The Crater Island Assemblage, Amisk Lake (Part of NTS 63L-9} 1

B.A. Reilly

Reilly, B.A. (1994): The Crater Island Assemblage, Amisk Lake (part of NTS 63L-9); in Summary of Investigations 1994, Sask­ atchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 94-4.

The main objective this summer was to complete revi­ the past few years coupled with geochemical and iso­ sion mapping of the south-central Amisk Lake area, and tope studies (Watters et al., in press; Stern et al., in improve the understanding of the relationships between press a and b) has led to the recognition of several dis­ the West Amisk and Muskeg Bay assemblages to the tinct lithotectonic assemblages (Figure 1) (Reilly et al., west and the Sandy Bay Assemblage to the east. Ap­ in press) in the region. proximately 200 km2 were mapped at 1:50 000 scale during the month of August in an area extending from Greenstone assemblages on the west side of Amisk the south shore of Missi Island to the edge of the Pre­ Lake are dominated by 1882 to 1888 Ma (Heaman et cambrian Shield at the south end of Amisk Lake (most al., 1993; Stern and Lucas, in press) felsic to intermedi­ of this area is covered by Amisk Lake), thus bridging ate calc-alkaline island arc volcanic rocks underlain by the gap in revisional geological mapping which existed largely tholeiitic island arc basalts2 (Fox, 1976a and b; between the east and west shores of Amisk Lake, ex­ Walker and Watters, 1982; Ashton, 1990, 1992; Watters cluding central and eastern Missi Island. and Ashton, 1991 ; Reilly 1992, 1993; Stern et al., in press a). These have been termed the West Amlsk As­ Detailed revisional bedrock mapping by the Saskatche­ semblage (Reilly, 1993) and the Muskeg Bay Assem­ wan Geological Survey in the Amisk Lake area during blage (Reilly et al., in press), respectively.

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Figure 1 • Lithotectonic assemblages of the Amisk Lake area.

(1) Saskatchewan Project A.112 was funded in 1994 under the Canada-Saskatchewan Partnership Agreement on Mineral Development 1990-95. (2) All of the Precambrian rocks in the map area have been metamorphosed and the prefix meta will be omitted when referring to these rocks.

Saskatchewan Geological Survey 11 On the east side of Amisk Lake, the Sandy Bay As· Typical ab(cd) turbidite sequences and soft-sediment semblage (Slimmon, 1991 b), consists predominantly of slump folds are described by Van Wagoner (1982). tholeiitic MOAB-like basalts (Parslow and Gaskarth, 1984, 1988; Gaskarth and Parslow, 1987; Slimmon, A lower and an upper subaerial sequence dominated by 1991a, 1993; Watters et al., in press, this volume; Slim­ tuff and lapilti tuft have been described by Ayres et al. mon, this volume; Stern et al., in press b). ( 1991) in rocks now included within the Crater Island As­ semblage (Figure 2). In the lower sequence, bedding is This report briefly describes the characteristics, contact generally poorly developed and flows form about 50 per­ relationships, and economic potential of a newly defined cent of the sequence. In the upper sequence, bedding lithotectonic assemblage, namely the Crater Island As­ is well developed and flows form approximately 15 per­ semblage. This assemblage is excellently displayed cent of the sequence. Individual beds, which range in due to lower greenschist facies metamorphism, rela­ thickness from 5 mm to 8 m, in places display graded tively low deformation, paucity of plutons, and the pres­ bedding, although most are ungraded. Accretionary ence of wave-washed, flat-lying, lichen-free shoreline lapilli and armored lapilli occur in many of the beds, and exposures. basal scours and cross-beds are found locally.

