Saskatchewan Geological Survey 1 Summary of Investigations 2002, Volume 2

A Geological Transect Across the Southwestern Peter Lake Domain,Saskatchewan

Ralf O. Maxeiner and Rebecca Hunter 1

Maxeiner, R.O. and Hunter, R. (2002): A geological transect across the southwestern Peter Lake Domain, Saskatchewan; inSummary of Investigations 2002, Volume 2, Saskatchewan Geological Survey, Sask. Industry Resources, Misc. Rep. 2002-4.2,CD-ROM, Paper A-3, 24p.

AbstractThe largely Archean Peter Lake Domain is wedged between the Wollaston Domain to the northwest and thePaleoproterozoic Wathaman Domain to the southeast, bounded in part by the Needle Falls Shear Zone and theParker Lake Shear Zone, respectively. Its perceived high platinum group element potential and ambiguousgeological history and setting prompted the Saskatchewan Geological Survey to initiate a detailed three-yearmapping project. Historically, the domain has been subdivided into three main components: the Peter LakeComplex, its high-strain equivalents called the Parker Lake Gneisses, and a low-grade sedimentary succession, theCampbell River Group. In the first year of the project, a 40 km long and 10 to 15 km wide transect flankingHighway 905 was mapped between Courtenay Lake and the Wathaman River. The poorly exposed northern half ofthe map area comprises large intrusions of massive to weakly foliated syenogranite, part of which is fluorite-bearing, and a dioritic to gabbroic suite. The southern half of the domain is better exposed and is underlain bymassive to mylonitic, mafic to felsic plutonic rocks, including leucogabbroic to anorthositic, gabbroic, and dioriticsuites, as well as younger granodioritic, monzonitic, and granitic intrusive suites. The Love Lake leucogabbrocontains rare examples of well preserved primary igneous layering. Locally abundant fine-grained mafic xenolithsin the pluton have a tectonic foliation predating the fabric in the host. Several slivers of upper amphibolite faciesmigmatitic supracrustal rocks are between Peter Lake and the Wathaman River, as well as a 0.2 to 1.5 km outlier oflower amphibolite facies Campbell River Group quartzite and argillite containing well preserved primarysedimentary structures including crossbedding, and ball-and-pillow structures. The structural history included atleast four ductile deformational events, two main regional metamorphic events, and late brittle faulting.

Several outcrops contain disseminated iron sulphides, chalcopyrite, and rare azurite. Geochemical analyses of grabsamples have not returned significant values of gold, copper, and/or platinum group elements.

Keywords: anorthosite, Campbell River Group, copper, geochemistry, geochronology, Hearne Province,leucogabbro, Neoarchean, northern Saskatchewan, Parker Lake Gneisses, Peter Lake Complex, Peter LakeDomain, platinum group elements, Wathaman Batholith, Wollaston Domain.

1. Introduction

According to Hulbert, (1989, p60-61), the “Peter Lake Complex is the largest concentration of mafic rocks inSaskatchewan and, after the Duluth Complex, it is the second largest mafic intrusion complex in NorthAmerica … The immense size of this complex and the presence of significant PGE mineralization suggest that thePeter Lake Complex has substantial PGE potential …”.

The Peter Lake Domain (Figure 1) is wedged between the Wollaston Domain to the northwest and thePaleoproterozoic Wathaman Domain to the southeast, bounded in part by the Needle Falls Shear Zone (Money,1965; Stauffer and Lewry, 1993) and the Parker Lake Shear Zone (Ray, 1975; Lafrance and Varga, 1996),respectively. Its unusual lithological character and partly fault-bounded nature were reasons to give it separatedomain status (Macdonald and Thomas, 1983; Saskatchewan Geological Survey, 1994), although many workersconsider it to represent the southeastern margin of the largely Archean Hearne Province (e.g., Corrigan, 2001).

Its perceived high platinum group element (PGE) potential and ambiguous geological history and setting promptedthe Saskatchewan Geological Survey to initiate a detailed three-year mapping project. Selected areas or transects

1 Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2.

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have been chosen for detailed1:20 000 scale frameworkmapping. In this first year of theproject, a 40 km long and 10 to15 km wide transect alongHighway 905 was mappedbetween Courtenay Lake and theWathaman River, stretchingacross the Peter Lake Domainand extending into the boundingWollaston and Wathamandomains. Future work willinvolve transects along ReindeerLake and through the centralparts of the domain. Supportinggeoscience will includegeochemical, petrological, andgeochronological studies todetermine protoliths, tectonicsettings, and age relationships ofvarious rocks. This work will alsoinclude an evaluation of themineral potential of the domain.

Tyrell and Dowling (1896) werethe first to report on the geology.The Spalding Lake sheet (part ofNTS 64E-SW) was later mappedby Weeks (1941) for theGeological Survey of Canada andby Lewry et al. (1980) for theSaskatchewan GeologicalSurvey. Other mapping in thelarger Peter Lake Domain, mostlyat scales of 1:63,360 (1 inch tothe mile) and 1:100 000, issummarized in Figure 2. Themost recent of this has beencarried out by the GeologicalSurvey of Canada (Corrigan etal., 2000; Corrigan, 2001).

2. Regional GeologicalFramework

The domain is largely Archeanand comprises the Peter Lake

Complex (Ray and Wanless, 1980), Swan River Complex (Stauffer et al., 1981; Corrigan, 2001), Parker LakeGneisses (Ray, 1975), and Campbell River Group (Lewry, 1976; Lewry et al., 1980). The southwestern part of thedomain is bounded by the Needle Falls and Parker Lake shear zones, however, these die out towards the northeast.On Reindeer Lake it is intruded along its southern flank by partly megacrystic granitoid plutons of the 1.86 GaWathaman Batholith (Corrigan et al., 2000; 2001; Corrigan, 2001). In the Cook Lake area, approximately 30 km tothe northeast of Highway 905, the northern flank of the domain is unconformably overlain by feldspathic psammite,cobble conglomerate, or mafic volcanic rocks of the Paleoproterozoic Courtenay Lake Formation of the WollastonDomain (Delaney et al., 1997; MacNeil et al., 1997).

The Peter Lake Complex, which represents the largest component of the Peter Lake Domain, is a veryheterogeneous, predominantly plutonic assemblage. It ranges in composition from ultramafic to felsic, and instructure from massive to mylonitic. It has been metamorphosed to upper amphibolite facies causing anatexis, yetlocally has well preserved primary igneous layering.

On Reindeer Lake, Corrigan (2001) identified minor units of mafic metavolcanic rocks, which he interpreted as theoldest component of the Peter Lake Complex. This is consistent with observations by Lewry et al. (1980), who

Figure 1 - Main subdivisions of the Peter Lake Domain.

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described remnants of layered pyroclastic or volcaniclastic rocks in the dioritic to gabbroic units of the Peter LakeComplex.

Figure 3 and Table 1 summarize historical geochronological data for the Peter Lake Domain. Major felsic plutonismin the Peter Lake Complex is constrained to 2580 to 2560 Ma (Ray and Wanless, 1980; Bickford et al., 1986;Annesley et al., 1992; Rayner et al., in review).

The Lueaza River granitoid rocks (i.e., map unit 4 of Stauffer et al., 1981) represent a large component of the PeterLake Complex on Reindeer Lake (Corrigan et al., 2000). They are composed of migmatized plutonic andsedimentary rocks, as well as non-migmatized strongly foliated and recrystallized granitoid rocks and minorsupracrustal rocks. A sample of pink granitic gneiss intruding older grey gneiss from the Lueaza River granitoids onnorthwestern Reindeer Lake yielded rather complex results (Bickford et al., 2002; Rayner et al., in review). Itprovided U-Pb zircon age of 2629 ±10 Ma, which is the oldest age for the domain to date. The sample also hasevidence for a second generation of zircon growth between 2590 to 2560 Ma, as well as a lower intercept age of1800 Ma.

Corrigan (2001) identified the ‘Swan River Complex’, originally named ‘Swan River gabbro’ by Stauffer et al.(1981), as a separate suite that intruded the Peter Lake Complex (Corrigan et al., 2000). It also includes alkalineintrusives such as the Patterson Island Pluton (MacDougall, 1987). The complex is characterized by layered mafic,ultramafic and intermediate rocks including pyroxenite, olivine gabbro, leucogabbro, anorthosite, and diorite, all ofwhich contain primary igneous minerals and have been only weakly metamorphosed to uppermost greenschistfacies conditions. A 2562 ±4 Ma U-Pb zircon age (Corrigan et al., 2001) from the Swan River Complex onReindeer Lake is the only age date for intermediate to mafic plutonism in the Peter Lake Domain.

The Campbell River Group (Lewry, 1976; Lewry et al., 1980; MacDougall, 1987) forms a narrow upper greenschistto lower amphibolite facies supracrustal belt that lies within a northeast-trending asymmetrical synform northwestof Spalding Lake. This low-grade succession includes slate, phyllite, sulphide-bearing argillite, quartz arenite, and

Figure 2 - Summary of previous mapping in the Peter Lake Domain.

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minor mafic volcanic rocks. Its inferred age is Archean, based on the presence of xenoliths that resemble CampbellRiver Group lithologies in neighbouring diorite of the Peter Lake Complex (Lewry et al., 1980; Macdonald andThomas, 1983).

A more detailed study of the Campbell River Group (MacDougall, 1987) distinguished additional units of bandedcalc-silicate quartzite, calc-pelite, anthophyllite amphibolite, calc-silicate amphibolite, and amphibolitic epiclasticrocks, along with several intrusive lamprophyres of mixed composition and a quartz diorite unit. A westernextension of the Campbell River Group, comprising quartzite, black siltstone/argillite and pink arkose containingdetrital grains of blue quartz, was noted by MacDougall (1988) along Highway 905.

The Parker Lake Gneisses (Ray, 1975) are confined to the southwestern end of the domain, where they largelyparallel the Needle Falls and Parker Lake shear zones. They are strongly foliated and sheared mafic to felsic rocksthat are interpreted as sheared equivalents of the Peter Lake Complex (Lewry et al., 1980; Macdonald and Thomas,1983). A mylonitic megacrystic quartz monzonite of the Parker Lake Gneisses provided a U-Pb zircon age of 2566±8 Ma (Rayner et al., in review), similar to the age of felsic plutonism for the Peter Lake Complex (Figure 3, Table1).

A quartz monzonite, collected southwest of Peter Lake in the centre of the domain, yielded a titanite age of 2529±4 Ma. The titanite is reported to be igneous looking (Annesley et al., 1992), but is here speculated to represent alate Archean high-grade metamorphic event.

Figure 3 - Summary of previous U-Pb geochronological results for the Peter Lake Domain.

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Table 1 - Summary of previous U-Pb geochronological results for the Peter Lake Domain. PLC, Peter Lake Complex; WB,Wathaman Batholith in the Peter Lake Domain; SRC, Swan River Complex; CLF, Courtenay Lake Formation; and PLG,Parker Lake Gneisses.

