Conadion MinerologistVol.28, pp. 161-169 (1990)

SOLID PYROBITUMEN IN VEINS. PANEL MINE, ELLIOT LAKE DISTRICT. ONTARIO

JEFFERY STEYENSON, JOSEPH MANCUSO AND JOSEPH FRIZADO

Department of Ceologlt, Bowling Green Stote University, Bowling Green, Ohio 43403' U,S.A.

PAUL TRUSKOSKIPanel mine, Rio Algom Limited, Elliot Loke, Ontoio PsA 2K1

WILLIAM KNELLERDepartrnent of Geologlt, University of Toledo, Toledo, Ohio 43606, U.S.A.

ABSTRACT

Globular blebs of solid pyrobitumen (lhucholite of olderreports) are found in veins exposed in open stopes and driftsin the Panel miue in the Elliot Lake uranium district,Ontario. The veins fill fractures n the 2.2-2.4 GaMatinenda Formation. The blebs are s-all (l-10 mm) andvary in shape from round to discoid, twisted or elongate.Their surfaces are shiny and permeated with vesicles. Theblebs are eomposed predominantly of carbon with a H/Cratio of 0.57, a reflectivity (R-) of 0.9V0, and a 6l3C valueof -330/oo @DB). Pyrobitumen formed early in the veins.The paragenetic sequenc€ ofninerals and pyrobitumen is:quartz, pyrite I, pyrobitumen, sepiolite, pyrite II, pyrrho-tite and galena, and finally calcite. The pyrobitumen blebsin the Panel mine are the result of natural migration andmaturation of Precambrian petroleum. Pefoleum migratedinto fractures, and, with time and increased temperature,polymerized into tarry masses that matured inlo blebs ofsolid pyrobitumen.

Keywords: pyrobitumen, kerogen, thucholite, Elliot Lakedistrict, Ontario, Huronian Supergroup, Precambrianpetroleum, organic geochemistry.

SoMNaerns

Des globules de pyrobitume solide 0a "thucolite" desrapports antdrieurs) ont 6te d6couverts dans de fissuresexpos€es le long des galeries de la mine Panel, daas le campminier uraniffre de Elliot Lake, en Ontario. Les fissuresse trouvent dans la Formation de Matinenda, dont l'6geest fix6. d2.2-2.4 Ga. Les globules sont petits (l-10 rqm)'ronds d discoides, et tordus ou allong6s. Leur surface pos-slde un 6clat brillant et rdv&le un r6seau de cavi16s. Ils con-tiennent surtout du carbone; le rapport H/C a une valeurde 0.57, la rdflectivit6 (R.), 0.990, et 613C, -330l0o @DB).Le pyrobitume s'est form6 d un stade precoce dans les fis-sures. La s6quence parag6ndtique de l'associationmin6raux-pyrobitume serait: quartz, pyrite I, pyrobitume,s6piolite, pyrite II, pynhotite et galbne, et enfin calcite. Leselobules de la mine Panel sont le rdsultat de la migrationnaturelle et de la maturation d'un p6trole pr€cambrien. Lep6trole a d'abord migr6 dans les fissures; avec le temps etune temperature plus 6levde, il est devenu polym6ris6 enmasses goudronneuses qui ont 6volu6 en globules de pyro-bitume solide.

(Iraduit par la R6daction)

Mots-cl4s: pyrobitume, kdrogdne, "thucolite", district deElliot Lake, Ontario, Supergroupe Huronien, pdtroleprdcambrien, geochimie organique.

INTRoDUcTIoN

In the Panel mine of the Elliot Lake uranium dis-trict, Ontario, globular carbonaceous blebs occur inveins that cut the Matinenda Formation. Kaiman &Horwood (1970 described similar material from thenearby Milliken miue and concluded that the carbo-naceous blebs, termed "thucholite", were formedby the agglomeration aud polymerization of carbonparticles from the exhaust of diesel mining equip-ment. We propose that the carbonaceous blebs(pyrobitumen) in veins in the Panel mine resultedfrom natural migration and maturation of petroleumderived from Proterozoic kerogen.

