metamorphism of hydrothermal alteration at the red lake mine, balmertown, ontario PDF
Preview metamorphism of hydrothermal alteration at the red lake mine, balmertown, ontario
METAMORPHISM OF HYDROTHERMAL ALTERATION AT THE RED LAKE MINE, BALMERTOWN, ONTARIO by GI Clark Darner A thesis submitted to the Department of Geo1ogical Sciences in conformity with the requirements for the degree of Master of Science Queen' s University Kingston, Ontario, Canada July, 1997 copyright 8 0. Clark Damet National Library 8ibliiuen ationale du Canada Acquisitions and Acquisitions et Bibliogtaphic Services services bibliographiques The author has gmted a non- L'auteur a accord6 m el icence non exclusive licence allowing the exclusive permetbmt a la National Library of Canada to Biblioth- nationale du Canada de reproduce, loan, distn'buie or sell repfoduire, p&k, distri'buetou copies of his/her thesis by any means vendre des copies de sa these de and in any form or format, making qyelqpe mmi&e et sous qpe1cpe this thesis avallsrblle to interested fome que ce soit pour mettre des persons. exemplaires de cette t h ha la disposition des personnes int&essCes. The author retains ownership of the L'auteur coaserve la propriCt6 du copyright m hismet thesis. Neither &oit &auteur qyi prot&ges a th&se.N i the thesis nor substantial extra& la these ni des extraits substantiels de fkom it may be printed or othemk ceJle-ci ne doivent &R imp1im6s ou reproduced with the author's autrement nppoduits sans son permission. autorisation. Frontispiece: The DeHavilland Norseman in downtown Red Lake. The Norseman was one of the first bush planes and played a major role in the Red Lake gold rush during the 1920's. Abstract The Rcd Lake Mine is a metamorphosed Archean gold deposit. It is located within the Red Lake greenstone belt of the Uchi Subprovin~in the northwestern portion of the Superior Province. Highly altered basaltic rocks in the Red Lake Mine have similar mineral assemblages to those observed in pelitic rocks. The highly altered rocks have Mered extensive premetamorphic hydrothermal alteration largely by the addition of K20, FeO and C* with almost the complete removal ofNa20. Blrllr rock CaO and A1203 are residually enriched. The maximum-phase mineral assemblages consists of: Grt+Bt+Chl+St+Cld+And+PL+Qtz+Ilm+Ank+Tm~C orn in altered rnetabasalts. The mineral assetnbleges preserved in the Red take Mine demonstrate that the transition fmm pellschist m amphibolite facies assemblages in weakly altered basaltic rocks occurs before the staumlitein isograd in highly altered basaltic rocks (essentially pelites) with alPll[ljllous assemblages. The low-variance mineral assemblages could have only arisen by the metamorphism of high-variance assemblages. Zoned hydmthemal alteration patterns have been preserved around ore-bearing zones. The "Main Zone" is enveloped by three minetalogically distinct maximum-phase mined assemblages: (1) Chl + P1+ Grt + And + Qtz + St + Cld + Bt + Ilm f Cum (Distal) (2) Hbl + Bt + Chl + P1+ Qtz + An.+ Mt + Dm f Ath (hermediate) (3)Bt+Ank+Qtz+Ms+Pl+Mtf Chl (Proximal) The zoning of mineral assemblages amund the "Main Zone'@at the Red Lake Mine represents metamorphism of hydrothermal alteration. The outer zone is inferred to have formed from a pmtolith rich in kaolinite (Le. a zone of advanced atgillic alteration). The intermediate zone may have formed from a chlorite-rich protolith (Lee a zone of intemediate argillic alteration or chloritization). Close to the ore-bearing structure, the proximal zone is inferred to have formed from a protolith rich in biotite, muscovite, quartz and ankerite (i-e. a zone of potassic alteration). During metamorphism, hydrothermal biotite, muscovite, chlorite, quark and ankerite are irrferred to have recrystallized and re-eqpilibrated with newly formed minerals such as garnet, staurolite and chloritoid while the lower temperature hydrothermal clay minerals in the outer zone were completely replaced by the newly formed minerals. Two hogcads have been mapped in the undetgtound workings of the Red Lake Mine: the staumlite-in isognd and the chloritoid-out isograd. The isograds strike approximately N2WE and dip 300Wwheceas the mine stratigraphy strikes approximately N45W and dips between 40-750W. Thetefore, isograds cross-cut the mine stratigraphy, alteration and ore zones, The low-variance mineral assemblages permit accurate definition of the