Lithology NTS UTM-E UTM-NU-P age (Ma)zircon

U-P age (Ma)other Reference

Pink granitic gneiss, PLCsouthwest of Crane Island, Reindeer Lake

64E-16 1860 ±5 Bickford et al. (1986)

Feaviour Peninsula granite, WBFeaviour Peninsula, Reindeer Lake

64E-16 662210 6418525 1861 +3/-2 Corrigan et al. (2001)

Gabbro pegmatite, SRCsouthwest of Crane Island, Reindeer Lake

64E-16 1908 ±27 Bickford et al. (1987)

Mylonitic quartzofeldspathic gneiss, CLFWollaston Domain, Courtenay Lake

64E-5 564500 6363520 2076 ±3 1753 ±40 (garnet) Annesley et al. (1992)

Foliated syenogranite, PLCnear Courtenay Lake microwave tower

64E-5 562040 6359525 2086 +52/-8 1809 ±15 (titanite) Annesley et al. (1992)

Weakly deformed granite, PLCHighway 905, near kilometre 120???

64E-4 2476 ±92514 ±82520 ±10

Van Schmus et al.(1987)

Quartz diorite, PLCTaylor Lake

74H-1 2538 ±10 Ray and Wanless (1980)

Pink granitic gneiss, PLCsouthwest of Crane Island, Reindeer Lake

64E-16 2556 ±22 Bickford et al. (1987)

Swan River gabbro, SRCMcLean Bay, Reindeer Lake

64E-10 660150 6412775 2562 ±4 1830 lower intercept Corrigan et al. (2001)

Quartz monzonite, PLCHighway 905, near kilometre 120

64E-4 564745 6337240 2566 ±2 2529 ±4 (titanite) Annesley et al. (1992)

Mylonitic megacrystic granodiorite, PLGHighway 905, near kilometre 108.5

64E-4 2566 ±8 Rayner et al. (in review)

Pink granitoid gneiss, PLCsouthwest of Crane Island, Reindeer Lake

64E-16 2580 ±4 2566 ±4 overgrowth Rayner et al. (in review)

Fine-grained foliated gneiss, PLCCombe Lake

64E-5 2580 ±5 Rayner et al. (in review)

Grey megacrystic gneiss, PLCsouthwest of Crane Island, Reindeer Lake

64E-16 2582 ±19 Bickford et al. (1987)

Pink granitic gneiss, PLCsouthwest of Crane Island, Reindeer Lake

64E-16 2629 ±10 2566 ±4 overgrowth Rayner et al. (in review)

Two ages from the northern margin of the domain, one from within and another from approximately 400 metres tothe northwest of its boundary with the Wollaston Domain, provide age of 2086 +52/-8 Ma and 2076 ±3 Ma,respectively. The latter sample, a garnet-bearing mylonitic quartzofeldspathic gneiss that was interpreted as beingintrusive in origin, yielded an age identical within error to the 2075 ±2 Ma quartz-feldspar porphyry of the CookLake area (Ansdell et al., 2000). The latter high-level intrusive into the Courtenay Lake Formation was thought torecord the initiation of rifting along the southeastern edge of the Hearne craton.

A feldspar megacrystic syenogranite from the southern margin of the Peter Lake Domain on Reindeer Lake yieldeda U-Pb zircon age of 1861 +3/-2 and was interpreted to belong to the Wathaman Batholith suite (Corrigan et al.,2001). It provides clear evidence that the southern margin of the domain is intruded by the Wathaman Batholith.

Titanite and lower intercept ages for the felsic granitoid rocks vary between 1830 and 1800 Ma, probably a result ofthe thermotectonic overprint produced by the Trans-Hudson Orogeny. Growth of titanite suggests that loweramphibolite facies conditions must have been reached during this event. However, Rayner et al. (in review) foundno evidence of Paleoproterozoic zircon growth in their Peter Lake Domain samples, suggesting that metamorphicgrades remained below upper amphibolite facies conditions.

3. Results From Field Work

The transect was mapped by a five-person crew between the beginning of June and the end of August. Access wasprovided by Highway 905, and from there by traversing on foot, as well as utilizing canoes and inflatable boats.

The northern 20 km of the transect, between Courtenay Lake and Peter Lake, is characterized by exceptionally poorbedrock exposure and extensive, almost continuous glacial and fluvioglacial deposits. Traversing is easy, as theforest is open and dominated by >30 year old pine trees. A forest fire that burned for a few days at the end of Junedestroyed over one thousand hectares of forest east and northeast of Combe Lake.

The southern 20 km of the transect, between Peter Lake and the Wathaman River has a higher proportion ofexposure, with moderate amounts of glacial and fluvioglacial overburden. Here, however, the forest was burnt in ahuge fire in 1981. The deadfall and new growth made traversing on foot very difficult and slow.

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Several southwest-trending eskers transect the map sheet. The biggest intersects the south-central part of Peter Lake,another is north of Findlay Lake, and a third is half way between Warner and Robson lakes. Most glacial striationsand chatter marks are oriented between 218º and 222º. An older set of glacial striae at 170º to 190º was observed inseveral locations.

a) Peter Lake Domain

The area can also be geologically subdivided into northern and southern components. The poorly exposed northernpart is dominated by coarse-grained, massive to weakly foliated syenogranite and leucocratic syenogranite, withminor diorite, gabbro, and late mafic dykes (Figure 4).

The preliminary 1:20 000 scale map of the southern part of the transect displays a complex plutonic terraincharacterized by highly flattened units of quartz diorite to gabbro, monzonite to granite, minor migmatiticsupracrustal screens, and an outlier of the low-grade Campbell River Group (Figure 4). There is no obvious changein rock types, proportion of rock types, or degree of deformation between Peter Lake and the Wathaman River,although the strain generally increases from north to south. Belts of intense deformation and mylonitization werealso observed just south of Peter Lake.

All plutons are highly flattened at map scale. Strain is heterogeneous and generally restricted to the marginal zonesof the plutons, so that large bodies may appear unstrained and massive internally, but have mylonitized margins.The margins are also commonly characterized by complex intrusive relationships, which were transposed duringshearing leading to layered or ‘gneissic’ outcrop appearances. Due to the scale of mapping, however, we were ableto distinguish individual rock types or combine outcrops of multiple lithologies into distinct units. Therefore, thepreviously used distinction between rocks of the Peter Lake Complex and Parker Lake Gneisses (Ray, 1975; Lewryet al. 1980) was revised. Most intrusive rocks described below form part of the Peter Lake Complex.

All rock names for intrusive rocks follow Streckeisen’s (1976) recommendations on the classification of plutonicrocks. Mineral percentages were estimated in the field and assigned sample names and were later verified with thehelp of a petrographic microscope. Classification of clastic sedimentary rocks follows the recommendations ofMaxeiner et al. (1999). The prefix ‘meta-’ is not used, as all of the rocks have been metamorphosed at greenschist toamphibolite facies. Only selected units and important observations and relationships are described in detail in thispaper. For comprehensive and systematic descriptions of all units, the reader is referred to the legends of theaccompanying maps.

Love Lake Leucogabbro

One of the largest mafic intrusions between Peter Lake and Love Lake is the Love Lake Leucogabbro2. This ovoidpluton was mapped over an area of about 5 km by 10 km, but based on aeromagnetic data and previous mapping itextends further east for at least an additional 10 km. On the basis of published descriptions, Love Lake Leucogabbroappears similar to the 2.56 Ga Swan River Complex on Reindeer Lake (Corrigan et al., 2000). The Swan RiverComplex, however, intrudes the surrounding granitoid rocks, whereas the Love Lake Leucogabbro appears topredate surrounding granitic rocks in the Peter Lake area.

The pluton comprises many different phases, but is dominated by leucogabbro. Minor components includepyroxenite, melagabbro, gabbro, gabbronorite, olivine gabbro, anorthosite, and diorite, as well as microgabbro andmicrodiorite.

The main leucogabbroic phase of the pluton is medium grained, weathers a characteristic light bluish grey and isdark grey on fresh surface. It comprises plagioclase, amphibole, relict clinopyroxene, biotite, magnetite, pyrite, andhematite. Mafic mineral content generally varies between 15 and 25%, with magnetite typically accounting for atleast 5% of that. The bluish weathering colour is due to the Ca-rich nature of the plagioclase (labradorite).Amphibole occurs both as relict igneous grains and as secondary metamorphic minerals replacing clinopyroxeneand primary hornblende. Magnetite is commonly hematized and pyrite is ubiquitous, but rarely exceeds 1%.

Primary igneous layering (Figure 5) was observed at only one locality, close to the northern margin of the pluton(UTM-E: 565533; UTM-N: 63403983), where layers of anorthosite and gabbro alternate at 1 to 5 cm intervals. Atseveral places, the gabbro contains abundant inclusions, which vary in diameter from decimetre to metre scale, inshape from angular to rounded, and in composition from mafic to ultramafic (Figure 6). Most of the inclusions arefine grained, locally feldspar porphyritic and some are possibly amygdaloidal. They have sharp contacts and some

2 Informal names appear in italics where first mentioned; the italics are subsequently dropped.3 All UTM coordinates in this paper are given in NAD83.

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Figure 4 - Simplified geological map for the Peter Lake transect; references U-Pb age date locations can be found in Table 1;numbered locations refer to mineral occurrences described in text.

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are fractured and invaded by the leucogabbroic host.Some of the more ultramafic inclusions are rounded anddisplay reaction rims, possibly indicating that they havebeen within the melt for a longer period of time (Figure7). Based on these observations, the inclusions areinterpreted as xenoliths rather than autoliths.

One of the gabbroic units near the southern margin ofthe pluton contains primary orthopyroxene,clinopyroxene, and minor biotite and can be properlyclassified as a gabbronorite. Most of the orthopyroxenegrains are rimmed by cummingtonite, as a result ofsubsequent amphibolite facies metamorphism.

To the north, the Love Lake Leucogabbro is intruded bya large syenogranite pluton named the Robinson LakeMonzogranite (Ray, 1980). Along Highway 905, theLove Lake Leucogabbro is in contact to the north withfine-grained porphyritic volcanic or subvolcanic maficrocks (unit Mv), which it probably intruded.

Deformation is generally very weak. Most exposures ofthe leucogabbro are massive, but a weak flatteningfabric defined by the alignment of mafic mineralslocally trends east-west, parallel to the main regionalfoliation. Igneous layering, observed at one locality,also trends parallel to the main foliation. Some of thefine-grained mafic xenoliths appear to have a tectonicfabric, which predated emplacement of the pluton(Figure 6). Eastward towards the Johnson River, thepluton is cut by a pink leucogranite sheet, which has anortherly to northeasterly trend and foliation. Smallshear zones within the Love Lake Leucogabbro alsohave northeasterly strike.

Warner Lake Gabbroic Suite

Several highly flattened composite intrusions varying incomposition from pyroxenite to diorite are exposedbetween the Love Lake Leucogabbro and the ParkerLake Shear Zone. There are at least five separate dioriticto gabbroic belts, which are 200 to 400 m thick andcontinuous for more than 10 km along strike. These, andthe Love Lake Leucogabbro, may have originally allbeen part of the same intrusive complex, which waslater invaded by granitoid magmas and subsequentlydeformed.

These intrusions are dominated by fine- to medium-grained ‘salt and pepper’ diorite, which is massive tostrongly foliated and locally mylonitic. Mainconstituents are plagioclase, hornblende, biotite,epidote, and magnetite, with minor quartz, titanite,sulphides, and carbonate. The mafic mineral contentvaries between 20 and 35%. The gabbroic rocks aresimilar to the diorite, but typically have a mafic mineralcontent of around 50%. In contrast to the Love LakeLeucogabbro, plagioclase in these intermediate to maficrocks is generally white weathering likely due to a lowAn-content (oligoclase and andesine).