A summary of the main features of the lithotectonic vol­ Amygdaloidal flows up to about 1.5 m thick containing canic assemblages of the Amisk Lake area are given in up to 30 percent amygdales of variable size, shape, Table 1. and distribution have been interpreted as subaerial de­ posits by Ayres (1978). Features in support of this inter­ pretation include the presence of basal pipe amygdales, 1 . Crater Island Assemblage thinly chilled upper flow surfaces, and the absence of pillows. The amygdales are generally concentrated in The Crater Island Assemblage comprises a thick mafic the upper part of the flows, average 5 to 1 O mm in size volcanic sequence which outcrops in the south-central but are locally as much as 5 cm long, and range in part of Amisk Lake and extends from lskwasoo Island shape from spherical to irregular. Plagioclase-phyric in the east to the southwest corner of Missi Island in and pyroxene-phyric textures occur locally. Ayres the west (Figure 2). The assemblage forms essentially (1978) recognized pahoehoe toes in one subaerial sec­ a folded sequence about three kilometres thick and tion. comprises largely tholeiitic basalt and basaltic andesite (Fox, 1976a and b; Ferreira, 1984; Gaskarth and Pars­ Coarser volcaniclastic rocks occur as massive to low, 1987). crudely bedded, clast-supported to matrix-supported tuft breccia, lapilli tuff, and minor coarse tuff. Fragments are Physical volcanological studies by Lorne Ayres and rounded to angular with chilled margins, amygdaloidal graduate students at the University of Manitoba have to non-amygdaloidal, monolithic in composition, and been conducted at Amisk Lake since the late 1970s. De­ have an observed maximum size of about 75 cm. The tailed stratigraphic sections concentrating on the Crater matrix consists of coarse tuff and small lapilli of similar Island Assemblage can be found in Ayres (1978, 1980a composition to the fragments. Ayres et al. (1991) de­ and b, 1981), Ferreira (1981), Van Wagoner (1982), scribes these coarser volcaniclastic rocks in terms of Van Wagoner et al. (1982), Ferreira (1984), Van two emergent and one intervening submergent zones of Wagoner and Van Wagoner (1987), and Ayres et al. flow foot breccia produced when lava entered the ocean. (1981 , 1991). Gabbro is a common component of the Crater Island The Crater Island Assemblage is composed of approxi­ Assemblage. Fine- to medium-grained dykes and sills mately equal amounts of lava flows and intercalated vol­ range from less than one metre to 500 m in width. canic\astic rocks of basaltic composition. Subaqueous Chilled margins are found in places and rhythmic igne­ massive to pillowed lava flows are the dominant rock ous layering is typically associated with the larger_ i~tru­ type and range in thickness from 3 m to greater than sions. The similarities in appearance and compos1t1on, 50 m. Plagioclase-phyric flows are more abundant than and intimacy of association of the gabbro and basalt aphyric flows. Phenocrysts generally comprise no more country rock suggests that the gabbro is synvolcanic. than 5 percent of the flow and are typically less than 5 mm in size. Microphenocrysts are also characteristic The Crater Island Assemblage is interpreted by Ayres of the plagioclase-phyric flows. Amygdaloidal flows are et al. (1991} as a composite basaltic shield volcano. He commonly intercalated with the massive and pillowed considers that the volcaniclastic rocks were erupted flows. Spherical to ovoid amygdales average less than largely by phreatomagmatic explosions on the coastal 5 mm in size and comprise less than 5 percent of the plain of a rapidly subsiding volcano with low slope an­ flow. Rare olivine-phyric flows are present. gles, and that some tephra w~s subaerially dE:posited as distal surge-and-fall deposits, but the remainder fell lnterflow tuff and lapitli tuff comprise about 40 percent on the upper submarine slopes where it was interca­ of the subaqueous sequences. These volcaniclastic lated with lava flows. units range from massive to bedded, ungraded to nor­ mal graded, and are less than one metre to several hun­ dred metres thick. Ayres et al. (1991) documented 2. Structural Geology and Metamorphism predominantly ungraded units on the west limb of the Winterton Island Anticline and graded units on the east Five main deformation events have been documented limb. Basal scours and flame structures are common. in the Amisk Lake area (Reilly, 1993; Slimmon, 1993):

12 Summary of Investigations 1994 ~ Table 1 - Characteristics of lithotectonic volcanic assemblages of the Amisk Lake area. ~ () ;? Assemblage Sandy Bay Crater Island Muskeg Bay West Amisk