Thucholite, an acronym for Th, U, C, H, and O@llsworth 1928), has been used in reference to car-bonaceous material in the radioactive conglomeratesof the Elliot Lake district. Pyrobitumen, as definedby Hunt (1979), is black to dark brown bitumen tlatis infusible and <2t/o soluble in carbon disulfide.The carbonaceous blebs in the Panel mine containless than 0.5 ppm of thorium and uranium and are<290 soluble in carbon disulfide; therefore, the termpyrobitumen is preferred. Willingham et al. (1985)described the occurrence of stratiform and dispersedkerogens (insoluble organic solid that does notmigrate following sedimentation) in the MatinendaFormation from the Stanleigh and Denison mines.They suggested that dispersed globulax particles werederived from this kerogen.

Blebs of similax morphology and occurrence havebeen reported from veins in the Cambrian Bon-neterre Formation from the Magmont mins ea ffusViburnum Trend, Missouri (Marikos el a/. l98O andthe Ordovician Trenton Formation in WyandotCounty, Ohio (Haefner et al. 1988). Both are consi-dered to have been formed from locally derived oilthat was polymerized in fractures.

l 6 l

t62 THE CANADIAN MINERALOGIST

GEoLoGIcAL SSTTINc

The Huronian Supergroup consists of asouthward-thickening wedge of coarse clastic sedi-ments with local basal volcanic units and minorchemical sediments (Colvine 1981, Mossman & Har-ron 1984, Robinson & Spooner 1984). The lowermostgroup of the Huronian Supergroup is the Elliot LakeGroup, which rests disconformably on Archeangneisses and gxeenstones @rarey 1977, Frulick &Miall 1981, Young 1983). The Elliot Lake Group hasbeen described by Card et al, (1977) as an interfin-gering sequence of feldspathic quartzites and con-glomerates of various types, that include the ura-niferous quartz pebble conglomerate (MatinendaFormation), and a westward-thickening wedge of silt-stones, argillites and greywackes (McKim Forma-tion). The overlying Hough Lake, Quirke Lake, andCobalt Groups represent major sedimentarysequenses consisting of conglomerates, sandstones,siltstones, and saxbonate formations (Pienaar 1963).

The Matinenda Formation is subdivided into twolithofacies: lower coarse sandstones with interbed-ded conglomerates and upper fine- to coarse-grained,poorly sorted subarkoses, lithic arkoses, and lithicsubarkosic wackes @ienaar 1963). The uraniferousconglomerates are found in the lower sandstonelithofacie. Conglomerate deposition appears to havebeen controlled by basement topography (Fralick &Miall 1981, Young 1983). The depositional modelpostulated for t}te Matinenda Formation, interpretedfrom sedimentary structures such as cross bedding,scour and fill, mud drapes, and imbrication, is abraided stream environment (Fralick & Midl 1981,Pienaar 1963). Intruded into the rocks of the Huro-nian Supergroup are swarrns of Nipissing Diabasesills and dikes @otter 1987,Frarey 1977).

The age of tle Elliot Lake Group is2.2to2.4Ga.This estimate falls between the ages of 2.1 I t 0.08for the Nipissing Diabase (Van Schmus 1965, Fair-burn et al. 1969), and2.333!$.ffi! Ga (Frarey et ol.1982) and 2.38818:ffi9 Ga (Iftoeh et al. 1984) for theCreighton and Murray granites, which intrude theElliot Lake Group in the Sudbury area.

MINERAL EARLY LATE

l s m . --?4s6..-

Frc. 1. Paragenetic sequence of minerals and pyrobitumenin fractures in the Matinenda Formation, Panel mine.

Folding and metamorphism related to thePenokean Orogeny followed deposition of the Huro-nian Supergroup and intrusion of the Nipissing Dia-base. Van Schmus (1965) concluded that thePenokean Orogeny reached its peak activity in theElliot Lake region between 1.7 and 1.8 Ga. Meta-morphic grade of the Hu'ronian Supergroup rockslangss from subgreenschist in the Elliot Lake areato amphibolite south of Espanola (Robertson 1978,Card 1978, Cardet al. 1977). Robinson & Spooner(1984) characterized the grade of metamorphism inthe Elliot Lake area as "negligible".

Frc. 2. Scanning electron photomicrograph of pyrobitu-men (P) on quartz (Q). Scale i1 millims1s13.

QuartzPyrite

Pyrobitumen

Sspiolite

Pynhotite

Galena

Calcite

Fro. 3. Pyrobitumen @) on frst-generation pyrite (Pl).Scale in millimeters.