The magnetite content of the diorite and gabbro ishighly variable. Locally, they contain up to 5%magnetite and have magnetic susceptibilities similar to

Figure 5 - Primary igneous layering in the Love LakeLeucogabbro; alternating layers of anorthosite (white) andgabbro (dark grey); UTM-E: 565533, UTM-N: 6340398.

Figure 6 - Angular to subangular inclusions in leucogabbroof the Love Lake Leucogabbro; note the differingcomposition, texture, and foliations in these xenoliths;UTM-E: 563398; UTM-N: 6336046.

Figure 7 - Round ultramafic xenolith displaying a reactionrim at contact with the host leucogabbro; Love LakeLeucogabbro; UTM-E: 563398; UTM-N: 6336046.

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those of the Love Lake Leucogabbro (i.e., 30 to 100x10-3 SI); more typically they have magneticsusceptibilities of between 0.5 and 1 (x10-3 SI).

The Warner Lake gabbroic suite is more deformed thanthe Love Lake Leucogabbro. The units are generallystrongly flattened, most minerals are recrystallized, andprimary textures are rarely preserved. Xenoliths of fine-grained amphibolite and psammitic rocks are locallyabundant.

One of several examples of primary igneous layering isexposed at kilometre 118 on the eastern side ofHighway 905 (UTM-E: 565864; UTM-N: 6335350).Layering is on a scale of 1 to 5 cm and alternatesbetween thinner anorthositic to dioritic and thickergabbroic layers (Figure 8). In another part of the sameoutcrop, the gabbro is cut by late anorthositic veins(Figure 9).

Most of the ultramafic rocks are highly recrystallizedand largely amphibolitized. Some relict igneousminerals have been locally preserved; varieties ofultramafic rocks include olivine websterite andclinopyroxenite.

Combe Lake Dioritic Suite

Homogeneous, massive to weakly foliated dioritic togabbroic intrusions occur in an 8 km long and 2 kmwide belt that stretches along the Johnson River andthrough the central part of Combe Lake. They aretypically medium grained, black and white weathering,yellowish to brownish grey on fresh surface, and friabledue to sericitized plagioclase. Sodic plagioclase andhornblende dominate; minor constituents includeepidote, titanite, biotite, and opaque minerals. Locally,there are gabbroic to dioritic pegmatite phases. Themagnetic susceptibility is significantly lower than in theLove Lake Leucogabbro, typically varying between 0.3and 0.7 (x10-3 SI).

Locally, the gabbroic rocks grade into amphibolitizedpyroxenite. No relict pyroxene or olivine were observed.Intrusive relationships between the dioritic and gabbroic phases are generally obscured, but in several outcrops theyappear gradational into one another. No primary features were observed.

The Combe Lake dioritic suite is cut by leucogranite sheets. Near the southern boundary, are two generations ofmafic dykes, a feldspar and hornblende porphyritic set and a later aphanitic set. Both predate the maindeformational event and are transposed. Some of these dykes have very high magnetic susceptibilities (e.g., 40x10-3

SI).

Gneissic Quartz Diorite and Granodiorite

North of the Wathaman River is an approximately 3 km wide belt of intensely foliated and in part mylonitizedorthogneisses. Outcrops in this belt generally contain multiple transposed rock types, including diorite, quartzdiorite, granodiorite, and rare gabbro. There are also some fine-grained dark grey amphibolitic to biotiticcomponents that may be of supracrustal origin.

At the current scale of mapping, these orthogneisses were treated as a composite unit. They are the only rocks thatappear similar to the ‘Parker Lake Gneisses’ (Ray, 1975).

Figure 8 - Primary igneous layering (262/85) in a gabbroicunit that transects Highway 905 at kilometre 118; UTM-E:565864; UTM-N: 6335350.

Figure 9 - Intrusion breccia with late-stage anorthositicveins cutting massive homogeneous gabbro; eastern side ofHighway 905 at kilometre 118; UTM-E: 565864; UTM-N:6335350.

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Most of the rocks within this belt are heterogeneous andstrongly variable in colour, grain size, composition, andtexture. Layering is on a centimetre to decimetre scale,and locally folded. White to light pink feldsparporphyroclasts, between 0.5 and 1 cm in diameter, arecommon; locally there are hornblende porphyroblasts(Figures 10 and 11). Inclusions are also relativelycommon and some have a foliation which is oblique tothe gneissosity (Figure 12), which led Ray (1980) topropose early deformation predating movement of theParker Lake Shear Zone. Lewry et al. (1980), however,were unable to find conclusive evidence for deformationpredating the shear zone, and interpreted the inclusionsas ‘tectonic fish’ that represent early stages ofprogressive strain rather than an earlier fabric.

Partly porphyroclastic granodiorite generally intrude thedioritic to quartz dioritic phases within this orthogneissbelt, but are also strongly foliated to mylonitic. Onesuch intrusion, the ‘Warner Creek’ granodiorite,exposed at kilometre 108 on Highway 905, yielded a U-Pb zircon age of 2566 ±8 Ma (Rayner et al., in review;Table 1).

Many outcrops in this belt also contain massive tomylonitic monzonitic to quartz-monzonitic rocks, whichare partly megacrystic (Figure 11). These rocks areprobably related to the 1.86 Ga Wathaman Batholith,but some of these megacrystic rocks could also beArchean.

Monzonitic Intrusive Suite

A suite of monzonite, quartz monzonite, andmonzodiorite intrudes the Warner Lake gabbroic suiteand the gneissic quartz diorite to granodiorite suite. Oneof the main intrusions is on the eastern shore of WarnerLake.

The suite is dominated by monzonitic rocks, but locallygrades into quartz-monzonite with up to 10% quartz.Gradation into more syenitic and monzodioritic varietiesis common. Generally the rocks are pink to grey,coarse-grained, massive to mylonitic, and commonlymegacrystic. The mafic mineral content varies between10 to 20%, and is dominated by biotite with minoramounts of epidote, hornblende, and titanite. Distinctunits of megacrystic quartz monzonite are generallycharacterized by 10 to 15% quartz. Pink K-feldsparmegacrysts up to 3 cm long compose up to 30% of therock and generally define a tectonic foliation (Figures13 and 14).

Most of the supracrustal remnants (see below) of thePeter Lake Domain are associated with and intruded bythis monzonitic suite. The suite is post-dated by pink tobrick-red granites (Figure 13), as well minor maficdykes.

Granitic Rocks

Leucogranitic and syenogranitic plutons, in partmegacrystic, underlie most of the area between Peter

Figure 10 - Feldspar porphyroclastic granodiorite gneissovergrown by hornblende blasts; UTM-E: 577566; UTM-N:6330978.

Figure 11 - A K-feldspar megacrystic quartz monzonite(related to Wathaman Batholith?) cutting a gabbro; UTM-E:576843; UTM-N: 6330120.

Figure 12 - Feldspar porphyroclastic quartz-diorite gneisswith a foliated xenolith; foliation in xenolith represents earlyfabric development during progressive strain (‘tectonicfish’), rather that a pre-existing fabric; UTM-E: 575791;UTM-N: 6328451.

Saskatchewan Geological Survey 11 Summary of Investigations 2002, Volume 2

Lake and Courtenay Lake, and also occur as lateintrusive sheets and dikes in the area between PeterLake and the Wathaman River (in part indicated bycross-hatching on the map in the accompanying mappackage).

Large plutons of coarse- to very coarse-grainedsyenogranite were delineated on northern Peter Lake,northern Combe Lake, northwestern Vollman Lake, andimmediately south of the Love Lake Leucogabbro. Mostof these bodies contain biotite and epidote, with onlyminor amounts of hornblende in a few outcrops. Sometextural variations exist.

The Vollman Lake syenogranite is coarse to very coarsegrained and locally megacrystic, with up to 2 cm longpink microcline crystals. It typically contains 25 to 30%coarse interstitial quartz, and up to 10% mafic mineralscomprising biotite, chlorite, and magnetite. One outcropcontains minor amounts of purple fluorite, largelylocated on late fractures. The granite is generally wellfoliated and because of its megacrystic nature has adistinct augen texture. It is intruded by mafic dykes, andby late granitic pegmatite sheets, which are in parttransposed and sheared. The western margin of thegranite is cut by northeast-trending shear zones, whichare likely related to the Needle Falls Shear Zone.

The coarse- to very coarse-grained syenograniteunderlying large parts of northern Combe Lake ischaracterized by 30 % quartz, and up to 15% maficminerals. In contrast to the Vollman Lake syenogranite,it contains hornblende as well as biotite, is generallyless deformed, and equigranular. Another distinctivefeature of this body, which was observed on manyoutcrops, is its seriate texture with gradational grain sizevariation from medium (1 to 2 mm) to very coarse (upto 2 cm). A geochronology sample of a fine-grainedfoliated gneiss from Combe Lake appears to have beencollected within the confines of this intrusion andyielded a U-Pb zircon age of 2580 Ma ±5 Ma (Rayneret al., in review; Table 1; Figure 4).

The syenogranite underlying most of Peter Lake is tentatively correlated with Ray’s (1980) ‘Robinson Lakemonzogranite’. It is pink to brick red, coarse grained, homogeneous, and massive to weakly foliated. It contains upto 10% biotite and minor amounts of magnetite. Local mylonite zones cause the development of an augen texture.

The granite immediately south of the Love Lake Leucogabbro was dated by Annesley et al. (1992) and yielded a U-Pb zircon age of 2566 Ma ±2 Ma and a titanite age of 2529 Ma ±4 Ma.

Emplacement of leucogranite was one of the last intrusive events. South of Warner Lake, a medium-grainedleucogranite cuts megacrystic quartz monzonite as well as monzodioritic to dioritic gneisses. On Combe Lake,several sheets of leucogranite cut the Combe Lake dioritic suite. The Love Lake Leucogabbro is also intruded byseveral leucogranite sheets, one of which is north trending and in part aplitic.

Leucocratic Fluorite-bearing Syenogranite

A leucocratic syenogranite, between Courtenay Lake and Vollman Lake at the northern end of the map area, islocally fluorite bearing and possibly of a peculiar age. Its northwestern margin is highly strained and cut by anextension of the Needle Falls Shear Zone, which obscures the relationship between the Peter Lake and Wollastondomains. A foliated syenogranite collected within the confines of this unit (outcrop was not observed by the presentauthors) yielded a U-Pb zircon age of 2086 +52/-8 Ma and a titanite age of 1809 ±15 Ma (Annesley et al., 1992).Although the precision of the zircon age is poor, it is similar to two other ages, which were obtained only a fewkilometres to the north within the Wollaston Domain. Therefore, the age is considered broadly accurate and the

Figure 13 - Foliated megacrystic monzonite cut by brick-redgranite; UTM-E: 567806; UTM-N: 6335513.

Figure 14 - Close-up of typical non-megacrystic monzonite;UTM-E: 564757; UTM-N: 6334290.

Saskatchewan Geological Survey 12 Summary of Investigations 2002, Volume 2

pluton may represent the intrusive root to rift-related quartz-feldspar porphyries in the Courtenay Lake Formation ofthe Wollaston Domain (Delaney et al., 1997; Ansdell et al., 2000).

