (visual estimation) vs. sample number 15‘ Percent ...I '9 15- 10¢ Percent 54 OJb o—o—o . Figure 37 ‘r‘ 72 T1ful1I1I '1 ’. C . 'VVII I'V'I l 1 u 10 15 20 25 30 Sample Number 73 Figure 38. Percent amygdules, vesicles, and veinlets vs. sample number 7a no- 30. ' 20. . - . lo- /\ /'\-/\ /\/\ /\ /\ \. . 0 /. . . \, OJ. '/ ./'\./ ._./o O ' ./ \.\. \./o\. Figure 38 | r I I l I I I I T I r r I 1 fit I I I I I r1 l I ILI I Ii 1 5 10 15 20 25 30 Sample Number APPENDIX C £210 ’60 ZZBNQHflQWWUOw> F303 75 Out Of In Phase Phase Plagioclase Pyroxene Olivine Leucoxene Iddingsite Hematite Sericite-Saussurite Pumpellyite Chlorite Pyroxene and Olivine Hematite and Iddingsite Sericite-Saussurite and Pumpellyite Seribite-Saussurite, Chlorite, and Pumpellyite Sericite-Saussurite, Chlorite, Pumpellyite, Calcite, and Epidote Amygdules, vesicles, and veinlets Plagioclase, Pumpellyite, Sericite-Saussurite and Epidote Olivine, Pyroxene, Iddingsite, and Chlorite Ratio of Plagioclase, Pumpellyite, Sericite- Saussurite and Epidote to Olivine, Pyroxene, Iddingsite and Chlorite Calcite Epidote Legend for Figure 39 76 _ . _“ ;;_.:_ : __ :2“ .____ _:_ :: I E 1'0 1'5 50 95 ‘90 __ _ . g :_:_ L __ ______ w ___: __ _:_ Z _ _ _ _ _ ._____ _:_ m: T_._ __.__"____ Sample Number 0 25 Comparison of the mineral percentage vs. sample number charts m 0 Figure 39. 44D4d1um+_<fih4.i.qdqmy ..-.Dmdfim11_rmd..p_.u:mw .qqm.qfium-qdbfiaqmi:-T BC F J N B BC FG JK N0 3 BC FG K .A .5 Ti n” Au .A an Ti nu .A an Thu Mm" .mm 77 15 1015202530 __J *— Sample Number [-510 15 20 25 30 H. M 3:13 ____._: __ t _ u:__ ‘ _ ___ ____ a ~_ __ _ _. _ _n __ ___” :_ 3.: ___ T“. ___ . __ ______:_ ;__ 2. _ _ c m qnwm.finwnm:vm.m41n.unm:hum. Inwm..nwurqqunfi.qnwhjhuml 21:... .Mb nwi .Ld Mwu 0%“ .LB “My Thu MW" “fin (Figure 39 con't) A d ___-...... ———— ___..— B - _ .h_“___ 04 — — — — — E1? ”2 : ___: ___ __ __ GH-q 1“— "_ _‘_’_.‘_'. —. - " + -——- -— -— -—- I d _ — ... _ ‘1sz _ _ _ .... no _— NOP; _ - —- "'— Q d - —- _ J ___ _— RS ‘ _ _ ___ _ T- —— — ... _ A - __._____.__H__._. B 4 ____ ____.____ ch -- —-—— .— E Ill ___ —— —- _— .J —_—_ ___. _ — PG d —— _. h —-n—-_-—————_—_-b I H} _* — JK -== -.__._..__ __ ____. cw .. L“ __ _ __ _ M .- NO 1 _ __ ___ — Pq —— -— QR : __: _:_"—__ _ S u — __ —h _— T- _ ___. .. AB - “— —_.._ __ __i _k c q — _— _ — _ — D“ __ _ ___. EF - —— ———— -— ———— _ 91. —— -—-—- :'_-:—:- H- —- IJ : KL: o n o N 2 .20- 6) a. E o 10! <::> & 0 DH 0 fl (3 ' \\L/ \l// T I ’1 O l 20 30 #0 50 60 Percent Epidote and chlorite Comparison of percent pyroxene vs. percent epidote and chlorite no- 09 ? Percent pyroxene and olivine N ééggf Percent plagioclase Comparison of percent pyroxene and olivine vs. percent plagioclase 82 um 13 a. 4.) 