P-'I' conditions of metamorphism. Two computer aided themobammetric programs were used to calculate pressures and temperatures: TWEEQU and WEBINVEQ, Pressures and temperatures vary systematically within the mine from 1400-2000 bars and 435- 4 8 mw ith TWEEQU and 1000-220 bars and 450-550% with WEBINVEQ. The PC% displays a systematic decrease with depth in the mine. P-T results indicate a very high geothermal gradient of about 70-900Cflrm. The high geothermal gradient is consistent with contact metamorphism by a nearby heat source (Lee the Walsh Lake Pluton) at depths between about 6-7 km. Acknowledgments I would not have been able to complete this thesis if it wee not for the help of a great many people. First of all I wodd like to thank Dr. Dugald Cannichael who suggested this thesis topic and for giving me many valuable lessons along the way, both intellectual and financial as well as recreational. Your enthusiasm and sopport is greatly appreciated. I would also like to thank Goldcorp Inc. for allowing me access to their mine and for providing food and lodging while I was in Balmertown. The time I spent undergro~dw ith Steve McGibbon, Tim Twomey, Dan Lemm and Steve Duenck is greatly appreciated. I would also like to thank Bob Chathaway for many interesting discwioas and for taking me golfing in Balmertown. Rob Penaak, now at Goldcorp Inc., provided many interesting discussions and was able to take time out of his busy schedule to collect some more samples for me. For this I owe you more than just a couple bars. I would also like to thank Tom Stubens and John Misiura of Placer Dome Canada Ltd. for giving me a tour of the Campbell Mine on such short notice. At Queen's University my educational experience was greatly enhanced by many of the professors especially, Dr. Alan H. Clark and Dr. Herb H. Helmstaedt I would also like to thank Dr. Bob Mason for many enlightening conversations on the geology of Archean gold deposits. Many other discussions on various aspects of the thesis with Dr. Doug A Archibald, Dr. C. lay Hodgson, Dr. Peter L. Roeder, Dr. Heather Jamison and Dr. John Hanes are greatly appreciated. A "HUGE BIG thanks goes out to all my Sends at Queen's especially those from the "Gro6e Namrwi~sentschaftler.~Mi' ke "Ooley"C ooley, "Newfie"D ave Gale and Gord Stretch have provided constant friendship from the beginning. I would also like to thank Tom Ulrich for his help with just about everything in the department from microscopes to computers. You should charge more for consulting fees. Most of all I would Wre to thank Rosalind Stephanian for her continued support and encouragement especially throughout this last year. You have proven to w that if someone can switch fkom German literature to geology that anything is possible. Du bist mein gold scisatz. This wok was financially supported by a Reinhardt Fellowship and a Queen's Graduate Award and by an NSERC research grant to Dr. DugaId M. Carmichael. ...........................1.....1.. .....G...e...n....e...r....a...l... ..h.....t..t...o....d.....w......t...i..o.... 1 ................................................................................ 1.2 hvious wor k....................... 4 ....................................................................... 1.3 Scope and Objectives of the Thesis 2.1 Introduction. ......................................................................................................... ..................................................................................... 2.2 Supracrustal Assemblages ..................................................................................................... 2.3 Intrusive Rocks ............................................................................... 2.4 Geology of Balmer Township 2.5 Mine Geology ...................................................................................................... ............................................. 2.6 Structural Geology, Alteration and Miaetalization ................... ...............*....................................... 2.7 Summary of Geo10gical Events .......................................................................................................... 3.1 Introduction ........................................................................................... 3.2 Mineral Assemblages 3.2. 