::,i Dominant Lithology Mafic volcanics Mafic volcanics Malic volcanics Felsic to intermediate volcanics G) ~ o" Volcanic Rock Type Lava flows Volcaniclastics lava flows Lava flows > volcaniclastics? Volcaniclastics > lava flows 10 = [ gi Characteristics: Subaqueous aphyric, pillowed Subaqueous massive to pillowed Subaqueous massive to pillowed Subaerial volcaniclastics dominate. ~ flows dominate. Amygdaloidal feldspar-phyric flows dominate. aphyric flows dominate. Feldspar­ Tuff breccia, lapilli tuff, and luff are '<: flows are subordinate; amygdales Aphyric and amygdaloidal flows phyric and amygdaloidal flows are present. Fragments are volcanic, < 5 mm in size and comprise < 5% of are common. Amygdales com­ found locally. Amygdales are < 5 mm heterolithic. and poorly soned. flows. Massive flows and syn­ prise < 5% of flows and are < 5 mm in size and comprise < 5% of flows. volcanic gabbro intrusions are also in size. lnterflow tuff and lapilli tuff Olivine-normative base and quartz· Rare subaqueous volcaniclastics common. Flow breccias occur and synvolcanic gabbro intrusions normative top. Synvolcanic gabbro are chiefly monolithic tuff breccias. locally. are also common. Olivine- and intrusions are common. pyroxene-rich flows are rare. Poorly exposed. Minor subaqueous flows and flow Volcaniclastics are rare. breccias are typically feldspar± Subaerial volcaniclastics of tuff Volcaniclasti cs are rare and found hornblende-phyric. Pillowed flows and lapilli tuff are abundant. near lop. and amygdales are rare.

Accretionary and armored lapilli occur locally.

Minor highly amygdaloidal subaerial flows contain amygdales which average 30% of flows and 5 to 10 mm in size. Pipe amygdales are rare.

Thickness (approximate) 4000 m 3000 m 2500m 3000m

Upper boundary Tectonic Gradation al Gradation al Gradational

Lower boundary Tectonic Unknown Unknown Gradational

Magma Series Tholeiitic basalts Tholeiitic basalts Tholeiltic basalts Cale-alkaline

Tectonic Setting Back-arc/ oceanic plateau Island arc Island arc/ back-arc Island arc

Age (Ma) ? ? ? 1882 to 1888

VMS potential Cu-Zn rich Zn-Cu rich Zn-Cu rich Zn-Pb-Cu rich c;; -- strike swings from northerly to westerly (Figure 2). No major D1 folds are found associated with this fabric which is inter­ preted to be related to originally east-trending folds in the area such as the Errington Lake Anti­ cline (Fox, 1976a and b; Reilly 1992) and the Magdalen Lake Syncline (Slimmon, 1993). D1 layer parallel shearing is repre­ sented by the Angeli's Island Shear Zone which is folded about the Crater Island Syn­ cline. A strong east-trending shear foliation is crenulated by a north-trending S2 fabric. Sinis­ tral shear sense is indicated from shear bands and rotation of fragments along the shear zone.