0d 43m 33° fig £14 4.) s 0 $4 0 D4 I l T j 30 #0 50 60 Percent iddingsite and chlorite Figure ##. Comparison of percent pyroxene and olivine vs. percent iddingsite and chlorite no- 20- 10- Percent chlorite <::> ‘i'K“! I l l T 1 fl 0 lO ‘2U/NV730 #0 5O 60 Percent hematite and iddingsite Figure #5. Comparison of percent chlorite vs. percent hematite and iddingsite Figure #6. Figure #7. 33 uo~ Percent chlorite I I I #0 50 6O Percent olivine and pyroxene Comparison of percent chlorite vs. percent olivine and pyroxene #0 1 30“ 0 .p I!" 54 .3 20 - S O 43 i. 8 g a 10 ‘ vA 0 01 0 T y u o #0 50 60 Percent amygdules, vesicles and veinlets Comparison of percent chlorite vs; percent amygdules, vesicles and veinlets 8# “Q 3 o “0- «4 m 0 bu J3 sg 3°“ '50: hd 20- 38 ‘5 g 10- t 04 o I o 10 Percent sericite-saussurite, chlorite, and pumpellyite Figure #8. Comparison of percent amygdules, vesicles, and veinlets vs. percent sericite-saussurite, chlorite and pumpellyite m 3 o “'0“ .4 0) O P m .2 O m H 30" 0 F: H H .5 2 :30? 2°- ‘3 g 10« $1 0 m ‘\ G ' \‘ ‘ I o 10 20 0 #b 55 66 Percent sericite-saussurite, chlorite, pumpellyite, calcite, & epidote Figure #9. Comparison of percent amygdules, vesicles and veinlets vs. percent sericite-saussurite, chlorite, pumpellyite, calcite, and epidote APPENDIX D 85 1001 90- so. 70- 60« 50' no- 30‘ 20- 10- 0—0 0—0 0 Percent anorthite I \. ; 4—1 A 'r'Ul'VV'ij'IU‘U'I'rVTUVYVIVI'V 1 5 10 15 20 25 30 Sample Number Figure 50. Percent anorthite vs. sample number 86 10.— q q q 1 loo—z :3 db 4) Q) q E H a-I .... H H E: _ 0.1-1 4. 4 d J .01 TlllIIFTTIIlllTllllllrillelll' 1 5 10 15 20 25 30 Sample Number Figure 51. Size range of plagioclase grains vs. sample numbers 87 10. I Llllll l L 1 1 IIJIJ Millimeter 1 ‘ '01 IIITIII11IIIIIIIIIILillll1i11rl l .5 10 15 2 25 30 Sample Number Figure 52. Size range of pyroxene grains vs. sample number 88 100— : uni 1.0—: ' fll A -l o - 4.) a) I: E H H - r: .... z - 001—: ~01 ll lllIlll IIII IIII llllll III III r1 1 5 10 15 20 25 30 Sample Number Figure 53. Size range of amygdules and vesicles vs. sample number 89 :: '\/ ..... \/\/ Hand samples :1 I B n A J e—o O—o #— Figure 5#. Grouping of hand samples according to general color, texture, etc. vs. sample number 5GI7/1- ' ‘ 5016/1- / \ 5Y6/1W 0 . 5YB-Y6/14 \\ . 5m 5/1- . . . . / . .-. sums/1. . / V \. /\ . \. . 5YB6/2? \\ // \f/ . 10YB6/2- //\\ 5136/24 . 535/2‘ 1035/24 . Color Figure 55. Bock-color chart number vs. sample number lrtroIFU'UT‘TIIUTT'IV'I'VIVI" 1 5 10 15 20 25 30 Sample Number 90 0 10 value . 5 \R chroma 5 . 10 CI I I 1 l l l f l l 10 5 0 '1' GY hue color number of samples SGY7/1 3 SGY6/l ; # total Figure 56. G! color value plots 91 0 10 value V/ ‘\ chroma 5 O c O r l | 103 I 5 l I I r’ 0 '1? hue color number of samples 586/2 1 5135/2 3 1035/2 .1. 5 total Figure 57. B color value plots 92 color number of samples 5YR6/1 7 SYRS/l 7 5YR6/2 # lOYR6/2 _1 19 total Figure 58. YR color value plots "7:1;(((maumaimmvr