Campbell River Group

A 1.5 km long and 200 m thick north-dipping monoclinal sequence of quartzitic to argillaceous sedimentary rocks,which lies between quartz monzonite bodies of the Peter Lake Complex, is correlated with the Campbell RiverGroup. The unit is exposed at kilometre 111 on Highway 905, in a low-lying area between two muskegs. A series oflarge outcrops provides good exposures for several hundred metres to the west of the highway. Further west,outcrops are fewer, and generally bound to topographically higher areas, which are interspersed with numerousareas of felsenmeer and block fields in the low-lying regions. One hundred metres to the east of the highway, the

Campbell River Group is coveredby muskeg and glacial deposits.

As part of a B.Sc. investigationundertaken by Rebecca Hunter, a100 by 150 m large outcropalongside the highway waschosen for detailed mapping andseveral stratigraphic sectionswere completed. Two additionalsections were completed fromoutcrops approximately 1.0 and1.4 km west of the highway.Based on these sections and thedetailed map, four units weredefined (Figure 15). All unitsshow consistent stratigraphic topindicators to the north and anoverall fining-upward succession.

Unit 1 consists primarily of avery fine-grained, ripple-laminated feldspathic arenite,with minor cross-bedded lensesof coarse- to very coarse-grainedquartz arenite and alternating 1 to10 cm thick argillaceous beds.Blue quartz grains, up to 5 mm indiameter are common in thequartz arenite beds (Figure 16).Measurements from 20 rippledforesets (Figure 17) in Unit 1,

yielded a unimodal east-southeast-trending (Figure 18)paleocurrents direction.

Unit 2 consists of coarse- to very coarse-grained quartzarenite with a few wavy, irregular argillite beds,between 1 and 5 cm thick. Bedding within this unit isdisturbed due to soft sediment deformation between thequartz arenite and argillaceous layers.

Unit 3 is an argillite with distinct 3 to 25 cm thick cross-bedded quartz arenite lenses, displaying scoured bases.Also present are 1 to 3 mm, wavy laminated quartzarenite layers showing truncated surfaces, whichconfirm a way-up direction to the northwest. The unit isfurther characterized by soft-sediment deformation inthe form of load casts, and ball-and-pillow structures.

The top of the exposed succession (Unit 4) is mainly anargillaceous unit with minor coarse-grained quartzarenite beds ranging from 2 to 5 cm thick. Unit 4 lacks

Figure 15 - Schematic cross-section through the Campbell River Group nearHighway 905.

Figure 16 - Pebbly layer in quartz arenite of Unit 1 withbrown, grey, and blue quartz pebbles up to 5 mm indiameter; UTM-E: 568708; UTM-N: 6329913.

Saskatchewan Geological Survey 13 Summary of Investigations 2002, Volume 2

the cross-bedded and laminated quartz arenite beds thatare characteristic of Unit 3.

In felsenmeer southwest of the large highway outcrop,angular blocks (20 to 80 cm in diameter) of pebblyfeldspathic wacke with flattened pebbles of quartz andfeldspar (2 to 10 mm in diameter) were observed, alongwith coarse- to very coarse-grained feldspathic areniteto subarenite. The latter are similar to the sub-arenite ofUnit 1. The pebbly feldspathic wacke, though notobserved in outcrop, may represent a coarse basal unitstratigraphically underlying Unit 1.

The stratigraphic sections of the Campbell River Groupquartzite (Figure 15) reveal a fining upward sequencebeginning with a pebbly, possibly channeled base,overlain by rippled beds with east-southeast-directedpaleocurrents and ending with primarily argillaceousbeds exhibiting load casts and ball-and-pillowstructures. This depositional sequence may beconsistent with a prodeltaic depositional environment,an interpretation that is strengthened by recognizing

that, in the east, the group comprises a primarily fine-grained and euxinic sedimentary sequence, including argillite,pelite and sulphidic mudstone (MacDougall, 1987). This suggests lower sedimentation rates and anoxic, deep-waterconditions.

Contacts between the Campbell River Group and surrounding quartz monzonite bodies of the Peter Lake Complexare not exposed. Close inspection of the plutonic rocks provided no evidence of Campbell River Group xenoliths,although MacDougall (1987) and Lewry et al. (1980) speculate on the presence of such xenoliths. Also, no intrusiverocks were observed on any of the Campbell River Group outcrops; based on our observations an intrusiverelationship therefore seems unlikely. A faulted contact is suggested by high-strain gradients from massive to

mylonitic in the adjacent quartzmonzonite bodies. Although weprefer an allochthonous origin forthe Campbell River Group, othermodels may have to beentertained as moregeochronological data becomeavailable. Also, an assessment ofmetamorphic conditions withinthe group compared to those ofthe surrounding rocks is needed.

Other Supracrustal Rocks

Xenoliths of supracrustal rocksoccur in some of the intrusions,particularly the Love LakeLeucogabbro, and also as isolatedoutcrops and small dismemberedunits, particularly between LoveLake and Warner Lake. Incontrast to the Campbell RiverGroup, all have beenmetamorphosed at upperamphibolite facies conditions.They comprise, in order ofdecreasing abundance, migmatiticpelite to psammite, amphibolitederived from mafic volcanicrocks, felsic volcanic rocks,quartzite, iron formation, andpolymictic conglomerate.

Figure 17 - Rippled foresets in quartz arenite beds of Unit1; stratigraphic top towards top of photo; UTM-E: 569736;UTM-N: 6330219.

Figure 18 - Paleocurrent data for Unit 1 of the Campbell River Group.

Saskatchewan Geological Survey 14 Summary of Investigations 2002, Volume 2

One unit of psammopelitic to pelitic migmatite is about 200 m thick and extends for about 2 km along strike, and istransected by Highway 905 just north of kilometre 118. It is enclosed by dioritic to gabbroic rocks of the WarnerLake gabbroic suite. Up to 50% of the unit is composed of a tonalitic leucosome that locally has plagioclaseporphyroblasts. Layering, caused by the transposition of locally generated medium- to coarse-grained tonaliticleucosome, biotite-rich melanosome, and a fine- to medium-grained biotite-rich paleosome, is generally complexlyfolded and injected by younger leucosome (Figure 19). Minor garnet and/or cordierite is locally present. Quartzveining is prevalent on some of the outcrops, but certain quartz-rich layers may be sedimentary in origin.

Up to 20% of the unit is made up of fine-grained amphibolite. These are generally internally homogeneous, butdisplay agmatitic textures (Figure 20) due to injection by tonalitic leucosome generated in the neighbouring peliticmigmatite. The amphibolite derives either from intermediate to mafic volcanic rocks or from dykes, and predates themigmatization.

Along strike, this mixed unit of pelitic migmatite and amphibolite passes into leucotonalitic diatexite, which isgenerally white weathering, medium- to coarse-grained and composed of plagioclase, quartz, and biotite.

Migmatitic sedimentary rocks are also exposed approximately 6 km southeast of those previously described. One 20by 20 m heterogeneous outcrop comprises a complexly folded succession of fine-grained migmatitic psammite,calcic psammopelite, impure quartzite, intermediatevolcaniclastic rocks, and minor silicate-facies ironformation. Biotite, garnet, and hornblende are the mainaluminium silicate minerals. The silicate-facies ironformation is thinly laminated, with alternating layers of‘chert’, magnetite, and quartzofeldspathic rock, as wellas garnet-quartz pods up to 10 cm in diameter andcontaining up to 50% garnet. Partial melting hasproduced a hornblende-plagioclase-rich leucosome inthe intermediate rocks and a plagioclase-quartz-garnet-bearing leucosome in the psammitic to psammopeliticrocks. Subsequently, these were intruded by sheets anddykes of diorite and granodiorite.

One isolated outcrop of polymictic pebble conglomerateand psammite lies along strike with some of themigmatitic psammopelite units. It is locatedapproximately 2 km northeast of Highway 905 and isabout 10 by 2 m in maximum dimensions. Layering isparallel to the main foliation. At the structural base ofthe succession, a several metre thick layer of polymicticconglomerate is exposed. It is composed of generally 1to 2 cm long, highly flattened pebbles of light greyfelsic volcanic rocks, minor fine-grained black maficrocks, and pink feldspar, set in a fine-grained psammiticmatrix. Rarely, clasts reach 10 cm in length and one ofthese is internally folded. Structurally and possiblystratigraphically overlying the conglomerate are grey- tobuff-weathering, fine- to very fine-grained stronglyfoliated quartzofeldspathic rocks of possible psammiticderivation.

A fine-grained plagioclase-phyric mafic rock (Figure21) occurs immediately north of the Love LakeLeucogabbro, and is interpreted as volcanic in origin;xenoliths of this unit can also be seen within the LoveLake leucogabbro. Several other units of fine-grainedamphibolite occur throughout the area, but aretexturally nondescript. Some may derive fromintermediate to mafic volcanic rocks; others mayrepresent sheared equivalents of dykes or may havedioritic to gabbroic protoliths.

Two outcrops of fine-grained felsic rocks, interpreted asvolcanic in origin are exposed in the Peter Lake area;one in Delorme Bay, and the other between Peter Lake

Figure 19 - Migmatitic psammopelite and amphibolite; insitu melting, but also later injection of leucosome; UTM-E:567281; UTM-N: 6335550.

Figure 20 - In situ melting of pelite (below pencil) producesleucosome; derived melt leucosome gets injected intoamphibolite (above pencil), producing agmatitic texture;outcrop on Highway 905; UTM-E: 565295; UTM-N:6336245.

Saskatchewan Geological Survey 15 Summary of Investigations 2002, Volume 2

and the Wathaman River, roughly on strike with, and2 km to the northeast of, the Campbell River Groupoutcrops. The Delorme Bay lakeshore outcrop is about 8by 8 m in maximum dimensions and is characterized bya layered and foliated succession containing dacitic tuffbreccia, laminated volcaniclastic rock, feldspar-porphyritic dacite, and aphanitic rhyodacite. All arelight grey to beige weathering, and have a very fine-grained felsic matrix containing about 5% biotite, aswell as minor amounts of muscovite and epidote.Isolated zones on the outcrop contain up to 5% garnet,likely an affect of alteration. Layering is on a scale of50 cm and on a centimetre scale in the laminatedvolcaniclastic interval. One example of cross-bedding inthis interval suggests a reworked, rather than primary,volcanic origin. The tuff breccia may be of pyroclasticorigin and the feldspar-porphyritic component likely hasa subvolcanic precursor. The depositional environmentsuggested by this succession is shallow water, proximalto a felsic volcanic centre.

The second outcrop, about 20 by 20 m in diameter,comprises medium-grey to light pinkish grey, very fine-grained dacitic and rhyolitic rocks. These rocks contain 20to 30% quartz, up to 15% (dacite) to 40% (rhyolite) K-feldspar, plagioclase, and minor amounts of biotite,muscovite, and opaque minerals. No primary features are preserved.

Several isolated examples of fine-grained pink quartzofeldspathic gneisses predating emplacement of quartzmonzonitic and monzonitic intrusions are exposed between Warner Lake and the Wathaman River. These gneissesare of presumed supracrustal origin.

b) Wollaston Domain and Needle Falls Shear Zone

A small 1 km2 area of the Wollaston Domain east of Courtenay Lake was mapped to better understand the contactrelationship between the Wollaston and Peter Lake domains. This area was previously mapped by Scott (1970) at1:10 000, Coombe (1994), and more recently by Delaney et al. (1997), who produced a series of schematic cross-sections.