PYROBITUMEN IN VEINS, ELLIOT LAKE, ONTARIO 163

Fro. 6. Depression in second-generation pyrite (P2) linedwith sepiolite (S). Pyrobitumen bleb @) has been par-tially removed. Scale in millimeters.

FIc. 4. Pyrobitumen blebs encased in "cocoons" of sepi-olite. Specimen is 5 cm in length.

Frc. 5. Scanning electron photomicrograph of pyrobitu-men (P) partialy encased in sepiolite (S).

PynonTTuMeN IN THE ParvBL MTI'IE

Pyrobitumen blebs in the Panel mine are foundin fractures, vrrgs, and veins in the Matinenda For-mation. Numerous generations of fractures cut theMatinenda Formation. Frasfure zones range in widthfrom <2 cm to 45 cm. Pyrobitumen is found in wgsand other openings within the fractures, but com-prises <190 of the material in the fractures. Frac-tures that contain pyrobitumen were not observedcrossing diabase dykes. The fractures strike from N45" E to N 30" W and dip nearly vertically. Rocks

Frc. ?. Blebs of pyrobitumen illustrating round' elongate'twisted and other forms. Scale in millimeters.

along some fractures are chloritized' whereas rocksadjacent to other fractures are unaltered. Potter(1987) concluded that chloritization of the wallrockspostdated the emplacement of Nipissing Diabase butpredated Penokean metamorPhism.

PenacsNErIc SeQUENcn

Thin and polished section petrography and scan-ning electron microscopy wit[ an energy-dispersionarnlyzer were used to describe the morphology ofthe pyrobitumen and to interpret the parageneticsequence. The paragenetic sequence ofminerals andpyrobitumen in the fiactures is: quartz, pyrite I,pyrobitumen, sepiolite, pyrite II, pyrrhotite andgalena, and finally calcite (Fig. l).

Quartz, the first mineral to crystallize in the frac-tures and vugs, lines vein walls in contact with theMatinenda Formation. Euhedral to subhedral crys-

W.}ff,ill.}j.{

t64 THE CANADIAN MINERALOGIST

tals range from < I mm to I cm in length. Follow-ing the precipitation of quartz, a first generation ofpyrite was deposited. Pyrite I occtus as etched androunded cub€s (l-5 mm across) coating euhedral andsubhedral crystals of quartz.

Petroleum was introduced into the fractures afterpyrite I. Tarry masses, which were free to move,attached themselves to the surfaces of quartz andfirst-generation pyrite (Figs. 2, 3). Subsequently, thetarry blebs polymerized into solid pyrobitumen byoutgassing, water-washing, and thermal cracking.

Sepiolite formed after the initial hardening of thepetroleum. It occurs as fibrous and lath-shaped crys-tals <2 mm in leneth. The blebs of pyrobitumen are,in places, encased in "cocoons" of sepiolite (Figs.4, 5). The crystals were identified as sepiolite byenergy-dispersion and X-ray-diffraction analyses.

Subsequent to sepiolite crystallization, second-generation pyrite began to crystallize. It occurs ascubes that range in size from (l mm to 1.5 cmacross, with clean faces and sharp edges. Crystalsof pyrite II form a yellow crust on the sepiolite fibers.Large cubes of pyrite (1.5 cm) in places enclosepyrobitumen blebs. Where pyrobitumen has beenremoved from large pyrite crystals, imprints of sepiolite and pyrobitumen remain (Fig. 6).

Pyrrhotite and galena depositio"n occurred u/ithpyrite II. The limited number of samples contain-ing pyrrhotite and galena make interpretation of theparagenetic relationships somewhat speculative;however, it appears that pyrrhotite, galena, andpyrite II were penecontemporaneous. Galena occursas cubes ( I cm asross, and pynhotite occurs assmall hexagonal crystals < 5 mm in length. Blebs ofpyrobitumen are partly encased in galena and pyr-rhotite.

TABLB 1. COMPC'SITION OF PYROBMJMENAND BITT'MEN

CotmftlioB(p!m)

Paml Tletuon B@temI\,trel Fmatiool Fmado!2

Calcite was tlte last mineral to crystallize in theveins. It occurs as clear, euhedral crystals up to 2cm in length that surround and enclose quartz,pyrobitumen, sepiolite and pyrite II.