02 The Crater Island Assemblage is folded about the Winterton Island Anticline (Byers and Dahlstrom, 1954; Ayers et al. , 1991) and the Crater Island Syncline (Byers and Dahlstrom, 1954). These D2 structures are part of a system of predominantly north-trending, AM ISK LAKE upright, isoclinal folds in the I J Amisk Lake area. An axial pla­ kr, nar fabric is manifest as a dis­ continuously spaced or crenula­ tion cleavage defined by centi­ OrciovicicHl metre-scale micaceous lami­ ~ DoloMit e nae. Minor folds in the Crater Is­ land area plunge to the north Poleo pr o ter o zoic and to the south. Regional metamorphism, which is green­ D Felsic - rnte r l'lecHate Jntr usions -R- Fl Synclin e schist facies grade, was prob­ Dl Shear Zone ably initiated during D1 folding I./ /; j Porphyrit ic Hypo bys sol Roc k s and peaked during D2 folding - Synvol conic Mo f ;c Intr usions - 1- F2 Syncline (de Tombe, 1988; Ashton, 1990, 1992; Wilcox, 1990; ~ \./ elsh L o.k e AsseMbl oge Anticline Reilly, 1993; Slimmon, 1993). - · - F2 ~ \./est AMiSk As s eMbloge .,..,..,..,. D3 Shear Zo ne 03 Numerous D3 brittle-ductile ~ Mus keg Boy Asseribloge -- DS Fau lt shear zones transect the as­ semblage. In the south these S Croter lslo.nd Asser... blo.ge ~//. Su bo.eriol Volco.nis r... * subvertical structures trend ~ ~§ ~ ~ Sandy Boy Ass ef'lbl age ~""''\:: Surf Zone" north, and splay around the dominantly intrusive rocks of F:-:-:-j Bir c h Lake Asser1blage <* Frori Ayres et ol., 1991) Missi Island which behaved like Figure 2 - Generalized geology and structure of the Crater Island Assemblage. a mega-porphyroclast (Figure MLSZ=Mosher Lake Shear Zone; CbSZ==Comeback Bay Shear Zone; MCFZ=MacDon­ 2). A well-developed shear folia­ ald Creek Fault Zone; IFZ=lskwasoo Fault Zone; CBSZ==Cougal Bay Shear Zone; tion is defined by the alignment WISZ=Wilson Island Shear Zone; AISZ=Angell's Island Shear Zone; WCF=West Chan­ of micaceous minerals in mica nel Fault; WLSZ=Wolf Lake Shear Zone; DBS=Denare Beach Syncline; CIS=Crater schists, generally obscuring or Island Sync/fne; and WIA=Wintetton /stand Anticline. obliterating primary features. Ki- nematic indicators such as 01 The earliest recognizable fabric in the Crater Island shear bands, boudinaged and rotated quartz veins, Assemblage is an east-trending, bedding-parallel, rotated fragments, and porphyroclasts indicate sinis­ flattening fabric which is best developed in the An­ tral shear sense. Although shear-related stretching gell's Island area, south of Crater Island, where the

14 Summary of Investigations 1994 lineations are not well-developed, reverse-sinistral feldspar-phyric (trachytic) flows intercalated with het­ displacement has been documented along shear erolithic tuff breccias marks the transition from very zones throughout the Amisk Lake area (Stauffer and thinly bedded basaltic tuft at the top of the Crater Island Mukherjee, 1971 ; Wilcox, 1990; Reilly, 1993; Slim­ Assemblage to poorly sorted heterolithic andesitic tuft mon, 1993). Retrograde mineral assemblages com­ breccia at the base of the West Amisk Assemblage. posed of calcite±ankerite±chlorite±sericite±epidote This transitional unit roughly coincides with high-alu­ are associated with the shear zones and represent mina basalts of Fox (1976a). post-peak of metamorphism. The Crater Island Assemblage and the poorly exposed Two 03 shear zones have been distinguished, Muskeg Bay Assemblage, which is located on the west­ namely, Wilson Island and Cougal Bay shear ern mainland of Amisk Lake, are.composed of largely zones. Numerous smaller shears and splays are as­ tholeiitic island arc basalts which exhibit a gradational sociated. The geometry of the shear zones has contact with the overlying West Amisk Assemblage been described by Woodcock and Fischer (1986) as (Fox, 1976a and b; Walker and Watters, 1982; Watters a positive (reverse faulted) flower structure. The and Ashton, 1991 ; Reilly, 1992). Stratigraphic correla­ shear zones may converge at depth into a single tion is impeded by lake cover and the West Channel zone. Fault. Geochemical and isotopic studies which are in progress will improve our understanding of this relation­ The Crater Island Assemblage is separated from the ship. Sandy Bay Assemblage by the lskwasoo Fault Zone. This subvertical, north-trending structure ex­ tends form the Shield edge northward to Missi Is­ 4. Mineralization Potential land where it swings to the west. Deformation is dominantly brittle. The alignment of tectonic frag­ a) Volcanogenic Massive Sulphide Mineraliza- ments parallel to a penetrative fabric suggests that tion brittle deformation may have pre-dated the 03 duc­ tile deformation. Brittle-ductile shearing at Grant The application of whole-rock geochemistry to evaluat­ Bay, on the south shore of Missi Island, may repre­ ing tectonic environments is a useful tool for mineral ex­ sent reactivation along the lskwasoo Fault Zone. ploration (Fox 1976a and b; Swinden, 1991) and, as suggested by Syme and Bailes (1993), could be used 04 The Embury Lake Antiform, an open east-north­ profitably in the Flin Flon-Snow Lake greenstone belt. easterly-trending, easterly plunging flexural fold des­ ignated as 04, (Stauffer and Mukherjee, 1971), pas­ Large Zn-rich massive sulphide (VMS) deposits occur sively folds the 03 brittle-ductile shear zones in the in the Flin Flon region {Flin Flon and Callinan mines) north Missi Island area (Wilcox, 1990; Reilly, 1993; where they are hosted by tholeiitic island arc assem­ Slimmon, 1993). blages, whereas small Cu-rich deposits (Coronation, Birch, and Flexar mines) are hosted by tholeiitic back 05 Late stage faulting is interpreted from strong nega­ arc-ocean floor-type assemblages (Thomas, 1990). In tive topographic lineaments which transect the area the Snow Lake region, all VMS deposits are hosted by and displace lithological contacts. These lineaments a tholeiitic island arc assemblage (Bailes, 1988). The form a regional northeast and northwest conjugate Crater Island Assemblage has a largely tholeiitic island fault set (Reilly, 1992, 1993). arc tectonic setting (Fox, 1976a and b).

