Geology and Metamorphic Petrology of Variably Altered Volcanic Rocks in the Southern Reindeer Lake Area, Northern Saskatchewan

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1 Geology and Metamorphic Petrology of Variably Altered Volcanic Rocks in the Southern Reindeer Lake Area, Northern Saskatchewan Donald M Wright 1, Kevin M Ansdell 1, David Corrigan 2, and Ralf 0. Maxeiner Wright, D.M., Ansdcll, K.M., Corrigan, D., and Maxeiner, R.O. ( 1999): Geology and metamorphic petrology of variably altered volcanic rocks in the southern Reindeer Lake area, northern Saskatchewan; in Summary of Investigations 1999, Volume 2, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep The Reindeer Lake area has been the recent focus of detailed lithological and structural mapping by the Saskatchewan Geological Survey (Maxeiner, 1996, 1997, I 998, this volume) and the Geological Survey of Canada (Corrigan et al., 1997, 1998a, l 998b, this volume). Metamorphosed and altered volcanic rocks and associated sedimentary rocks forming the northeastern extension of the Central Metavolcanic Belt were identified in the Reindeer Lake area (Sibbald, 1977; Stauffer et al., 1979, 1980). These rocks were subsequently subdivided into two belts by Maxeiner (1997), called the Reed Lake and Lawrence Point volcanic belts, and continue to be refined (Maxeiner, this volume). Corrigan et al. (l 998a, this volume) recognized volcanic and sedimentary rocks, including iron formation, in the Laxdal-Doucet islands area, and interpreted these as a northern extension of the La Ronge Domain. The purpose of this ongoing study is to characterize the petrology and metamorphic paragcnesis of all these supracrustal rocks, as well as to determine their possible protoliths and depositional environment. 1. Regional Geology The study area is located in the La Ronge Domain, which was accreted to the margin of the Archean Hearne craton prior to terminal collision at ca. l.83 Ga. (Bickford et al., 1986; Lewry et al., 1990). The La Ronge Domain is thrust onto the Kisseynew Domain to the south (Figure l ), which comprises the highly deformed and metamorphosed rocks of the Bumtwood Group and the structurally overlying Sickle-McLennan elastic sediments (Johnston and Thomas, 1984, Corrigan et al., 1999). The La Ronge Domain is flanked to the north by the Tonalite-Migmatite Complex of the Rottenstone Domain, which is characterized by a greater proportion of calc-alkaline plutonic rocks (Crowe Island Complex) and is interpreted as the plutonic root of the La Ronge arc (Corrigan et al., 1998a; 1999). Also to the north, and structurally above the volcanic rocks of the Central Metavolcanic Belt, are two distinct sedimentary assemblages: the Milton Island assemblage, consisting of graphitic metaturbidites interpreted as an inter-arc basin co-cval with the Central Metavolcanic Belt (Corrigan et al., 1997); and the Park Island assemblage, consisting ofpolymictic conglomerate grading stratigraphically upwards into magnetitebearing arkose and psammite. The Park lsland assemblage is interpreted to have been deposited in a foreland basin on the southern margin of the Hearne craton (Corrigan et al., 1998a, 1999). 2. Field Relationships in Study Areas The two areas chosen for study (Figure 1) include two splays of the Central Metavolcanic Belt: the Reed Lake and Lawrence Point volcanic belts, described by Maxeiner ( 1997, 1998, this volume) and Corrigan et al. {I 997, 1998b), and a supracrustal assemblage that includes volcanic and sedimentary rock, as well as oxide and silicate facies banded iron formation on Laxdal and Doucet islands (Corrigan et al., I 998a, 1999). Some geological and mineralogical characteristics of the Reed Lake and Lawrence Point volcanic belts are consistent with those attributed to alteration zones associated with ancient volcanogenic massive sulphide deposits (e.g. Froese, 1997; Dobbe, 1994 ), and banded iron fonnation within the Laxdal and Doucet islands area might represent the more distal component of an ancient hydrothermal system. a) Reed Lake and Lawrence Point Volcanic Belts These rocks, mapped previously by