ANALYSES oF PYRoBITUMEN

Fyrobitumen forms small black blebs up to l0 mmin diameter. The shapes vary widely from round todiscoid, kidney to saddle, twisted or elongate (Fig.7). The surface of the pyrobitumen is shiny and per-meated with vesicles. The blebs are brittle and dis-play a conchoidal fracture where broken. Thepyrobitumen is amorphous to X rays, indicating thatit does not have a well-defined crystalline structureand is, therefore, not graphite. Multiple samples ofpyrobitumen and associated minerals were collectedfrom nine vein locations in the mine, includingseveral newly opened stopes that had not been previ-ously exposed to mining equipment exhaust.

Elemental analysis

Blebs of pyrobitumen were analyzed commerciallyby LeDoux & Company using semiquantitative sparkmass spectroscopy (Table l). The results of the ana-lyses show the blebs to contain <0.5 ppb uraniumand thorium. Sulfur is a major constituent (> 1000ppm), and iron is present at a concentration of 300ppm. Nickel and sodium are each 20 ppm, and cal-cium is 10 ppm. Other elements are 5 ppm or less.

Bitumen blebs from veins in the Ordovician Tren-ton Limestone also were analyzed by spark massspectroscopy for comparison. The uranium concen-tration is 2 ppm, and the thorium concentratipn is<0.5 ppm. Sulfur, iron, and calcium are major com-ponents of the bitumen (> 1000 ppm). The blebs alsocontain appreciable concentrations of magnesium,potassium, nickel and sodium (Iable l). Pyrite, mar-casite, calcite, dolomite and glpsum were identifiedin the veins with bitumen by Haefner et al. (1988)and most likely are present as inclusions in the bitu-men. Comparison of the Trenton data to those fromthe Panel mine indicates, in a broad sense, that sul-

Rdk@ aoc nc c(DB)

UTbM

CaMCI\toql

Pb7^sNaKsiAI

Sepleledi@

<0.5<0.5n

30010AIII5

Mm

I0.5

<0.5l5MM

1@50.6

M50

50t0

trd

!dnd

!d

2M24010030

tsn1m0

r5000Dd

trd

nd

nd

Pyrcbihfttr O.gt%PamlM@ I (MSD0.(2)

Csb@ Bl€h6MlitetrMie 2 u

Biffi ill ] m F n s

Pytobi@,Ge@lDeh'

-ft 0J7 79.8% AorPto

-U Ed 80.0% A@pb@

t.4r K.6%

-4 0J3 d

1. Spad( mass speafGcopy (LBDU & Compmy). 2. Emtsslonspectro3copy (Marlkos ot al, 1986). M - Gredor than 1000 ppm. A -Matrlx Inlertorsnco. nd - Not dotormln€d.

l. M!l@ a al. (l9BO. 1 Ktud & H@eod (lq'6l 3. MEil6 d 8L (l9BO4. grd(lYr9). nd-Nc dde.Etr€d

PYROBITUMEN IN YEINS, ELLIOT LAKE, ONTARIO

fur, iron, calcium, nickel, and sodium were enrichedin both envlonments. 85

Marikos et al. (1986) reported metals and sulfurin blebs of bitumen from the Cambrian BonueterreFormation in Missouri. They concluded that t}te highlevel of metals and sulfur in blebs of insoluble bitu-men probably indicates that the blebs were semiliquidwhen they encountered metal-containing solutions.A similar conclusion could be drawn for the enrich-ment of some of the metals and sulfur in tle pyrobit-umen from the Panel mine and the bitumen fromthe Trenton Limestone.

Hydrogen/carbon ratio

The hydrogen /carbon atomic ratio (H,/C) is a sen-sitive indicator of thermal alteration. DecreasingH,/C values result from polymerization and carbon-condensing reactions of thermal cracking processesand from dehydrogenation following deasphalting@ogers et al. 1974). AH/C value of less than 0.53is common for pyrobitumen (Hunt 1979). Thehydrogen-to-carbon ratio for pyrobitumen from thePanel mine is 0.57 (Table 2). Thermal alteration tothe catagenesis stage of petroleum maturation gener-ates H/C values from 0.5 to 1.5 (Tissot & Welte1984, Hayes et al.1983).