Other factors controlling VMS mineralization on a more 3. Contact Relationships: A Summary detailed scale must be considered:

The Crater Island Assemblage is in contact with the 1) Firstly, VMS deposits typically, if not exclusively, oc­ Sandy Bay Assemblage along the lskwasoo Fault Zone. cur within submarine volcanic environments (Lydon, The contact is exposed near the base of the Crater Is­ 1984). As was first suggested by Ayres (1978), the land Assemblage at lskwasoo Island where a distinct subaerial sequences of the Crater Island Assem­ tectonic breccia separates aphyric pillowed basalts of blage may be poor exploration targets for such de­ the Sandy Bay Assemblage to the east from interca­ posits. lated basaltic amygdaloidal pillowed flows and very thinly bedded tufts of the Crater Island Assemblage to 2) Secondly, the best documented VMS deposits the west. The breccia comprises poorly sorted basaltic within island arc assemblages occur at major strati­ fragments, averaging 30 x 1O cm in size, in a highly car­ graphic and compositional breaks in the volcanic se­ bonatized heteroltihic matrix of smaller angular frag­ quence, which are commonly marked by felsic vol­ ments of chert, quartz, carbonate, and sediment. canic units (Syme and Bailes, 1993). No felsic vol­ Deformation is dominantly brittle at the contact and canic rocks have been recognized in the Crater Is­ along subsidiary faults in adjacent rocks of the Crater Is­ land Assemblage to date. land Assemblage. 3) Thirdly, Syme and Bailes (1993) also note that most The Crater Island Assemblage has a gradational strati­ VMS deposits are associated with coarse volcani­ graphic contact with the overlying West Amisk Assem­ clastic rocks in the stratigraphic footwall. Volcaniclas­ blage. Southwest of Crater Island, a unit of coarse tic rocks of the Crater Island Assemblage are chlefly