Sibbald ( 1977), Stauffer et al. (1979), Ashton (1979), Maxeiner (1997, 1998, this volume), and Corrigan et al. (I 997, 1998a), and redefined by Maxeiner (this volume) fonn part of a northeastern extension of the Central Metavolcanic Belt (Figure 2). The Reed Lake and Lawrence Point volcanic belts (RL VB and LPVB), separated in this area by the 1858 ±2 Ma Butler Island Pluton (Corrigan, 1999, pers. comm.), are likely two splays of a larger, thicker volcanic belt. Both belts consist of volcanic rocks, altered volcanic rocks, and associated sediments. A distinctive feature of both the RL VB and LPVB is gamct-cordierite-orthoamphibole and cummingtonitegamet schists, previously studied in some detail by Ashton ( 1979). These, as well as associated gossans, might indicate that synvolcanic hydrothermal alteration, a favourable process for the development of volcanogenic massive sulphide deposits, has likely I Department of Geological Sciences, University of Saskatchewan, I 14 Science Place, Saskatoon, SK S7N 5E2. 2 Geological Survey of Canada, Continental Geosciencc Division, ooth St., Ottawa. ON KI A OE9. Saskalchewan Geological Survey 159

2 BIP Butler Island pluton MIP Milton Island pluton MLP McMillan Lake pluton RIP Reynolds Island Biotite-magnetite leucogranite "' " D '5...-~... Mclennan Group (arkose, polymictic ' ' conglomerate, calcareous a rkose) o. '!! J} Hornblende-magnetite monzonite, quartz monzonite ro ::e ~ ' "..!-~ Diorite/quartz-diorite ro 0 -X, ~ Park Island metasedimentary assemblage (arkose, '( X ' polymictic conglomerate, calcareous arkose, psammite) 1///) Milton Island metasedimentary assemblage ',,., (psammite, psammopelite, pel1te), v\ Central Metavolcanic Belt, v ' Volcano-sedimentary assemblages ~ Crowe Island complex (diorit1c to granitic banded ',.,. orthogneiss -- Outline of Reindeer Lake Io krn Figure I -Map displaying the location of the study areas on Reindeer Lake, as well as the main tectonic components within the northwestern Reindeer Zone. Abbreviations: LRD, La Ronge Domain; GD, Glennie Domain; TMC, Tonalite-Migmatite Complex; PLD, Peter Lake Domain; FFD, Flin Flon Domain; SID, South Indian Domain; and C-SBZ, Churchill-Superior Boundary Zone (after Corrigan et al., 1998a; Lewry et al, 1990; Ashton, 1999). occurred in this environment (e.g. Ashton, 1979; Maxeiner, 1998). Both belts are cut by felsic to ultramafic intrusions. Within the RL VB and LPVB, several distinct rock units are recognized. These include mafic calc-silicate rock, intermediate to mafic volcanics with intercalated epiclastic rock, cummingtonite-garnet-bearing schist, cordierite-anthophyllite schist, and intercalated sedimentary rock. Rocks of the mafic calc-silicate unit are fine grained, and generally dark grey to black amphibolites that generally consist of hornblende, plagioclase, and diopside. Garnet is a major component where there are concentrations of calc-silicate minerals (Figure 3). Minor phases include quartz, cummingtonite, titanite, apatite, and calcite. Concentrations of calc-silicate minerals, in the form of bands and pods, consist of diopside, plagioclase, and sometimes garnet. Locally these resemble deformed pillow selvages (Figure 3). Intermediate volcanic rocks are generally lighter in color than the mafic calc-silicate rocks, and include more readily identifiable volcanic features, such as lapilli (Figure 4). They are generally light to medium grey, and fine grained, with hornblende, plagioclase, biotite, garnet, and quartz as major minerals and cummingtonite occurring locally. Cummingtonite±gamet-bearing rocks with pods of cordierite-orthoamphibole schist are a significant unit in both the RL VB and LPVB (Figure 5). These rocks are light to medium grey, fine to locally coarse grained, and are composed of cummingtonite, hornblende, biotite, plagioclase, quartz, and commonly garnet, with anthophyllite, gedrite, cordierite, sillimanite, staurolite, titanite, ilmenite, magnetite, and calcite as minor phases. The cummingtonite and garnet porphyroblasts range in size up to 4 cm in length and 1 cm in diameter, respectively, and are set in a felsic matrix. The garnets are rimmed by fine-grained plagioclase. Stromatic leucosomes composed of quartz and plagioclase locally account for up to 5 percent of the total rock. The cordierite-orthoamphibole rocks (Figure 5) found among the cummingtonite schists are light to medium grey and fine to medium grained. Plagioclase, orthoamphibole (anthophyllite and gedrite), biotite, 160 Summary of Investigations J 999. Volume 2