Our mapping identified the following components of the Courtenay Lake Formation (Scott, 1970; Delaney et al.,1997): cross-bedded feldspathic psammite, intraformational polymictic boulder conglomerate, fine-grainedgarnetiferous feldspar-porphyritic dacite, highly magnetic mixed amphibolite (in part amygdaloidal or pillowed, butlargely of ambiguous origin), and minor impure partly garnetiferous quartzite. Bedding dips and faces generally tothe northwest, but as the Peter Lake Domain is approached, folding results in east-dipping bedding planes.Schistosity defined by biotite and muscovite dips consistently to the east, irrespective of the fold limb and thereforemust post-date this folding event. The schistosity steepens to subvertical within mylonite zones as the Needle FallsShear Zone is approached.

The highly strained contact between the Wollaston and Peter Lake domains in the Courtenay Lake area likelyrepresents a northeastward continuation of the Needle Falls Shear Zone. The eastern extent of the WollastonDomain includes sheared varieties of feldspathic psammite (muscovite-biotite gneiss), impure quartzite, andmicrodiorite. The western extent of the Peter Lake Domain is marked by a pink, fine-grained, homogeneous,mylonitic leucogranite containing biotite and minor muscovite. It grades easterly into a relatively homogeneous,pink, medium-grained equigranular, leucocratic, biotite syenogranite.

Further northeast, in the Cook Lake area, MacNeil et al. (1997) recognized an unconformity between the CourtenayLake Formation and rocks of the Peter Lake Domain including leucogranite and “variably granitizedquartzofeldspathic paragneiss”.

c) Wathaman Batholith and Parker Lake Shear Zone

The Wathaman Batholith is on the southeast side of the Peter Lake Domain and is overprinted by the Parker LakeShear Zone. The batholith is here represented by protomylonitic to ultramylonitic megacrystic quartz monzonite.Tectonic layering is on a scale of 10 to 50 cm and is defined by the degree of megacryst preservation, withprotomylonitic layers containing more than 50% relict megacrysts and ultramylonitic layers containing less than10% megacrysts. There are both gradational with sharp contacts between layers. Some of the layers are fine-grained

Figure 21 - Plagioclase-phyric mafic rock of presumedvolcanic origin; outcrop along Highway 905; UTM-E:565295; UTM-N: 6336245.

Saskatchewan Geological Survey 16 Summary of Investigations 2002, Volume 2

quartz monzonite to leucogranite, without any apparent relict feldspar megacrysts, but with highly ribboned quartz.In such cases, the sharp contact with neighbouring megacrystic quartz monzonite cannot simply be explained byvariable strain, but rather has to reflect a primary compositional variation (e.g., transposed dykes).

A weak subhorizontal stretching lineation is seen on some of the outcrops. Extensional shear bands and wingedporphyroclasts indicate a dextral sense of shear, consistent with previous interpretations (Lafrance and Varga,1996).

Late brittle deformation has resulted in widespread cataclasis, which can be observed on many of the outcrops lyingin the Parker Lake Shear Zone.

4. Economic Geology and Geochemistry

Table 2 contains new whole-rock geochemical data. No interpretation is provided at this time. Tables 3 and 4 showanalyses of grab samples to test for the presence of gold, copper, and PGEs. One previously recognized coppershowing on Combe Lake (SMDI 545) was examined, and a new occurrence was discovered during the summer (seebelow). Slightly elevated PGE concentrations were encountered in several of the analyzed samples of mafic-ultramafic rocks (Table 4); interestingly, one (sample RM0201-036) is located along strike of the newly discoveredcopper occurrence.

A preliminary general assessment of the western portion of the Peter Lake Domain suggests a potential for copper-nickel and possibly PGE mineralization within the Warner Lake gabbroic suite. The Love Lake Leucogabbro liesalong strike and likely hosts the Cu-Ni-PGE showing discovered by SMDC in 1982 (SIR assessment file 64E05-0028), approximately 20 km east-northeast of Love Lake in the Korvin Lake area. A systematic geochemical surveyof this pluton may detect additional prospective areas. The presence of primary igneous layering within the pluton,albeit sporadic, is encouraging.

a) Disseminated Sulphide Occurrences

Several new sulphide occurrences were discovered. Occurrence #1 is located approximately 3 km northeast of theWarner Lake gravel pit (Figure 4) and approximately 100 m north and within sight of a small unnamed lake (UTM-E: 573040; UTM-N: 6332599; ±6 m). It is exposed in a small 1 m2 outcrop of gabbroic to pyroxenitic rocks at theside of a small ridge. The rock is fairly heterogeneous and completely amphibolitized, with strongly varying maficmineral content. Minor east-west-trending shear zones are present. Hand samples from this outcrop contain 5 to10% disseminated sulphides, comprising predominantly pyrrhotite (5%), with minor amounts of chalcopyrite (1%),pyrite (1%), and azurite (trace). The magnetic susceptibility is fairly low (i.e., an average of 0.5x10-3 SI). Ananalysis of a grab sample (RM0201-128) has slightly elevated concentrations of Au, Pt, Pd, Cu, and Ni (Tables 3and 4).

Nearby outcrops of gabbroic to pyroxenitic rocks only contain trace amounts of sulphides. Along the lakeshore,south and structurally below the gabbro, are felsic mylonites. These are likely related to a belt of granitic togranodioritic rocks, which post-date the gabbro and were later mylonitized.

Two kilometres west of this occurrence, within the same belt of dioritic to gabbroic rocks, is a weakly mineralizedgabbroic to ultramafic rock with up to 2% disseminated pyrite, pyrrhotite, and chalcopyrite. An analysis of a grabsample of gabbro has no enrichment of PGEs (Table 4).

A clinopyroxenite (occurrence #2; Figure 4), which also forms part of the Warner Lake gabbroic suite, containingminor amounts of disseminated pyrite, magnetite and chalcopyrite was sampled on north Warner Lake (RM0201-036) and gave slightly elevated PGE concentrations (Table 4) and strongly enriched Cr concentration (Table 2).

Still in the same belt, quartz dioritic to gabbroic rocks on the western shore of Warner Lake, contain minor amountsof disseminated pyrite and chalcopyrite. These rocks have also been affected by shearing and silicification in theform of minor quartz veins. Millimetre-sized pyrite cubes are associated with these quartz veins and withinmylonitic section. Two grab samples of these sheared rocks were analyzed (sample RM0201-027) and revealed nosignificant concentrations of gold or copper (Table 3).

A small outcrop of ultramafic actinolite schist (occurrence #3; Figure 4) forms part of a larger unit of ultramaficrocks in the hanging wall of the Campbell River Group. The ultramafic rocks are interpreted to be of intrusiveorigin. A sample of the actinolite schist (RH0201-600) was analyzed and had elevated concentration of Au, Ag, andCu (Tables 3 and 4).

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178

Cs

3.7

1.3

5.5

3.6

0.9

0.1

2.6

0.6

1.6

1.2

1.1

Ba

1,1

50

505

1,0

20

1,4

20

450

148

269

256

125

1,8

10

894

Sr

697

927

505

413

943

79

251

145

42

462

176

Tl

0.9

60.1

80.7

90.9

50.0

90.1

20.6

60.2

91.9

20.8

30.9

0G

a25

24

19

20

23

813

12

19

23

17

Ge

1.5

1.7

1.5

0.9

1.3

1.6

1.2

0.9

1.1

1.2

1.3

Ta

0.8

30.3

80.4

30.5

10.0

90.0

70.1

00.0

80.4

40.3

61.5

3N

b13.5

6.7

4.1

7.8

2.0

1.2

1.2

1.2

7.0

10.3

14.9

Hf

4.2

3.0

1.3

2.8

0.7

0.6

0.7

0.6

2.8

11.4

4.1

Zr

187

122

42

104

23

20

22

22

74

529

143

Y22.0

19.5

16.2

20.2

13.5

9.2

6.4

3.7

6.4

23.4

24.1

Th

8.3

71.2

53.1

16.0

20.9

70.6

00.7

80.6

830.6

22.7

27.2

U1.7

70.4

01.8

81.1

40.2

80.2

50.3

00.1

311.3

1.3

34.2

3La

60.8

31.6

19.3

30.7

16.3

6.7

25.3

95.6

19.5

0181

44.9

Ce

122

68.2

41.3

63.2

35.5

14.5

11.8

11.6

22.8

320

89.6

Pr

13.7

8.5

65.1

07.3

84.6

21.8

71.5

31.3

82.5

131.8

9.5

4N

d53.8

37.0

22.1

29.8

20.6

8.7

76.9

05.7

79.5

8108

33.8

Sm

8.9

06.7

44.3

65.4

33.9

51.9

61.4

81.0

62.0

112.5

5.4

1E

u2.7

82.5

61.6

41.4

81.7

40.7

06

0.5

95

0.4

84

0.3

36

2.0

30.6

55

Gd

6.7

55.8

13.8

24.4

83.5

51.9

11.3

60.8

31.3

86.1

63.6

0T

b0.7

90.7

10.5

30.6

40.4

50.3

00.2

10.1

20.1

90.7

40.5

7D

y4.1

73.7

92.9

63.6

12.5

51.7

11.2

40.6

91.0

14.3

33.6

5H

o0.7

40.6

90.5

80.6

90.4

70.3

40.2

40.1

30.2

10.7

80.7

4E

r1.9

91.8

71.6

31.9

21.2

90.9

30.6

30.3

50.6

32.3

52.2

4T

m0.2

54

0.2

47

0.2

36

0.2

89

0.1

65

0.1

23

0.0

86

0.0

51

0.1

21

0.3

38

0.4

04

Yb

1.6

01.6

91.5

21.9

61.1

00.8

20.5

70.3

30.8

92.1

92.6

9Lu

0.2

09

0.2

43

0.2

24

0.2

97

0.1

57

0.1

21

0.0

82

0.0

56

0.1

81

0.3

26

0.4

07

Tab

le 2

(co

nti

nu

ed)

- W

hol

e-ro

ck m

ajor

an

d tr

ace

elem

ents

geo

chem

ical

dat

a fo

r se

lect

ed g

rab

sam

ples

; an

alys

es o

btai

ned

fro

m A

ctiv

atio

n L

abor

ator

ies

Ltd

.; n

egat

ive

valu

eseq

ual

‘n

ot d

etec

ted’

at t

hat

low

er li

mit

; ab

brev

iati

ons:

su

l, su

lph

ide;

py,

pyr

ite;

cpy

, ch

alco

pyri

te;

mt,

mag

net

ite;

an

d h

t, he

mat

ite;

per

cen

tage

giv

en r

efle

cts

tota

l opa

que

min

eral

con

ten

t.