Saskatchewan Geological Survey 15 tuff and fine lapilli tuft units, and coarser volcaniclas­ _ _ _ _ (1992): Geology of the Snake Rapids area: Up­ tic rocks such as tuft breccias are rare. date; in Summary of Investigations 1992, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 92-4, In summary, the Crater Island Assemblage was depos­ p97·113. ited in a tectonic environment similar to the large Zn­ Ayres, LO. (1978): A transition from subaqueous to subaerial rich VMS deposits, such as the Flin Flon mine in the eruptive environments in the middle Precambrian Amisk Flin Ron-Snow Lake greenstone belt. Detailed charac­ Group at Amisk Lake, Saskatchewan-Progress report; teristics of the Crater Island Assemblage, however, re­ Cent. Pree. Stud., 1978 Annual Rep., Univ. Man., p36-51 . veal features which are inconsistent with this type of VMS deposit, as may be borne out by the lack of _ _ _ _ (1980a): Preliminary stratigraphic investigation of known VMS deposits in the Crater Island Assemblage. the upper felsic-intermediate component of the Early Pro­ terozoic Amisk Group, Amisk Lake, Saskatchewan; Cent. Pree. Stud., 1980 Annual Rep., Univ. Man., p36·46. b) Gold Mineralization _ _ _ _ (1980b): Volcanology research; Cent. Pree. Stud., Two types of gold mineralization are documented in the 1980 Annual Rep., Univ. Man., p29-35. Amisk Lake area: _ ___ (1981): A subaqueous to subaerial transition zone in the early Proterozoic metavolcanic sequence, Amisk 1) The Laural Lake Au-Ag deposit, situated in the north­ Lake, Saskatchewan; Cent. Pree. Stud., 1981 Annual west part of Missi Island, is an epithermal-type de­ Rep., Univ. Man., p49-61 . posit hosted by felsic volcanic rocks (Ansdell and Kyser, 1991; Harper, 1993). Mineralization predates Ayres, LD., Van Wagoner, N.A., and Ferreira, W .S. (1991): Vo­ regional metamorphism and the major deformation luminous shallow-water to emergent phreatomagmatic ba­ events in the Amisk Lake area. saltic volcaniclastic rocks, Proterozoic (=1886 Ma) Amisk Lake composite volcano, Flin Ron greenstone belt, Can­ 2) The majority of gold occurrences in the region, in­ ada; in Sedimentation in Volcanic Settings, SEPM Spec. Publ. No. 45, p175·187. cluding the Graham, Monarch-Prince Albert, and Black Diamond deposits, are mesothermal deposits Ayres, LO., Van Wagoner, N.A., and Van Wagoner S. (1981): hosted by 03 brittle-ductile shear zones, such as Physical volcanology of the Amisk Lake volcano; in Sum­ the West Channel Fault (Ansdell and Kyser, 1992; mary of Investigations 1981, Saskatchewan Geological Sur­ Reilly, 1992, 1993). Some of the shear-zone hosted vey, Sask. Miner. Resour., Misc. Rep. 81·4, p47·51. deposits may represent remobilization of early miner­ alization (Reilly, 1993; Harper, 1993). To date, sev­ Bailes, A.H. (1988): Chisel-Morgan lakes project; in Report of Field Activities, 1988, Man. Energy Mines, Min. Div., p53· eral gold showings have been found in the Crater Is­ 61. land Assemblage. Recognition of major shear zones and subsidiary splays serve as exploration targets Byers, A.A. and Dahlstrom, C.D.A. (1954): Geology and min· for structurally controlled mineralization. The flower eral deposits of the Amisk-Wildnest lakes area, 63L-9, structure geometry of these structures and the possi­ 63L-16, Saskatchewan; Sask. Dep. Miner. Resour., Rep. bility of convergence to a larger single shear zone 14, 177p. at depth may enhance the potential for gold minerali­ zation. de Tombe, J. (1988): The metamorphic stability fields of the Welsh Lake Area in east-central Saskatchewan; unpubl. B.Sc. thesis, Queen's Univ., 46p.