3 Legend <::::::,. '.;;;. Biotite-mognetite leuc ogranite ( : \ Mclennon Diorite/quortz-diorite, incl. Butler Island Pluton {BIP) // / Milton Island metosedimentory assemblage Central Metavolc anic BeJt Reindeer Lake Colc -silico te :>:gornet-be oring m ofic roc k Intermediate rock Cordierite :>: garnet --- o rthoomphibole schist Infe rred contacts Figure 2 - Generalized geology map of the Mooney-Gawthrop islands (Reindeer Lake) area, showing the spatial relationships between main units (after Corrigan et al., 1997); RLVB, Reed Lake volcanic belt; and LPVB, Lawrence Point volcanic belt. quartz, cordierite, and garnet are the dominant minerals, with sillimanite, staurolite, spinel, and iron oxides as minor phases. There is approximately 5 to 10 percent leucosomal melt, with quartz, plagioclase, and cordierite comprising the major phases. The wide variety of metamorphic phases, as well as the preservation of earlier phases (i.e. staurolite) makes these rocks good candidates for the qualitative determination of P-T conditions. Locally minor amounts ofpsammopelitic rock are found intercalated within the volcanic units. These are commonly fine to medium grained, light to medium brown, and consist primarily of feldspars, quartz, biotite, and minor opaque phases. Locally, these rocks contain iron sulphides and are rust weathering. Figure 3 - Majic calc-silicate rock of the Lawrence Point volcanic belt, showing the calc-silicate pods within a mafic hornblende±garnet-bearing matrix. Outcrop is located on the north side o/gawthrop Island, and the scale card is 9cm long. b) Supracrustal Rocks oflaxdal and Doucet Islands On Laxdal and Doucet islands, north of Amiskit Island on Reindeer Lake, the supracrustal rocks include mafic to intermediate volcanic rock, banded iron formation, interbedded sedimentary rock, as well as abundant tonalitic to gabbroic intrusive rock (Corrigan et al., l 998a, 1999, this volume) (Figure 6). Primary textures in the volcanic rocks are rare, but locally tuffbreccias, Saskatchewan Geological Survey 161

4 ash flows, and other pyroclastic rocks are recognized, as well as possible relict pillows within the mafic volcanic rock. Banded iron formation, found as discrete layers on both islands, consists of silicate- and oxide-facies varieties. The overall association of mafic rocks and banded iron formation suggests subaqueous volcanism. At the structural base of the supracrustal rocks found on both Laxdal and Doucet islands, in indeterminate contact with the "grey gneiss" associated with the Crowe Island Complex described below, are a series of calc-silicate-bearing mafic volcanic and psammitic to psammopelitic rocks overlain by silicate facies banded iron formation (Figure 7). The calc-silicate-bearing mafic rocks are typically fine to medium grained, dark green to black weathering, with a mineralogy consisting of hornblende, plagioclase, quartz, and local garnet, with calc-silicate pods consisting primarily of diopside, plagioc\ase, and garnet. This mineral assemblage is similar to that seen within the mafic calc-silicate rocks of the LPVB. The silicate-oxide facies banded iron formation is medium to coarse grained, and consists of quartz, grunerite, garnet, magnetite, ilmenite, and plagioclase. On the north edges of Laxdal and Doucet islands, sillimanite-bearing psammitic to pelitic rocks are interbedded with and overlie the BIF and mafic calcsilicate rocks (Figure 8). These rocks are fine to medium grained, well foliated, and locally contain sillimanite knots oriented parallel to F 2 axial planes. They also contain significant amounts ofbiotite, potassium feldspar, and quartz, with zircon and monazite as minor phases. Figure 4 - Three to 4 cm long felsic to