Saskatchewan Geological Survey 17 Summary of Investigations 2002, Volume 2

Sa

mp

le I

DR

M0

20

1-0

95

R

M0

20

1-1

01

RM

02

01

-11

5R

M0

20

1-1

27

RM

02

01

-13

8R

M0

20

1-1

42

RM

02

01

-16

4R

M0

20

1-1

71

RM

02

01

-17

7R

M0

20

1-1

78

RM

02

01

-18

2

Fie

ld d

esc

rip

tion

Gn

t-b

ea

rin

g

feld

spa

thic

ps

amm

ite

Str

on

gly

fo

l. le

uco

gra

nite

w

dis

s. p

yrite

Le

uco

ga

bb

ro w

d

iss.

pyr

ite p

lus

magne

tite

Le

uco

ga

bb

ro w

d

iss.

su

lph

ide

s a

nd

ma

gn

etit

e

Dio

rite

Fin

e-g

rain

ed

a

mp

hib

olit

eG

abbro

w 2

%

dis

s. p

y, p

o,

cpy

(SM

DI 545)

Gra

no

dio

rite

Qu

art

z-m

on

zon

iteG

ran

iteM

eg

acr

ystic

m

onzo

nite

Ge

ne

ral a

rea

Ea

st C

ou

rte

na

y Lake

Ea

st C

ou

rte

na

y Lake

Lo

ve L

ake

are

aS

ou

th o

f 'Z

igg

y L

ake

'L

ove

La

ke a

rea

Ea

st o

f L

ove

La

ke C

om

be

La

keH

igh

wa

y 9

05

~

kilo

me

tre

11

7H

ighw

ay

905

~ k

ilom

etr

e 1

14

Hig

hw

ay

905

~ k

ilom

etr

e 1

21

Hig

hw

ay

905

~ k

ilom

etr

e 1

13

UT

M-E

(N

AD

83

)5

64

42

15

64

85

65

63

44

25

61

39

95

67

77

45

70

82

75

72

50

75

66

14

75

67

63

35

63

81

25

68

23

3U

TM

-N (

NA

D 8

3)

63

63

16

46

36

25

56

63

39

65

36

33

99

55

63

37

15

36

33

62

38

63

55

01

46

33

48

80

63

32

51

76

33

82

73

63

31

84

2(in w

t %

)S

iO2

57.1

573.1

048.8

745.5

148.0

450.3

148.8

369.5

772.9

875.9

658.0

1T

iO2

1.4

06

0.5

31

1.0

98

1.0

05

1.2

15

2.1

01

0.3

97

0.3

64

0.2

59

0.1

41

0.7

39

Al2

O3

16

.21

12

.86

18

.08

18

.39

18

.22

14

.77

14

.71

14

.46

13

.96

12

.73

19

.09

Fe

2O

31

1.0

12

.49

12

.71

11

.64

13

.59

10.6

610.2

32.6

82.2

31.7

35.6

6M

nO

0.3

54

0.0

66

0.1

78

0.1

46

0.1

51

0.1

81

0.1

63

0.0

35

0.0

39

0.0

17

0.1

18

MgO

1.2

40.4

34.7

25.6

34.6

64.8

810.0

91.1

10.3

40.2

61.5

2C

aO

5.6

60.7

99.3

614.4

24.9

511.7

512.8

02.1

11.2

20.7

03.6

3N

a2O

1.5

42.5

93.0

41.5

14.2

33.3

41.4

03.7

93.8

43.6

74.1

8K

2O

4.5

06.1

90.8

30.4

13.0

40.3

00.1

64.6

64.8

94.7

15.2

5P

2O

50.5

90.1

40.4

60.1

10.3

01.2

70.0

50.1

50.0

70.0

40.2

4L.O

.I.

0.6

01.0

60.7

31.4

41.8

30.6

71.1

31.0

90.3

70.5

41.1

3T

ota

l1

00

.25

10

0.2

31

00

.07

10

0.2

11

00

.21

10

0.2

19

9.9

61

00

.02

10

0.2

01

00

.48

99

.56

(in p

pm

)C

r177

-20

-20

-20

34

132

38

26

-20

-20

-20

Co

29

130

36

32

12

65

51

27

Sc

32

725

47

36

21

42

56

316

V183

14

266

351

235

237

149

31

7-5

45

Bi

1.0

-0.1

-0.1

0.1

0.1

0.2

0.3

0.4

-0.1

-0.1

-0.1

Sn

12

-1-1

32

-15

1-1

-1R

b254

255

24

19

116

53

145

106

105

114

Cs

23.6

3.3

1.5

0.9

2.2

-0.1

1.1

2.1

0.5

0.5

1.3

Ba

1537

1618

546

148

1387

114

56

1438

1344

304

3950

Sr

247

180

1,0

00

735

403

2,2

70

454

632

253

58

819

Tl

1.4

81

.88

0.1

50

.14

0.6

9-0

.05

-0.0

51

.21

0.5

20

.56

0.7

1G

a28

17

21

17

25

24

13

20

17

16

23

Ge

2.0

0.9

1.1

1.3

1.2

2.2

1.3

1.1

0.8

1.1

1.1

Ta

0.6

62.1

60.1

30.0

70.8

30.7

10.0

61.1

10.7

50.2

80.4

2N

b11.6

31.3

4.3

2.1

15.8

12.5

2.5

12.2

10.5

6.8

10.1

Hf

6.2

11.9

1.6

0.8

6.8

4.0

1.0

5.2

3.7

4.8

12.8

Zr

234

435

60

22

231

139

28

163

123

154

587

Y36.3

40.5

14.4

9.7

48.0

14.0

11.9

10.2

22.2

14.9

16.5

Th

6.1

133.7

1.0

80.4

34.7

03.9

40.5

426.7

11.5

8.2

015.7

U2.8

06.2

10.2

90.1

31.1

51.3

00.1

34.5

80.7

41.0

81.2

7La

74.4

158

17.9

7.0

550.2

61.8

5.9

160.3

45.1

53.2

146

Ce

146

321

38.6

15.6

107

130

13.7

107

86.7

102

260

Pr

17.7

33.6

5.2

82.2

213.4

16.4

2.0

011.6

9.9

511.3

25.7

Nd

68.4

113

23.0

10.4

53.7

66.1

9.5

039.7

36.0

38.3

86.1

Sm

10.6

14.3

4.4

42.3

910.6

9.7

62.2

35.4

86.3

95.5

49.9

7E

u2.7

32.2

91.8

51.0

02.4

03.4

70.7

97

1.2

41.1

90.4

34

3.4

8G

d8.0

79.4

13.7

92.1

09.0

16.3

52.2

13.3

44.9

23.9

26.2

2T

b1.2

41.3

90.5

60.3

61.6

30.7

40.4

10.4

00.8

40.5

60.7

2D

y6.7

47.5

42.8

41.9

39.0

63.1

72.3

31.9

04.4

52.8

13.3

6H

o1.3

01.4

80.5

30.3

71.7

50.5

00.4

60.3

30.8

00.5

30.5

9E

r3.9

44.7

51.4

61.0

35.1

51.3

91.2

91.0

02.2

41.5

41.8

7T

m0.5

61

0.7

45

0.2

13

0.1

38

0.8

14

0.1

66

0.1

91

0.1

52

0.3

13

0.2

39

0.2

62

Yb

3.8

04.9

61.3

20.9

45.1

91.0

21.2

11.0

21.9

01.4

91.6

5Lu

0.5

60

0.7

29

0.1

88

0.1

36

0.7

31

0.1

28

0.1

78

0.1

48

0.2

47

0.2

21

0.2

48

Saskatchewan Geological Survey 18 Summary of Investigations 2002, Volume 2

Tab

le 2

(co

nti

nu

ed)

- W

hol

e-ro

ck m

ajor

an

d tr

ace

elem

ents

geo

chem

ical

dat

a fo

r se

lect

ed g

rab

sam

ples

; an

alys

es o

btai

ned

fro

m A

ctiv

atio

n L

abor

ator

ies

Ltd

.; n

egat

ive

valu

eseq

ual

‘n

ot d

etec

ted’

at t

hat

low

er li

mit

; ab

brev

iati

ons:

su

l, su

lph

ide;

py,

pyr

ite;

cpy

, ch

alco

pyri

te;

mt,

mag

net

ite;

an

d h

t, he

mat

ite;

per

cen

tage

giv

en r

efle

cts

tota

l opa

que

min

eral

con

ten

t.

Saskatchewan Geological Survey 19 Summary of Investigations 2002, Volume 2

Tab

le 3

- A

nal

yses

of

gold

an

d ot

her

ele

men

ts f

or s

elec

ted

grab

sam

ples

; an

alys

es o

btai

ned

fro

m A

ctiv

atio

n L

abor

ator

ies

Ltd

.; n

egat

ive

valu

es e

qual

‘n

ot d

etec

ted’

at t

hat

low

er li

mit

; ab

brev

iati

ons:

na,

not

an

alyz

ed;

oth

er a

bbre

viat

ion

s as

in T

able

2.

Sam

ple

ID

RM

0201-

502

RH

0201-

540

RH

0201-

600

RH

0201-

601

RM

0201-

027

RM

0201-

095

RM

0201-

101

RM

0201-

113

RM

0201-

125

RM

0201-

128

RM

0201-

12

9

RM

0201-

147

RM

0201-

149

Fie

ld

de

scri

ptio

nQ

ua

rtz

vein

w

ith p

yrite

in

she

are

d

ga

bb

ro

Le

uco

ga

bb

ro

with

su

lph

ide

sA

ctin

olit

e

sch

ist

(#3

in

F

igu

re 4

)

Defo

rmed

qu

art

z m

onzo

nite

w

ith 3

%

sulp

hid

es

Qu

art

z ve

in

with

pyr

ite in

sh

ea

red

le

uco

dio

rite

Ga

rne

tife

rou

s fe

ldsp

ath

ic

psam

mite

Str

on

gly

fo

l. le

uco

gra

nite

w

ith

dis

sem

ina

ted

p

yrite

Me

ga

crys

tic q

tz

monzo

nite

with

d

iss

py,

po

, cp

y,

mt

Le

uco

ga

bb

ro

with

dis

s. p

yrite

a

nd

ma

gn

etit

e

Ga

bb

ro w

ith

dis

sem

ina

ted

su

lph

ide

s (#

1 in

F

igu

re 4

)

Fo

liate

d

monzo

nite

with

d

isse

min

ate

d

pyr

ite

Am

ph

ibo

lite

with

d

isse

min

ate

d

sulp

hid

es

an

d

magnetit

e

Sili

cifie

d g

ab

bro

w

ith d

iss.

pyr

ite

(#4

in F

igu

re 4

)