1 Sedimentary Rocks ........................................................................................... ............................................................................................... 3.2.2 Ultramafic RQCkS ....................................................................................... 3.2.3 Felsic Extrusive Rocks 3.2.4 Felsic Intrusive Rocks ....................................................................................... 3.2.6 Basaltic Ro& ................................................................................................... .................................................................................................................. 3.3 Garnet, 3.4 Ph@~~laseo~*e.*o.~**o~*~*~~*~~*~e*~~*e**~~m~***~~~~*~~~~~~m~*~~*~~~*mmm*a~~*~m~~o**-~~---*~me~~*~o~~~*~*~o-~~--~~~~v~ .......................................................................................................... 3.5 Amphiboles 3.7 Chlorite. ............................................................................................................... . ............................................................................................................ 3.13 Codte nte 3.14 Other Mined. ................................................................................................... 3.15 Mineralogical Profile of the 'Main Zone" on the 34th Level. .............................. 3.16 Significance of the transition fkom Chlodtoid- and Statxolite-bearing ......................................................................~......~......................... Assemblages ......... .. .........*......*.o....e...3...17. .D*is.c.u.ss.igo.n ..... 4.1 hfMduction. ....................................................................................~.................... 95 ............................................................................................... 4.2 Analytical Methods 98 4.3 Results of Thermoberometry. ................................................................................ 99 4.4 T-XC* Conh-h9o a s. .......................................................................................... 120 4.5 Discussion ....g..e.................................................................................................. I2!5 ............................................................ APPENDIX 2 MlCROPROBE DATA.... 151 = List of Figures ............................. Figure 1.1. Location map of the Red Lalre and the Uchi Subp rovince 2 ........................................................................ Figure 1.2. Township map of Red Lake 3 ................. F i p2 1. Genedhdm ap of -tone belts in the Uchi Subprovince 13 ................................ Figure2.2. Simpfifiedgeo108yoftbeRsd~~mtoaebelt 15 ..... Figure 2.3. St ratigqhic subdivisions of the Rcd Lake greenstone by Pirie (198 1) 16 Figate 2.4. Stratipphic subdivisions of the Red Lake gmenstone ........................................................................... by Wallace et aL (1986) 16 Figure 2.5. Tectonic assemblage map of the Red Lake greenstone belt by .............. Stott and Corfi,( 1991) ............................................................... 18 ......................................................... Figrue 2.6. Geology map of Bialmer Tow aship 24 Figure 2.7. Complilation geology map of the 14th level of the Campbell Mine ................................................... and the 15th level of the Red Lake Mine 28 ......................................... Fipe2 .8. Schematic cross-section of the Red take Mine 29 .................... Figure 3.1. ACF diagram of altered basaltic rocks in the Red Lake Mine 41 .......... Figure 3.2. Graph of 2x10 versos apparent Na20 in EDS analyses of staurolite 73 ................................................ Figure3.3. Mimra10gicalpcoNeoftbe'~Mainne" 84 ..................*. Figure 3.4. Schematic cross-section of the Red Lake Mine with isograds 89 . ............ ....................... Figure 3 5 Geology map ofBalmerTowllship withisograds 90 Figure 3.6. Complilation geology map of the 14th level of the Campbell Mine ..... and the 15th level of the Red Lake Mine with the staurolite-in isograd 91 ...................................... Figure 4.1. TWEEQU plot of sample 2413 with chloritoid 101 ................ ............. Figure 4.2. TWEEQUand WEBINVEQplot of sample 15-017A 102 ......................... Figure 4.3. TWEEQU and WEBINVEQ plot of sample 28-886-2D 105 .............................. Figure 4.4. TWEEQU and WEBINVEQ plot of sample 2e88.1 107 .......................... Figure 4.5. TWEEQU and WEBINVEQ plot of sample 3462364 109 - .............. .... ........... Figure 4.6. Garnet biotite thermometer of sample 9521-1 112 Figure 4.7. TWEEQU and WEBINVEQ plots of sample 2413 without ........................................................ chloritoid md with varying Xa20. 113 Figure 4.8. Schematic cross-section of heR ed Lake Mine with isograds . .................................................................................. and P-T vanahons 117 Figtm 4.9. Schematic petmgenetic grid of the "ideal"p elitic system .........................................~.............................................. with bathomnes 118 ...... ................. . ... Figure 4.10. Petrogenetic grid from Spear and Cheney (1989) 119 Figate 4.1 1. Sequence of TWEEQU plots of sunple 28-886-2D with varying m20 .. -.... .....*...................*..........................1.2. 1 ......m em...... Figure 4.12. T - X q diagram illustrating the effects of P and X* on the stability of the banded quartz-te veins ......................................... 123 Figure 4.13. T - X qd iagram frmn Chdstie (1986) ...........,~.m.......~.........~.........1..2.4s ..s List of Plates ..................................... Phte 2.1 Pillowed tholciitc b d t so f the Bslmer Assemblage 19 ........................ Plate 22 Tightly folded sediments of the Bruce Channel Assemblnge 25 ........................................... Plate 23 "Lamprophymn cmss-cutting the "SC" ore m e 33 ...... Plate 3.1A Two textural generatioas of chloritoid with sygmoidal inclusion trails 43 .............................................................. Plate 3.1B. Howglass structure in chloritoid 43 Plate 3.2 Latetectonic mddas i t e ~ ~ . m ~ e ~ ~ ~ ~ ~ ~ ~ ~ ~ m m ~ a ~ ~ m ~ ~ ~ ~ e ~ 4~9~ ~ ~ ~ ~ e ~ ~ ~ ~ L 8 . ~ ~ ~ e ~ . ~ C ~ ~ ~ * * ~ ~ ~ ~ ~ ~ ~ O ~ ~ e * . ~ ~ * * m * ~ ~ ~ ~ ~ ~ ................. Platc3.3 Lngepoikiloblastofcordieritewithzinciaasta11lolitehclUSio~~ 49 .............................. PUe 3.4 Blue quartz "eyes" in the "CampbelyDickensond iorite" 50 Plate 3.5 kuartz in the "CampbelyDickensond iorite" .............................................. 50 Plate 3.6 Garnet porphymbest in a QF P......e.............................................................. 53 ......... Plate 3.7 Garnet with ab~danitn clusions of arsenopyrite. pyrite and magnetite 58 . .................... Plate 3 8 Late-tectonic garnet porphyroblast with biotite and plapio clase 58 .................................... Plate 3.9 Cdcic plagioclase with conspicom radial extinction 62 ................... ... Plate 3.10 Calcic plagiochse with yellow-geen cathodolumiuescence 62 .......................................................... Plate 3.1 1 Clunmingtonite inclusions in gamet 65 ....... ........... . Plate 3.12 Magnesia-hornblende in the matrix of a cockade breccia. 65 Plate 3.13 Radiating anthophyllite in a vein ...............................................................7 0 .................................................................. Plate 3.14 Biotite intergrown with chlorite 70 ................................ Plate 3.15 Latetectonic stamlite and chloritoid porphyrob lasts 76 ...................... Plate 3.16 Ephedral mdalusite porphyrobhts in a deformed quartz vein 76 Plate 3.17A Matgarite in metasediment with muscovite. ............................................. 79 ........ Plate 3.17B Cmndated margarite in metasediment with muscovite end andalusite 79 ............................ Plate 3.18 Rumortierite with biotite in the East South "C" ore zone 82 ........... Plate 3. 19 Dunortierite with biotite and stawlite fiom the South "C" ore zone 82 ............ Plate 3.20 Layer of garnet and cumrningtonite from. t he distal alteration zone 85 Plate 3.21 Ptygmatic vein with staurolite. chloritoid plegioclase. and ........ ............ andalusite h m t he distal alteration zone ................................. 85 - Plate 3.22 Magnesio hornblende and anthophyllite in the intermediate alteration zone ........................................................................8. 7 Plate 3.23 Equigranulat intergrowth of biotite. ankerite, quartz, arsenopyrite. pyrite and magnetite from the proximal alteration zone. ...............................8 7
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