intermediate lapilli set in a fine grained intermediate volcanic matrix,found on a small island northwest of Wapus Island. Scale card is 9 cm long. Figure 5 - Cordierite-orthoamphibole schist from the east edge of Mooney Island, showing long radiating porphyroblasts of acicular orthoamphibole and a weak crenulation cleavage formed during D 1 Scale card is 9 cm long. Overlying the volcanic and intercalated sedimentary rocks of the Central Metavolcanic Belt are clast- to matrix-supported conglomerates interpreted as the basal unit of the Park Island assemblage (Corrigan et al, I 998a, Figure 10). The character of the conglomerates vary. On Laxdal Island, the conglomerate is typically light in color, and is dominated by intermediate volcaniclastic debris. Rare clasts include banded oxide facies iron formation and quartz. All clasts are generally sub-angular in shape and range in size up to 20 cm in length. The matrix of these rocks is typically light to medium grey in color, fine to medium grained, with a mineral assemblage consisting of hornblende, biotite, plagioclase, quartz, and magnetite, and the rock is poorly to moderately foliated. On Doucet Island, both matrix and clasts of the conglomerate are more mafic in character, primarily due to an increased magnetite component. Clasts of banded oxide facies iron formation are more abundant and those of volcaniclastic debris less so. The occurrence of conglomerate found on Doucet Island is distinct from that seen on Laxdal Island, but they are interpreted as the same unit due to their structural location and generally consistent composition. Intruding and obscuring the contacts and relationships between most of the above described units are late, medium- to coarse-grained, foliated tonalitic sheets and later undeformed pegmatite dykes. The interpretation of the conglomerates as marking the base of the Park Island assemblage, as well as possible Bouma sequences within the pelites intercalated with the 162 Summary of investigations 1999, Volume 2

5 56'56' Reindeer Lake Le gend Pork Island assemblage " Pluton~ Rocks - Unconformity --- N t Milton Island assemblage Crowe l~and Compex including grey gnciss' CalC-siricate-beanng rno ric rock - Banded Iron Fo rmatio n Psamm,tic to psammopelitic roc k Interred l km Contacts Figure 6 - Map of the Laxdal and Doucet islands area, showing the relationships between the volcanogenic, sedimentary, and plutonic rocks (after Corrigan et al., 1998a, this volume). volcanics, suggests that the rocks on these islands young towards the north. To the south on both islands, the mafic calc-silicate rocks are in contact with a "grey gneiss" of uncertain origin, previously interpreted as an orthogneiss correlated with the Crowe Island Complex of Corrigan et al. ( I 998a, 1999). In general, this rock is medium to coarse grained, composed primarily of quartz, potassium feldspar, biotite, and plagioclase, and is highly strained, resulting in a straight gneissic character. Partial melting in some areas has resulted in the production of a diatexite, with only biotite schlieren remaining of the original rock. Locally, partial assimilation of earlier gabbroic to granodioritic rock has resulted in compositional and textural variations of the "grey gneiss". This unit is also cut by a medium- to coarse-grained, foliated tonalite and later pegmatites. Contacts with surrounding assemblages are not exposed, so direct relationships may only be inferred. 3. Metamorphic Relationships Three phases of deformation have been delineated within the rocks of the RLVB, LPBV, and Laxdal and Doucet islands (Stauffer et al., 1979; Maxeiner, 1996, 1997, 1998; Corrigan et al., 1997, 1998a, I 998b, 1999). Mineral and textural characteristics related to the D 1 event are restricted to very fine-grained fabrics and textures, such as biotite grains, the long axes of which parallel S 0 These characteristics are commonly overprinted by D 2 textures. The D 2 event is contemporaneous with the peak rnetamorphic grade, and coincides with the growth of amphibolite grade metamorphic minerals, including amphiboles, garnet, and recrystallized