UT

M-E

(N

AD

83

)5

65

46

95

63

79

75

69

65

85

69

56

75

63

83

45

64

42

15

64

85

65

74

28

75

62

49

25

73

04

05

73

12

75

69

08

95

70

02

2

UT

M-N

(N

AD

83

)6

33

85

55

63

38

94

06

33

03

25

63

30

31

06

33

45

68

63

63

16

46

36

25

56

63

30

47

76

33

90

42

63

32

59

96

33

39

40

63

40

63

26

34

08

43

Mass

g

26.7

331.8

32.0

832.6

831.7

830.5

427.8

629.8

832.4

628.0

126.7

535.7

131.2

2

Au

ppb

-2-2

135

6-2

-2-2

-2-2

35

-2-2

156

Ag

ppm

na

-0.3

1.5

0.8

na

0.4

-0.3

0.8

-0.3

-0.3

-0.3

-0.3

3.3

As

ppm

12.1

1.3

11.5

-0.5

-0.5

1-0

.5-0

.51.4

-0.5

1.9

Co

ppm

641

97

24

45

33

-15

50

99

13

28

18

Cr

ppm

11

18

21

3112

13

129

7-5

32

387

12

-513

Cu

ppm

10

59

117

740

25

44

4104

90

514

27

32

1849

Mn

ppm

556

1582

262

11526

77

2814

487

259

1476

1372

1181

2060

542

Mo

ppm

23

32

13

76

12

4-1

2

Ni

ppm

12

418

038

13

55

-1-1

11

500

2-1

7

Pb

ppm

9-3

536

24

17

77

614

-3-3

14

4-3

Sm

ppm

0.3

3.7

2.1

3.8

0.3

10.4

15.6

8.7

2.3

2.4

6.6

9.8

1.1

Sr

ppm

50

824

10

9402

6207

141

114

784

334

508

957

189

Vpp

m38

314

24

775

5200

15

18

445

173

81

271

110

Ypp

m4

10

11

30

125

31

75

10

15

25

5

Zn

ppm

33

139

18

4159

18

153

99

889

209

155

146

255

114

Rb

ppm

na

54

69

168

na

207

241

103

-15

-15

95

-15

-15

Ba

ppm

na

400

800

2000

na

1600

1600

2400

240

280

1700

420

80

Sb

ppm

na

0.3

0.2

0.3

na

0.5

-0.1

-0.1

-0.1

-0.1

-0.1

-0.1

-0.1

Ta

ppm

na

-0.5

-0.5

1.3

na

-0.5

3.8

-0.5

0.9

-0.5

-0.5

-0.5

-0.5

Th

ppm

na

0.9

1.9

2.1

na

5.4

31.8

18.2

0.6

1.2

4.9

1.1

-0.2

U

ppm

na

0.9

-0.5

-0.5

na

3.3

7.9

-0.5

-0.5

-0.5

1.3

1.6

-0.5

La

ppm

0.9

15.7

11.2

20.6

1.1

75.9

178

96.5

8.2

8.2

36.5

32.1

3.5

Ce

ppm

na

38

22

39

na

160

356

188

20

19

79

76

9

Nd

ppm

na

16

14

12

na

54

110

59

-5-5

32

45

-5

Eu

ppm

na

1.6

0.9

1.3

na

2.5

2.3

1.9

10.8

23.5

0.6

Tb

ppm

na

-0.5

-0.5

-0.5

na

0.7

1.3

-0.5

0.5

-0.5

-0.5

0.9

-0.5

Lu

ppm

na

0.1

80.1

90.3

na

0.5

50.7

50.1

70

.13

0.1

30.3

40.2

80.0

9

Sc

ppm

4.1

24.8

20.3

21.7

0.5

30.2

6.3

8.1

30

26.2

17.9

34.6

10.2

Yb

ppm

na

1.2

1.2

2na

3.7

4.9

10.8

0.8

2.1

1.9

0.6

Fe

%

1.6

59.3

310

.94.1

51.7

17.7

71.8

93.6

911.2

9.1

5.7

10.7

3.8

1

Na

%

0.1

62.4

40.8

2.0

20.0

31.1

21.9

73.4

11.6

61.1

33.7

42.3

70.7

5

Al

%0.9

86.0

35.1

715.7

50.1

55.6

83.5

14.0

54

.70

5.7

56.6

95.3

52.0

1

Ca

%2.4

06.6

26.6

05.6

30.1

53.9

90.4

10.7

87.1

65.8

22.6

87.1

12.4

1

K%

0.2

40.7

91.5

93.2

70.0

83.4

44.7

25.4

80

.26

0.8

12.2

00.1

90.1

3

Mg

%0.7

53.1

26.7

84.3

30.0

40.6

90.2

50.3

83

.53

8.4

61.2

73.0

81.1

9

P%

0.0

12

0.1

25

0.0

23

0.0

18

0.0

02

0.1

83

0.0

43

0.0

33

0.0

23

0.0

22

0.0

98

0.4

03

0.0

13

S%

0.0

14

0.1

33

0.4

59

0.0

72

1.4

83

0.2

72

0.4

37

1.8

73

0.2

16

0.4

15

0.0

36

0.2

44

0.3

61

Ti

%0

.07

0.6

30

.40

0.1

4-0

.01

0.8

30

.25

0.3

70

.80

0.3

40

.47

0.8

80

.09

Saskatchewan Geological Survey 20 Summary of Investigations 2002, Volume 2

Table 4 - Au, PGE, and Cu-Ni-Zn analyses for selected intermediate to ultramafic rocks from the Peter Lake area; analysesobtained from Activation Laboratories Ltd.; negative values equal ‘not detected’ at that lower limit; abbreviations as in Table2.

The best geochemical results this year were obtained from a sample of silicified, chloritized, and sheared gabbro ofthe Love Lake Leucogabbro (occurrence #4; Figure 4). A 40 by 40 m large outcrop of medium-grained, black andwhite-weathering, equigranular, homogeneous, massive to weakly foliated gabbro is cut by minor shear zones. Theshear zones are characterized by chloritization, silicification, and up to 2% disseminated pyrite, magnetite andchalcopyrite. A grab sample of this sheared gabbro (RM0201-149) returned 3.3 ppm Ag, over 100 ppb Au, and1849 ppm Cu, but no elevated concentrations of PGEs (Tables 3 and 4).

A copper occurrence (SMDI 545) in gabbroic rocks of the Combe Lake dioritic suite is exposed in a bay along theeastern shore of Combe Lake (Scott, 1970; Figure 4). It comprises disseminated chalcopyrite, pyrite, pyrrhotite, andmalachite totalling about 2% sulphides. The sulphides are in part remobilized on late fractures. A grab sample(RM0201-164) was analyzed and gave slightly elevated concentration of Cu and Ni (Table 4).

5. Thermotectonic History

Only limited data are currently available to unravel the complex structural history of the area. As it is apredominantly plutonic domain, the rocks are generally not layered and therefore rarely folded at outcrop scale.Second-generation foliations are also scarce. Similarly, assessing the metamorphic grade was difficult, because ofthe preponderance of plutonic rocks. In addition, little geochronological data are available to provide an absoluteframework for the different thermotectonic phases.

Nevertheless, a preliminary general framework is presented in Figure 22. Early D1 deformation was likelyNeoarchean in age based on a number of observations: 1) the Love Lake Leucogabbro, which is assumed to becontemporaneous with the 2.65 Ga Swan River Gabbro (Corrigan et al., 2001), contains deformed xenoliths ofmafic volcanic rocks (Figure 6); 2) one clast in the lone outcrop of polymictic conglomerate observed to date, isinternally folded; and 3) the monzonitic intrusion east of Warner Lake contains a small unit of isoclinally foldedmigmatitic psammopelite; the monzonite possibly post-dates migmatization and isoclinal folding of the psammite.Not all of these signs of early deformation are necessarily related to the same thermotectonic event.

The main regional foliation, which affects the majority of units in the Peter Lake Domain, was formed during asecond (D2) deformational event and resulted in the development of gneissic fabrics and alignment of planarmineral.

A third regional deformational event (D3) is manifested in east-northeast-trending, upright, outcrop- to map-scaleclose to tight folds. F3 fold axes were rarely measured, but are likely subhorizontal based on an equal areaprojection of all measured S2 foliations (not shown). One such map-scale fold is preserved on north Warner Lake.The orientation of a third-generation schistosity (S3) relative to the S2 gneissic fabric, which is here exhibited bypartly sheared granodioritic to dioritic rocks, suggests the presence of a map-scale antiform paralleling a bay on

Sample ID Field description General area Location (NAD 83) Au Pt Pd Cu Ni Zn

UTM-E UTM-N ppb ppb ppb ppm ppm ppm

RM0201-600 Actinolite schist Highway 905, kilometre 111.5 (#3 in Figure 4) 569658 6330325 116 -5 4 na na na

RM0201-013 Gabbro Wathaman River 571800 6332570 -2 -5 -4 na na na

RM0201-021 Amphibolite (py: 1%) Highway 905, kilometre 115 566699 6333492 -2 -5 -4 na na na

RM0201-024 Sheared gabbro (py>cpy: 1%) Warner Lake 564307 6334570 -2 -5 -4 na na na

RM0201-026 Quartzdiorite (py: 1%) Warner Lake 563834 6334568 2 -5 -4 na na na

RM0201-029 Leucogabbro (mt>ht: 5%) Love Lake 562952 6340090 -2 -5 -4 na na na

RM0201-032 Gabbro (po, py, cpy: 2%) North of Gravel Pit 571075 6332222 -2 -5 -4 na na na

RM0201-036 Clinopyroxenite (py>mt>cpy: 2%) Warner Lake (#2 in Figure 4) 564215 6335237 12 66 46 na na na

RM0201-041 Melagabbro Love Lake 566916 6337492 4 -5 -4 na na na

RM0201-046 Actinolite schist (1% sul) Wathaman River 576340 6329378 -2 -5 -4 na na na

RM0201-049 Pyroxenite (py: 2%) Warner Lake 562629 6329633 -2 -5 -4 na na na

RM0201-083 Gabbro (py: 1%) Warner Lake 561190 6335820 -2 -5 -4 na na na

RM0201-089 Diorite (py: 1%) Warner Lake 564452 6336602 -2 -5 -4 na na na

RM0201-115 Leucogabbro (mt>py: 5%) South Peter Lake 563442 6339653 12 -5 -4 48 4 105

RM0201-125 Leucogabbro (mt>py: 5%) South of Ziggy Lake 562492 6339042 3 -5 -4 na na na

RM0201-127 Leucogabbro (py + po: 2%) South of Ziggy Lake 561399 6339955 4 -5 4 113 10 72

RM0201-128 Gabbro (po>py>cpy: 5%) Northeast of gravel pit (#1 in Figure 4) 573040 6332599 33 37 27 na na na

RM0201-138 Diorite (py: 1%) Love Lake 567774 6337153 3 -5 -4 76 4 124

RM0201-147 Amphibolite (py>po: 3%) North of Love Lake 569089 6340632 3 -5 -4 na na na

RM0201-149 Silicified gabbro (py 1%) North of Love Lake (#4 in Figure 4) 570022 6340843 111 -5 -4 na na na

RM0201-164 Gabbro (po, py, cpy: 2%) Combe Lake (SMDI 545) 572507 6355014 7 19 31 746 186 68

Saskatchewan Geological Survey 21 Summary of Investigations 2002, Volume 2

northwestern Warner Lake. The southern shore of thebay parallels the south-dipping s-limb, and the northshore parallels the north-dipping z-limb of a tight map-scale, slightly east-plunging F3-fold. Figure 23 showsan outcrop-scale third generation S-fold, related to thismajor structure. The fold deforms earlier F2 isoclinalfolds and has an axial planar schistosity defined bybiotite. Outcrops within the gneissic granodiorite toquartz diorite suite just north of the Parker Lake ShearZone, also commonly display tight F3 folds and S3schistosity oblique to the S2 gneissic fabric.

At least one upper amphibolite facies metamorphicevent, likely coinciding with D2, has affected largeparts of the Peter Lake Domain, as well as sedimentaryrocks along the northwestern margin of the Peter LakeDomain (MacNeil et al.,1997). The Love LakeLeucogabbro, Warner Lake gabbroic suite, and themigmatitic supracrustal rocks between Peter Lake and

Figure 22 - Preliminary schematic illustration of the thermotectonic history of the western Peter Lake Domain.

Figure 23 - F3 fold with axial planar biotite refolding earlierisoclinal fold; northwestern bay of Warner Lake; UTM-E:561532; UTM-N: 6335918.

Saskatchewan Geological Survey 22 Summary of Investigations 2002, Volume 2

Warner Lake were all affected by this high-grade event. It is unclear whether the monzonitic to granitic rocks of thesouthern Peter Lake Domain were also affected by the high-grade event.