Carbon isotopes

The blebs of pyrobitumen from the Panel minehave 0r3C values averaging -32,61y@ (PDB) Man-cuso et al. 1989) (Iable 2). The greatest cause of frac-tionation of carbon isotopes is biological activity(Tissot & Welte 1984, Schopf 1983). Marine organ-isms that utilize carbon dioxide rather tlan HCO3-to build cellular material produce a significant defi-ciency in 6r3C tlrough photosynthesis (Hunt 1979,Schidlowski et ol. 1983). Hayes et a/. (1983) con-cluded that it is unlikely that an inorganic processwould produce such a large fractionation; therefore,a deficiency of 6r3C in the range of -25 to -35T*(PDB) hiehly suggests a photosynthetic origin. Also,the 6r3C value compares favorably with published613C values of Phanerozois reservoirs of naturalcarbon and, therefore, is consistent with our con-clusion that the blebs were formed by the matura-tion and destruction of petroleum after it migratedinto the fractures.

Scanning electron microscoPY

Kaiman & Horwood (1976) reported the presenceof low-level radiation in the outer margins of car-bonaceous blebs from the Milliken mins ssiqgautoradiography. Dot maps for U and Th in theblebs of pyrobitumen from the Panel mine macle withthe KEYEX energy-dispersion analyzer failed to re-

Wavenumbers ( cm "l )

Frc. 8. Infrared absorption spectra: A. pyrobitumen fromthe Panel mine, B. bitumen from the Ordovician Tren-ton Formation, and C. standard bitumen (LeDoux &ComPanY, 1986, Pers. co--.).

veal the presence of these elements. Back-scatterimagery also failed to show the presence of any 9le-ments of high atomic number in freshly brokenblebs.

Infrared absorption spectroscopy

Pyrobitumen from the Panel mine and bitumenfrom the Ordovician Trenton Limestone were ana-lyzed by infrared absorption spectrophotometry.'iheir absorption spectra are compared to a standardbitumen (FiC. 8). The infrared absorption spectrumfor the pyrobitumen from the Panel mine does notresembfe that of bitumen from the Trenton Lime-stone or the standard. LeDoux & Company (1986'written comm.) reported that spectra of the Panelmins pyrsfilumen do not se€m to indicate organicstructures but may be more consistent with a mix-ture of metal oxides and carbon.

165

80

75

70

65

E

F

i l s o

166 THE CANADIAN MINERALOGIST

Reflectance

Reflestance is one of the most useful measures ofmaturation and metamorphism of organic matter(Tissot & Welte 1984, Waples 1980, Hood et al.1975). h. is directly applicable to rhe study of ther-mal history of petroleum and provides a continuousnumerical scale that measures the process of matu-

FIG. 9. Bitumen (B) and dolomite crystals (D) from theOrdovician Trenton Limestone, Wyandot County,Ohio. Scale in millimelels.

Frc. 10. Scanning electron photomicrograph of bitumen@) on dolomite @) from the Ordovician Trenton Lime-stone, Wyandot County, Ohio.

ration and metamorphism. The maximum tempera-ture reached can be estimated provided the elapsedeffective heating trme is known @arker 1983). Theprincipal type of maceral used in reflectance studiesis vitrinite. Coaly material, however, which producesvitrinite, does not occur in Presambrian rocks; there-fore, pyrobitumen or kerogen is used in reflectancestudis on these older rocks (Duba & Williams-Jones1983). The relationships among reflectance, time,and temperature for pyrobitumen have not beenfirmly established, but are estimated to be compara-ble to those of vitrinite (Robert 1980).

Pyrobitumen from the Panel mine has a reflec-tance (RJ of 0.990 (Mancuso et al. 1989) (Iable 2),which suggests that the organic matter has not beensubjected to excessive thermal alteration. Compari-son of the reflectivity of pyrobitumen to the meta-morphic stages of petroleum based on vitrinite reflec-tance suggests that pyrobitumen from the Panel minefalls within the catagenesis stage (50 to 150"C) ofoil generation (Cordas & Kneller 1985, Tissot &Welte 1984, Hood et al. 1975). This inference con-curs with the conclusion of Willingham et al. (1985)concerning dispersed kerogen granules in two sam-ples from t}le Matinenda Formation at the Stanleighmine that have reflectivity values of I . I and 1.290 ,respectively.

DIscussIoN

The paragenetic relationship of pyrobitumen to theassociated minerals in the vugs and veins in the Panelmine indicates that the pyrobitumen formed earlyin the sequence. This finding is inconsistent with thesuggestion of Kaiman & Horwood (1976) that simi-lar carbonaceous blebs from the Milliken mineformed by agglomeration and polymerization of car-bon particles from the exhaust of diesel miningequipment.