biotite. Regional-scale D 2 structural features include south-verging reclined to recumbent Figure 7 - Majic calc-silicate rock and silicatefacies banded iron formation, with lens cap for scale. Outcrop is located on the northeast edge of Laxdal Island, with the top of the photograph/acing west. Figure 8 - Matrix supported conglomerate, consisting of tectonically flattened angular clasts of intermediate volcanic composition, set in an intermediate matrix,found structurally overlying the maflc calc-silicate and sedimentary rock to the south. C/asts are elongate parallel to SJ foliation, as well as F 2 fold a.xes, and have been refolded by F 3 folds. Outcrop located within a small bay on the north edge of Laxdal Island. Hammer for scale. Saskatchewan Geological Survey /63

6 folds and south verging thrust faults (Corrigan et al., l 998a, 1999). The 0 3 event is characterized by northtrending open upright F 3 folds, and greenschist facies metamorphism, possibly related to uplift. The M 1 metamorphic event is interpreted to have occurred over both 0 1 and 0 2 events, but the greenschist facies metamorphism related to D 3 uplift is interpreted as a separate metamorphic event (M 2 ). The lithotectonic assemblages within the RL VB, LPVB, and the Laxdal and Doucet islands areas include variably altered volcanic and sedimentary rock. The cordierite-anthophyllite assemblage of the RL VB provides the best source of peak metamorphic P-T information for that region, while the petites oflaxdal Island provide the best assemblage for delineating the P-T conditions for that area. The combination of the P T information from both areas allows for the constraint of overall P-T conditions in the southern Reindeer Lake area. The mineral assemblages associated with each respective rock type are summarized in Table 1. The reaction space outlined by the cordieriteorthoamphibole schists on Figure 9 is the result of several observations. First, the occurrence of sillimanite and anthophyllite as inclusions within cordierite grains (Figure 10) suggests that they predate the growth of these particular cordierite grains, but also sheds light on the possible path these rocks followed in order to reach this point. The first occurrence of aluminosilicate is represented by 1 on Figure 9, where it is bracketed at a lower temperature by the reactions St+Crd----)Oa+As and/or St----)Crd+Alm+As. The lack of relict cordierite or garnet preserved within anthophyllite or sillimanite suggests that any early cordierite or garnet were entirely consumed by the prograde reaction Crd+Alm----)Oa+As. However, staurolite inclusions within cordierite observed by Ashton (1979) within these rocks may represent a relict of the earlier St----)Crd+Alm+As reaction. Again due to the inclusion of sillimanite and anthophyllite within cordierite, these rocks are interpreted to have undergone decompression, passing back over the Oa+As----)Crd+Alm reaction curve (2 on Figure 9). The lack of orthopyroxene within these rocks allows for the upper temperature of these rocks to be constrained by the reaction Cum+Alm----)Oa+Opx. Lower pressure conditions are constrained by the Oa+Alm----)Crd+Cum reaction curve, as no cummingtonite was observed. This is a tentative lower limit, as full mineralogical analysis of the amphiboles has not been completed. Coexisting gedrite and anthophyllite have, however, been observed within these rocks, and likely represent conditions marked by 3 on Figure 9. This occurrence is interpreted to represent a part of the retrograde path, as it plots well away from the "peak" conditions. The pelitic schists of the Laxdal and Doucet region are the most useful indicators of P-T condition for that area, and the resultant P-T space is outlined on Figure 9. The assemblage sillimanite+potassium feldspar+ biotite+plagioclase+quartz is typical for the upper amphibolite facies. The reaction muscovite+quartz----) sillimanite+potassium feldspar and the presence of quartzofeldspathic leucosomes within these and the surrounding rocks help delineate the lower temperature conditions of these rocks. As neither cordierite nor orthopyroxene have