However, it is clear that the Campbell River Group has not been exposed to this upper amphibolite faciesmetamorphic event. It is a lower amphibolite facies, north-dipping and north-facing monoclinal sequence, wedgedbetween sheared monzonitic rocks and exhibits no evidence of any major folding or overturned sections. Theorientation of andalusite porphyroblasts overgrowing bedding in one locality is the same as the axial plane of ametre-scale, north-dipping and east-plunging z-fold measured at another location (Figure 23). This suggests that thesequence is on the z-limb of a major slightly east-plunging F3 fold. However, an earlier fracture cleavage andmuscovite schistosity preserved in argillaceous beds near the base of the group, is consistent with formation on thes-limb of an earlier, recumbent? F2? fold suggesting that the Campbell River Group has been doubly folded on amap scale. Based on the low metamorphic grade of the succession and the high-strain gradient in surrounding quartzmonzonite, it seems likely that the group is allochthonous; alternatively, it may post-date the high-grademetamorphic event. Lower amphibolite facies metamorphism coincided with development of the F3 folds.Emplacement of the group into its present allochthonous position may have coincided with thrusting parallel to theF2 axial planes.

The schistosity in 2.076 Ga feldspathic psammite and 2.086 Ga leucogranite (Table 1) in the Courtenay Lake area atthe northern boundary of the Peter Lake Domain is moderately to steeply southeast dipping and defined by thealignment of muscovite and biotite, which grew during low-grade metamorphic conditions. This fabric is possiblyrelated to, and of the same age as, the D3 Needle Falls Shear Zone, i.e., younger than 1.86 Ga (Stauffer and Lewry,1993).

A dyke in the megacrystic syenogranite intrusion northwest of Vollman Lake exhibits two fabrics. The dyke dips tothe southeast and has a strong schistosity defined by biotite and epidote trending parallel to the direction of thedyke. A second foliation is defined by hornblende and dips more southerly. The enclosing syenogranite exhibitsonly the second foliation, which is defined by biotite. This second foliation is likely related to the regional D3 event.The earlier foliation in the mafic dyke might be related to dyke emplacement.

Gentle map-scale open warping of units and decimetre- to metre-scale open folding are related to northeast-trendinglate open folds (F4). Late brittle subvertical faulting is generally northerly trending and likely related to the F4folding.

6. Acknowledgments

Shawna Leatherdale, Jason Craven, and Vance Hachkewich provided excellent and cheerful field assistance duringthe entire summer. Field visits by Survey colleagues Janet Campbell, Colin Card, Gary Delaney, Mike Gunning, andGary Yeo were very helpful in improving the map and report. Jean Graham of Johnson River Camp providedlogistical and moral support, particularly on the several occasions when the food order had been delayed or mixedup down south. Revisions by Ken Ashton and Gary Delaney improved the manuscript.

7. References

Annesley, I.R., Madore, C., and Krogh, T.E. (1992): U-Pb geochronology of some granitoids from the Peter LakeDomain: A summary; in Summary of Investigations 1992, Saskatchewan Geological Survey, Sask. EnergyMines, Misc. Rep. 92-4, p168-171.

Ansdell, K.M., MacNeil, A., Delaney, G.D., and Hamilton, M.A. (2000): Rifting and development of the Hearnecraton passive margin: Age constraints from the Cook Lake area, Wollaston Domain, Trans-Hudson Orogen,Saskatchewan (extended abstract); GeoCanada 2000, Calgary, May 2000, Conference CD, ext. abstr. #777.

Bickford, M.E., Van Schmus, W.R., Macdonald, R., Lewry, J.F., and Pearson, J.G. (1986): U-Pb zircongeochronology project for the Trans-Hudson: Current sampling and recent results; in Summary ofInvestigations 1986, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 86-4, p101-107.

Bickford, M.E., Van Schmus, W.R., Collerson, K.D., and Macdonald, R. (1987): U-Pb zircon geochronologyproject: New results and interpretation; in Summary of Investigations, Saskatchewan Geological Survey, Sask.Energy Mines, Misc. Rep. 87-4, p76-79.

Bickford, M.E., Rayner, N.M., and Stern, R.A. (2002): The exotic origin of the Sask craton, Trans-Hudson Orogenrevealed by new SHRIMP zircon U-Pb ages; Geol. Assoc. Can./Miner. Assoc. Can., Jt. Annu. Meet.,Saskatoon, Abstr. Vol. 27, p10.

Saskatchewan Geological Survey 23 Summary of Investigations 2002, Volume 2

Coombe, W. (1994): Sediment-hosted Base Metal Deposits of the Wollaston Domain, Northern Saskatchewan;Saskatchewan Geological Survey, Sask. Energy Mines, Rep. 213, 108p.

Corrigan, D. (2001): Geology, northern Reindeer Lake, Saskatchewan; Geol. Surv. Can., Open File 1394, 1:100 000scale map.

Corrigan, D., MacHattie, D.G., and Chakungal, J. (2000): The nature of the Wathaman Batholith and its relationshipto the Archean Peter Lake Domain along the Reindeer Lake Transect, Saskatchewan; in Current Research2000-C13, Geol. Surv. Can., p1-10.

Corrigan, D., Maxeiner, R.O., and Harper, C.T. (2001): Preliminary U-Pb Results from the La Ronge–Lynn LakeBridge Project; in Summary of Investigations 2001, Volume 2, Saskatchewan Geological Survey, Sask. EnergyMines, Misc. Rep. 2001-4.2, p111-115.

Delaney, G., Jankovic, Z., MacNeil, A., McGowan, J., and Tisdale, D. (1997): Geological investigation of theCourtenay Lake–Cairns Lake Fold Belt and the Hills Lake Embayment, Johnson River Inlier, WollastonDomain, Saskatchewan; in Summary of Investigations 1997, Saskatchewan Geological Survey, Sask. EnergyMines, Misc. Rep. 97-4, p90-102.

Hulbert, L.J. (1989): Metallogeny of mafic and ultramafic rocks of the Trans-Hudson Orogen of northernSaskatchewan and Manitoba; in Investigations by the Geological Survey of Canada in Manitoba andSaskatchewan during the 1984-89 Mineral Development Agreements, Geol. Surv. Can., Open File 2133, p56-63.

Lafrance, B. and Varga, M. (1996): Structural studies of the Parker Lake Shear Zone and the Reilly Lake ShearZone, Reindeer Lake; in Summary of Investigations 1996, Saskatchewan Geological Survey, Sask. EnergyMines, Misc. Rep. 96-4, p119-124.

Lewry, J.F. (1976): Reindeer Lake North (SW quarter) area: Reconnaissance geological mapping of 64E-3, -4,and -6; in Summary of Investigations 1976 by the Saskatchewan Geological Survey, Sask. Dep. Miner.Resour., p29-35.

Lewry, J.F, Roberts, K., and Rees, C.J. (1980): Geology of the Area Around Spalding Lake; Sask. Miner. Resour.,Rep. 199, 18p.

Lewry, J.F., Thomas, D.J., Rees, C.J., and Roberts, K. (1981): Geology of an Area Around Compulsion Bay,Wollaston Lake; Sask. Miner. Resour., Rep. 205, 27p.

Macdonald, R. and Thomas, M.W. (1983): Compilation Bedrock Geology, Reindeer Lake North, NTS area 64E;Sask. Energy Mines, Rep. 232, 1:250 000 scale map with marginal notes.

MacDougall, D.G. (1984): Metallogenic Map Series, Reindeer Lake North, NTS area 64E; Sask. Energy Mines,Rep. 239, 1:250 000 scale map with marginal notes.

__________ (1987): Bedrock geological mapping Campbell River area (part of NTS 64E-6); in Summary ofInvestigations 1987, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 87-4, p34-45.

__________ (1988): Note on the occurrence of Campbell River Group metasediments between Campbell Lake andHighway 902 (part of NTS areas 64E-4 and -6); in Summary of Investigations 1988, Saskatchewan GeologicalSurvey, Sask. Energy Mines, Misc. Rep. 88-4, p67-69.

MacNeil, A., Delaney, G.D., and Ansdell, K. (1997): Geology of the Courtenay Lake Formation in the Cook Lakearea, Wollaston Domain, Saskatchewan; in Summary of Investigations 1997, Saskatchewan Geological Survey,Sask. Energy Mines, Misc. Rep. 97-4, p115-120.

Maxeiner, R.O., Gilboy, G.F., and Yeo, G.M. (1999): Classification of metamorphosed clastic sedimentary rocks: Aproposal; in Summary of Investigations 1999, Saskatchewan Geological Survey, Sask. Energy Mines, Misc.Rep. 99-4.1, p89-92.

Money, P.L. (1965): The Geology of the Area Around Needle Falls, Churchill River, Saskatchewan; Sask. Dep.Miner. Resour., Rep. 88, 70p.

Ray, G.E. (1975): Geology of the Foster Lake (northeast) and Geikie River (southeast) area; in Summary ofInvestigations 1975, Sask. Dep. Miner. Resour., Misc. Rep. 75-4, p13-18.

Saskatchewan Geological Survey 24 Summary of Investigations 2002, Volume 2

__________ (1980): Geology of the Parker Lake–Nelson Lake Vicinity; Sask. Dep. Miner. Resour., Rep. 190, 40p.

Ray, G.E. and Wanless, R.K. (1980): The age and geological history of the Wollaston, Peter Lake and Rottenstonedomains in northern Saskatchewan; Can. J. Earth Sci., v17, p333-347.

Rayner, N.M., Stern, R.A., and Bickford, M.E. (in review): Tectonic implications of new SHRIMP and TIMS U-Pbgeochronology of rocks from the Sask Craton, Peter Lake Domain, and Hearne margin, Trans-Hudson Orogen,Saskatchewan; Can. J. Earth. Sci.

Saskatchewan Geological Survey (1994): Geology and Mineral Resources of Saskatchewan; Sask. Energy Mines,Misc. Rep. 94-6, 99p.

Scott, B.P. (1969): The Geology of the Beckett Lake Area, Saskatchewan; Sask. Dep. Miner. Resour., Rep. 122,36p.

__________ (1970): The Geology of the Combe Lake Area, Saskatchewan; Sask. Dep. Miner. Resour., Rep. 135,32p.

Stauffer, M.R. and Lewry, J.F. (1993): Regional setting and kinematic features of the Needle Falls Shear Zone,Trans-Hudson Orogen; Can. J. Earth Sci., v30, p1338-1354.

Stauffer, M.R., Langford, F.F., Coleman, L.C., and Mossman, D.J. (1980): Geology of the Reindeer Lake North(southeast) Area; Sask. Dep. Miner. Resour., Rep. 200, 21p.

Stauffer, M.R., Fumerton, S.L., Langford, F.F., Coleman, L.C., and Mossman, D.J. (1981): Geology of the BallentinIsland Vicinity, Reindeer Lake; Sask. Dep. Miner. Resour., Rep. 206, 22p.

Streckeisen, A. (1976): To each plutonic rock its proper name; Earth Sci. Rev., v12, p1-33.

Tyrell, T.B. and Dowling, D.B. (1896): Report on the country between Athabasca Lake and the Churchill River;Can. Geol. Surv. Ann. Rep. (new series), v8, Rep. D.

Van Schmus, W.R., Bickford, M.E., Lewry, J.F., and Macdonald, R. (1987): U-Pb geochronology in the Trans-Hudson Orogen, northern Saskatchewan, Canada; Can. J. Earth Sci., v24, p407-424.

Weeks, L.J. (1941): Spalding Lake, northern Saskatchewan (map with marginal notes); Can. Geol. Surv., Map 59A.