5. Acknowledgments Ferreira, W.S. (1981 ): An example of a volcanic subaerial and surf environment in the middle Precambrian Amisk Group Field and office assistance was provided by Cliff Rever­ at Amisk Lake, Saskatchewan-A progress report; Cent. ing. Field visits by Richard Stern, Steve Lucas, and Pree. Stud., 1981 Annual Rep., Univ. Man., p47-59. Dave Thomas proved helpful. An early version of this manuscript was critically reviewed by Bob Macdonald _ _ __ (1984): A physical comparison of subaerial and and Ken Ashton. subaqueous eruptive environments in the Proterozoic Amisk Group, Saskatchewan, Canada: unpubl. M.Sc. thesis, Univ. Man., 199p. 6. References Fox, J.S. (1976a): Some comments on volcanic stratigraphy Ansdell, K.M. and Kyser T.K. (1991): The geochemistry and and economic potential of the West Amisk Lake area, Sas­ fluid history of the Proterozoic Laurel Lake Au-Ag deposit, katchewan; Sask. Resear. Coun., Circ. 9, 30p. Flin Flon greenstone belt; Can. J. Earth Sci., v28, p155- 171. ____ (1976b): Volcanic stratigraphy and mineralization in the Amisk Group; Geol. Assoc. Can./Min. Assoc. Can., ____ (1992): Mesothermal Gold Mineralization in a Pro­ Jt. Annu. Meet., Edmonton, Prog. Abstr., v1, p72. terozoic Greenstone Belt: Western Flin Flon Domain, Sas· katchewan, Canada; Econ. Geol., v87, p1496-1524. Gaskarth, J.W. and Parslow, G.R. (1987): Proterozoic volcan­ ism in the Flin Flon greenstone belt, east-central Saskatch­ Ashton, K.E. (1990): Geology of the Snake Rapids area, Flin ewan, Canada; Geol. Soc., Spec. Publ. 33, p183-200. Flon Domain (parts of NTS 63L-9 and -10); in Summary of Investigations 1990, Saskatchewan Geological Survey, Harper, C.T. (1993): Intrusive and extrusive rocks of the west­ Sask. Energy Mines, Misc. Rep. 90-4, p4-12. ern part of Missi Island, Amisk Lake; In Summary of lnvesti· gations 1993, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 93·4, p30-39.

16 Summary of Investigations 1994 Heaman, L.M., Ashton, K.E., Reilly, B.A., Sibbald, T.1.1., Stern, A.A., Syme, E.C. , and Lucas, S.B. (in press a): MOAB· Slimmon. W.L., and Thomas, D.J. (1993): 1992-1993 U-Pb and OJB-like volcanism in the Flin Aon Belt, Canada: Tap­ geochronological investigations in the Trans-Hudson Oro­ ping heterogeneities in the 1 .9 Ga sub-oceanic mantle; gen, Saskatchewan; in Summary of Investigations 1993, Geochem. Cosmochim. Acta. Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 93-4, p109-111. Stem, A.A., Syme, E.C., and Bailes, A.H. (in press b): Paleo­ proterozic (1.90 to 1.86 Ga) volcanism in the Flin Flon Lydon, J.W. (1984): Volcanogenic massive sulphide deposits Belt, Trans-Hudson Orogen, Canada; Contrib. Mineral. Pet· Part 1: A descriptive model; Geosci. Can., v11, p195-202. rot.