been observed, the upper limit of temperature is constrained by the reactions Bt+As----)Crd+Alm+Ksp and Bt+A]m----)Crd+Opx+Ksp. Satisfactory limits on pressure are not as well defined by this assemblage, but the lower limits are defined by the conversion of the Qtz+Pl+Ksp+H )melt and the Bt+As----)Crd+Alm+Ksp reaction curves. Upper limits on pressure are defined by the lack of kyanite within this assemblage. The two areas represented by the two metamorphic assemblages are separated by approximately 30 km distance, but there are no major structural boundaries between the units, allowing for their combined use in the determination of peak P-T conditions for this region. The combination of the stable reaction assemblages exhibited by these two rock types is outlined by the fully shaded area on Figure 9. The conditions represented by this area constrain P-T conditions for the supracrustal rocks of the area at approximately 680 to 710 C and 4.8 to 6.5 kbar. These conditions agree with P-T conditions outlined by Ashton ( 1979) for the Mooney Island area. 4. Summary The RL VB and LPVB, and the Laxdal and Doucet islands area are interpreted to form part of the La Ronge Domain in the southern Reindeer Lake area (Maxeiner, 1997, 1998;Corriganeta/., 1997, 1998a, l 998b, this volume). These areas are predominantly underlain by volcanic and intercalated sedimentary rock as well as compositionally variable intrusive rock. Some rocks of the area show evidence of premetamorphic seawater and hydrothermal alteration, represented by cummingtonite-gamet and cordieriteanthophyllite assemblages. Peak metamorphic Table 1 - Metamorphic mineral assemblages of the primary rock types used in P-T determinations. Major phases (>5 percent) are indicated by a star (*), and minor phases (<5 percent) by a dash (-). Anthophyll ite/ Potassium Rock Type Gedrite Cordieritc Gamet Sillimanite Biotite Pl agioclase Feldspar Cordierite+orthoamphibole-bearing schist Pelitcs 164 Summary of investigations I 999, Volume 2

7 -- rj) '- ('Cl 8-6..c 5 ~ KYANITE "!' u Stauffer and Dave MacDougall, have been extremely helpful. The assistance of Blaine Novakowski and Tom Bonli at the University of Saskatchewan is also greatly appreciated. The major funding for this project comes from an NSERC grant to K.M. Ansdell, as well as logistical assistance from both the Saskatchewan Geological Survey and the Geological Survey of Canada. Reviews by Drs. Ken Ashton and Gary Delaney greatly improved the manuscript. (I) '- :J ~ 4 -- ()) '- a.. noncalcic I 500 I ANDALUSITE I I I 600 Temperature ( C) I 700 Mineral Abbreviations nonpotassic potass1c As - Aluminosilicate Ms - Alm -Almandine Ksp - Potassium Feldspar Muscovite 6. References Ashton, K.E. (1979): The geology of the Milton Island map sheet ( east half), Saskatchewan (64D-10E), unpubl. M.Sc. Thesis, Univ. Sask., 13 lp. -~~_(1999): A proposed lithotectonic domainal reclassification of the southeastern Reindeer Zone in Saskatchewan; in Summary of Investigations 1999, Volume 1, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep , p92-l 00. Bt - Biotite Oa - Orthoamph1bole Bickford, M.E., Macdonald, R., Chi - Ch lorite Opx - Orthopyroxene Lewry, J.F., and Pearson, Crd - Cordierite Pl - Plagioclase J.G. (1986): U-Pb zircon Cum - Cummingtonite Qtz - Quartz Hbl - Hornblende geochronology project for the Trans-Hudson Orogen: Figure 9 - P-T grid displaying the inferred P-T path of the discussed metamorphic assemblages. Lightly shaded area represents the stable cordierite-orthoamphibole assemblage, darkly shaded area represents the stable pelite assemblage, and the fully shaded area represents the P-T area of the combined stable assemblages. Numbered circles are referred to in the text. Locations of reaction curves in P-T space after Froese (1997 and ref therein) and Spear (1980, 1993). Current sampling and recent results; in Summary of Investigations 1986, Saskatchewan Geological survey, Sask. Energy Mines, Misc. Rep 86-4, plol-107. temperatures appear to be constrained between 680 and 710 C, with an upper pressure constraint of approximately 4.8 to 6.5 kbar. Further geochemical investigation of both the altered and unaltered volcanic rocks will likely shed light on both the tectonic setting of these assemblages, as well as the extent and type of alteration present (e.g. via mass balance calculations, Gresens, 1967). 