The presence of sepiolite and the lack of graphiteconstrain the temperature conditions to which theblebs could have been subjected. Imai & Otsuka(1984) reported that sepiolite can crystallize underreducing conditions from low-temperature solutions(< 100'C) that are charged with magnesium, iron,and silica. Imai & Otsuka (1984) also stated thatabove 3@oC, sepiolite is not stable and recrystallizesto a talc-like mineral. X-ray-diffraction patternsshow that the blebs are not graphite. Carbon in theblebs would have crystallized into graphite above300oC. The reflectivity value of 0.970 (Rn) and thehydrogen-to-carbon ratio of 0.57 for the blebs ofpyrobitumen correspond to the catagenesis region ona van Krevelen diagram (Tissot & Welte 1984, Hayeset ql. 1983).

Low-grade thermal metamorphism accompanyingthe Penokean Orogeny (1.7-2.1 Ga; Van Schmus1965, Sims & Peterman 1983) is a possible thermal

PYROBITUMEN IN VEINS, ELLIOT LAKE, ONTARIO

drive to cau$e the cracking of kerogen and the for-mation of petroleum in the Matinenda or McKimFormation. Willingham et al. (1985) reported theoccurrence of stratiform and dispersed kerogens inthe Matinenda Formation, and concluded that thekerogens formed from mats of cyanobacteria thatwere affected by diagenetic and low-grade meta-morphic processes including partial remobilization.As the temperature rose into the catagenesis stagein these formations, kerogens cracked to formpetroleum, which migrated into fractures and sub-sequently became pyrobitumen. The 6r3C value of-32.260/00 @DB) for the blebs of pyrobitumenmatches values for petroleum from marine soruces(Hunt 1979).

Following migration into fractures in theMatinenda Formation, the petroleum was most likelyaltered to pyrobitumen by a combination of water-washing and thermal cracking. The process of water-washing would remove light hydrocarbons and turnthe oil into a more tarry form. As this tarry materialdetached from the wall, it formed spheroids thatfloated upward and were trapped in vuggy openingsin the fractures. The fluids from which later mineralswere precipitated may have been responsible for thewater-washing. Marikos et al. (1984 and Haefneret al. (1988) proposed similar models for blebs ofinsoluble carbon in the Cambrian Bonneterre For-mation from the Magmont Mining District in Mis-souri and the Trenton Formation in WyandotCounty, Ohio. Further examination of samples fromthese localities revealed morphologies and modes ofoccturence (Figs. 9,10, ll) similar to those found inthe Panel mine.

Alteration of the first-generation pyrite is furtherevidence for water-washing. Pyrite I crystals arerounded and etched by dissolution, whereas pyriteII crystals have sharp edges. The alteration of pyriteI appears to have occurred at about the same timeas petroleum was being introduced into the fracturesin the Matinenda Formation. Following the initialalteration by water-washing, the spheroids of tarunderwent thermal alteration. The vesicles thatpermeate the surface of the blebs (Fig. 12) indicatethat the tarry petroleum was in a semisolid state dur-ing outgassing.

CoNcLUSIoN

Data acquired from chemical and optical analyseslead to the conclusion that blebs of pyrobitumenfrom veins in the Matinenda Formation in the Panelmine resulted from the natural migration and matu-ration of Precambrian petroleum. The blebs ofpyrobitumen have solubilities, X-ray-diffraclion pat-terns, infrared absorption sp€stra, reflectivity values,hydrogen/carbon values, d13C values, and morphol-

Frc. ll, Scanning electron photomicrograph of a bleb ofbitumen @) from the Cambrian Bonneterre Formation'Missouri.

Frc. 12. Scanning electron photomicrograph illustratrngvesicles in a bleb of pyrobitumen @) partially encasedby sepiolite (S).

ogies consistent with an origin by water-washing andthermal alteration of petroleum.

ACKNOWLEDGEMENTS

We gratefully acknowledge Rio Algom Ltd. foraccess to the Panel mine. f'insaqial support for thisresearch was provided by the Bowling Green StateUniversity Graduate School and the Department ofGeology Research Fund.

r67

168 THE CANADIAN MINERALOGIST

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