Parslow, G.R. and Gaskarth, J.W. (1984): Geochemistry of the Swinden, H.S. (1991 ): Paleotectonic settings of volcanogenic east Amisk area; Sask. Energy Mines, Open File Rep. 84· massive sulphide deposits in the Dunnage zone, New­ 23, 156p. foundland Appalachians; Can. Min. Met. Bull., v83, no934, p59-69. ___ _ _ (1988): Proterozoic rocks of east-central Sask· atchewan: Geochemistry, structure, and mineralization con­ Syme, E.C. and Bailes, A.H. (1993): Stratigraphic and tectonic trols; in Summary of Investigations 1988, Saskatchewan setting of Early Proterozoic volcanogenic massive sulphide Geological Survey, Sask. Energy Mines, Misc. Rep. 88·4, deposits, Flin Flon, Manitoba; Econ. Geol., vaa, p566-589. p127-139. Thomas, D.J. (1990): New perspectives of the Amisk Group Reilly, B.A. (1992): Revision bedrock geological mapping, and regional metallogeny, Douglas Lake-Phantom Lake Neagle Lake-Errington Lake area (parts of NTS 63L·9 and area; in Summary of Investigations 1990, Saskatchewan -16); in Summary of Investigations 1992, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 90-4, Geological Survey, Sask. Energy Mines, Misc. Rep. 92-4, p13-20. p16-22. Van Wagoner, N., Moon, N., Ayres, L.D., Tange, R., and Car­ ___ _ {1993): Revision bedrock geological mapping of swell, A. (1982): Preliminary results of rheological model· the northwest Amisk Lake area (parts of NTS 63L-9 and ing of a Proterozoic volcano and Earth; Cent. Pree. Stud., -16); in Summary of Investigations 1993, Saskatchewan 1982 Annual Rep., Univ. Man. , p128·150. Geological Survey, Sask. Energy Mines, Misc. Rep. 93-4, p12·20. Van Wagoner, N. and Van Wagoner, S. (1987): Shallow water volcanism and sedimentation in a portion of the Flin Flon­ Reilly, B.A., Slimmon, W.L., Harper, C.T., Ashton, K.E., Snow Lake greenstone belt: A preliminary report; Cent. Heaman, L.M., and Watters, B.R. (in press): Contrasting Pree. Stud., 1987 Annual Rep., Univ. Man., p71 ·88. lithotectonic assemblages from the western Flin Aon Do· main; LITHOPROBE, Trans-Hudson Orogen Transect Re­ Van Wagoner, S. ( 1982): A probable storm-generated turbidite port. association-Proterozoic Flin Flon-Snow Lake greenstone belt; Cent. Pree. Stud., 1982 Annual Rep., Univ. Man., Slimmon, W.L. (1991a): Revision bedrock geological mapping, p115-1 27. Table Lake area (part of NTS 63L·9); in Summary of Inves­ tigations 1991, Saskatchewan Geological Survey, Sask. Walker. D. and Watters. B.R. (1982): Geochemistry of metavol· Energy Mines, Misc. Rep. 91-4, p16·20. canic rocks, Amisk Lake West area; in Summary of lnvesti· gations 1982, Saskatchewan Geological Survey, Sask. _ _ _ _ (1991b): Revision bedrock geological mapping, Energy Mines, Misc. Rep. 82-4, p24-30. Table Lake area (part of NTS 63L-9); with Summary of In· vestigations 1991, Saskatchewan Geological Survey, Watters, B.R. and Ashton, K.E. (1991): Geochemistry and tec­ Sask. Energy Mines, Misc . Rep. 91-4, preliminary map at tonic setting of metabasaltic rocks from the Snake Rapids 1:12 500 scale. area, Flin Fion Domain; in Summary of Investigations 1991 , Saskatchewan Geological Survey, Sask. Energy _ _ __ (1993): Bedrock geological mapping of the Come­ Mines, Misc. Rep. 91-4, p130-134. back Bay area, Amisk Lake (part of NTS 63L·9 and -16); in Summary of Investigations 1993, Saskatchewan Geologi­ Watters, B.R., Dostal, J., Slimmon, W.L., and Thomas, D.J. (in cal Survey, Sask. Energy Mines, Misc. Rep. 93-4, p21-29. press): Geochemistry, petrogenesis, and tectonic setting of Early Proterozoic volcanic rocks of the Flin Flon Domain, Stauffer, M.A. and Mukherjee, A.C. (1971): Superimposed de· Saskatchewan {Canada) Oceanic back-arc volcanism; N. formations ;n the Missi metasedimentary rocks near Flin Jb. Miner. Mh. Flon, Manitoba; Can. J. Earth Sci., v12, p2012·2035. Wilcox, K.H. (1990): Geology of the Amisk-Welsh lakes area, Stem, A.A. and Lucas, S.B. (in press): U-Pb zircon age con­ Saskatchewan; unpubl. M.Sc. thesis, Univ. Calgary, 245p. straints on the early tectonic history of the Flin Flon accre­ tionary collage, Saskatchewan; in Radiogenic Age and Woodcock, N.H. and Fischer, M. (1 986): Strike-slip duplexes; Isotopic Studies: Report 8, Geol. Surv. Can., Pap. 94-2. J. Struc. Geol., vs. no7, p725-735.

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