5. Acknowledgments The assistance and camaraderie oft.g. MacHattie, J. Chakungal, B. Lassen, L. Piper, S. Pehrsson, T. Prokopiuk, R. Morelli, A.Williamson, and C. Huebert, as well as discussions with Dr. Mel Corrigan, D., Bashforth, A., and Lucas, S. ( 1997): Geology and structural evolution of the La Ronge Lynn Lake Belt in the Butler Island area (parts of and -10), Reindeer Lake, Saskatchewan; in Summary of Investigations 1997, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 97-4, p Corrigan, D., MacHattie, T.G., Piper, L., Wright, D., Pehrsson, S., Lassen, B., and Chakungal, J. (I 998a): La Ronge-Lynn Lake Bridge Project: New mapping results from Deep Bay (parts of 64D-6 and -7) to North Porcupine Point (top of 64E-7 and -8), Reindeer Lake; in Summary of Investigations 1998, Saskatchewan Geological Saskatchewan Geological Survey 165

8 North America; Geol. Assoc. Can., Spec. Pap. 37, p Maxeiner, R.O. (1996): Bedrock geology of the Henry Lake area (parts ofnts and-11), northern La Ronge Domain; in Summary of Investigations I 996, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 96-4, p ~~~- (] 997): Geology of the Lawrence Bay (Reindeer Lake) area, northeastern La Ronge Domain; in Summary of Investigations 1997, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 97-4, p3-17. Figure 10 - Photomicrograph of sillimanite inclusions within a cordierite grain, showing the mineral relationship associated with a decompression reaction. View is approximately 1 mm in width. Survey; Sask. Energy Mines, Misc. Rep. 98-4, plll-122. Corrigan, D., Maxeiner, R.O., Bashforth, A., and Lucas, S.B. (I 998b ): Preliminary report on the geology and tectonic history o~the Trans-Hudson Orogen in the northwestern Remdeer Zone, Saskatchewan; in Current Research, Part C; Geol. Surv. Can., Pap. 98-lC, p Corrigan, D., Pehrsson, S.J., MacHattie, T.G., Piper, L., Wright, D., Lassen, B., and Chakungal, J. (1999): Lithotectonic framework of the Trans Hudson Orogen in the northwestern Reindeer Zone, Saskatchewan: An update from recent mapping along the Reindeer Lake transect; in Current Research 1999-C, Geol. Surv. Can., p Dobbe, R.T.M. (1994): Geochemistry of cordieriteanthophyllite rocks, Tunaberg, Bergslagen, Sweden; Econ. Geol., v89, p ~~(1998): Geology of the Birch Point (Reindeer Lake) area, northeastern La Ronge Domain; in Summary of Investigations 1998, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 98-4, p8 l-99. Sibbald, TI.I. (1977): The Geology of the Milton Island Area (west halt); Sask. Dep. Miner. Resour., Rep. 153, 38p. Spear, F.S. (] 980): The gedrite-anthophyllite s'?lvus and the compositional limits of orthoamph1bole from the Post Pond Volcanics, Vermont; Amer. Mineral., v65, pl ( 1993): Metamorphic phase equilibria and --p-re-s-su-re-temperature-time paths; Miner. Soc. Amer., Mono. Series, 799p. Stauffer, M.R., Langford, F.F., Coleman, L.C., and Mossman, D.J., (1979): Geology of the area around Amiskit Island, Reindeer Lake; Sask. Dep. Miner. Resour., Rep. 191, 21p. ( 1980): Geology of the Reindeer Lake --N~o-rt~h- (=Southeast) Area; Sask. Dep. Miner. Resour., Rep. 200, 21p. Froese, E. (1997): Metamorphism in the Weldon Bay Syme Lake area, Manitoba; in Current Research 1997-E, Geol. Surv. Can., p Gresens, R.L. ( 1967): Composition-volume relationships ofmetasomatism; Chem. Geol., v2, p Johnston, W.G.Q. and Thomas, M.W. (1984): Compilation Bedrock Geology Series, Reindeer Lake South NTS Area 64D; Sask. Energy Mines, Rep. 230, I '.2so 000 scale map with marginal notes. Lewry, J.F., Thomas, D.J., Macdonald, R., '.1nd. Chiarenzelli, J. (1990): Structural relatwns m accreted terranes of the Trans-Hudson Orogen, Saskatchewan: Telescoping in a collisional regime?; in Lewry, J.F. and Stauffer, M.R. (eds.), The Early Proterozoic Trans-Hudson Orogen of 166 Summary of Investigations 1999, Volume 2

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