U-Pb and Sm-Nd Isotopic Results from the La Ronge Horseshoe … · Saskatchewan Geological Survey 1 Summary of Investigations 2012, Volume 2 U-Pb and Sm-Nd Isotopic Results from the

Saskatchewan Geological Survey 1 Summary of Investigations 2012, Volume 2

U-Pb and Sm-Nd Isotopic Results from the La Ronge Horseshoe Project Area, Western Glennie Domain and Southern Rottenstone

Domain: Evidence for 2.22 to 2.52 Ga Detritus

Ralf O. Maxeiner, Nicole M. Rayner 1, and Bruce M. Eglington 2

Maxeiner, R.O., Rayner, N.M., and Eglington, B.M. (2012): U-Pb and Sm-Nd isotopic results from the La Ronge Horseshoe project area, western Glennie Domain and southern Rottenstone Domain: evidence for 2.22 to 2.52 Ga detritus; in Summary of Investigations 2012, Volume 2, Saskatchewan Geological Survey, Sask. Ministry of the Economy, Misc. Rep. 2012-4.2, Paper A-10, 16p.

Abstract Preliminary SHRIMP and conventional ID–TIMS U-Pb zircon analyses are reported for four samples collected from the western Reindeer Zone, as part of the Saskatchewan Geological Survey’s La Ronge Horseshoe bedrock mapping project. Two samples of feldspathic psammite from the Crew Lake assemblage, collected between Nemeiben Lake (Glennie Domain) and MacKay Lake (Rottenstone Domain), each yielded 58 zircon grains giving Paleoproterozoic to Neoarchean ages. Both gave distinct peaks at circa 1.87 Ga (60% of grains), which also represent the youngest reproducible detrital zircon ages, and broader peaks between 2.3 and 2.5 Ga, both of which compare well with age analyses obtained in a previous study of Rottenstone Domain sedimentary rocks. These results suggest that sedimentary rocks of the western Glennie Domain and eastern Rottenstone Domain have similar depositional ages of about 1.87 to 1.86 Ga, have a common history, and that their detritus was derived from mixed sources including the emerging Flin Flon–Glennie Complex and, possibly, the approaching Sask craton and/or other Archean–latest Paleoproterozoic crustal blocks within the Manikewan Ocean. Sm-Nd isotopic results are also consistent with this interpretation.

The Bell Bay monzodiorite, which cuts the potassic sedimentary succession of the Crew Lake assemblage, yielded an age of 1838 ±6 Ma and an εNd value of +2.22 (T=1860 Ma). Three xenocrysts, varying in age from 1.9 to 2.4 Ga, were obtained from the monzodiorite sample and were likely derived from the sedimentary rocks. A tonalite sample collected from Nemeiben Lake contains compositionally unusual zircon grains and provided inconclusive results, suggesting crystallization ages between 1.94 and 1.84 Ga. It yielded a negative εNd value of -2.27 (T=1860 Ma) and a TDM of 2.62 Ga.

Keywords: geochronology, Rottenstone Domain, Glennie Domain, Reindeer Zone, Trans-Hudson Orogen, Crew Lake assemblage.

1. Introduction The La Ronge ‘Horseshoe’ project is a multiyear, 1:20 000-scale bedrock mapping initiative that is aimed at studying lithotectonic relationships in an enigmatic part of the western Reindeer Zone, which hosts numerous gold and base-metal occurrences. Specifically, the project attempts to re-evaluate the transition between Paleoproterozoic rocks at the junction between the La Ronge, Kisseynew, and Glennie domains and investigate their relationship to, and timing of emplacement onto, the structurally underlying Sask craton, exposed in the Nistowiak and Hunter Bay tectonic windows (Chiarenzelli et al., 1998). At the opposite, western end of the circa 3500 km2 study area, the transition between rocks of the Glennie and Rottenstone domains will be investigated. As part of this systematic mapping of selected areas, which is designed to delineate undivided gneisses into volcanic, sedimentary and plutonic protoliths, geochemical and geochronological studies will help to determine protoliths, tectonic settings, and age constraints of the newly defined lithotectonic assemblages and plutons.

Mapping as part of the La Ronge Horseshoe project commenced in 2010 at Nemeiben Lake (Maxeiner and MacLachlan, 2010) and continued in the Bob Lake (Maxeiner, 2011) and Hebden Lake (Maxeiner and Kamber, 2011) areas the following year. Four samples for geochronology and Sm-Nd isotopic determinations were collected at Nemeiben Lake (Figure 1) and preliminary findings are reported in this paper.

There are no previous U-Pb zircon geochronological results for the immediate Nemeiben Lake area. Further northeast, in the MacKay Lake area approximately 50 km north of Nemeiben Lake (Figure 1), a number of

1 Natural Resources Canada, Geological Survey of Canada, 601 Booth Street, Ottawa, ON K1A 0E8. 2 Saskatchewan Isotope Laboratory, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2.


Figure 1 – Regional geology map of the southwestern Reindeer Zone, with an inset of the domain map of Saskatchewan; location for samples RM1001-5002 and -5003 are shown on this map; the other samples are included in the detailed geological map of Nemeiben Lake (Figure 2). Abbreviations: BLP, Bridgeman Lake pluton and LDP, Little Deer Lake pluton; index map abbreviations: FFD – Flin Flon Domain, GD – Glennie Domain, KD – Kisseynew Domain, LRD – La Ronge domain, MD – Mudjatik Domain, PLD – Peter Lake Domain, RD – Rottenstone Domain, WB – Wathaman Batholith, and WD – Wollaston Domain.

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$Elizabeth LakeCu Deposit

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#0749 $Anglo Cu-AuRouyn Deposit

RM1001-5003

RM1001-5002

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REINDEER

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GD

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SASK CRATON

KD

FFD

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Crew L

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BLP

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104°30'105°00'105°30'

55°4

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55°3

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Arkose, conglomerate (McLennan Group)

Psammite - pelite (conglomerate)-derived migmatite

Mafic-intermediate (felsic)volcanic rockAmphibolite, mafic volcanic-calc-silicate rock

Biotite-hornblende gneiss

Prefix: (K), La Ronge (L), and Rottenstone (R) domains

Glennie (G), Kisseynew

Wathaman Batholith

Mannville Group

Gabbro, diorite, ultramafic rock

Diorite, tonalite

Tonalite

Granite-granodiorite-tonalite, derived gneiss

Felsic orthogneiss - strongly foliated tonalite-granodiorite

AI

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Granite, quartz monzonite

ARCHEAN and PALEOPROTEROZOIC

$Selected mineral deposits (deposits with # refer to the Saskatchewan Mineral Deposits Index)

Settlement

Highway number

LEGEND

PALEOPROTEROZOIC

Sedimentary Rocks

bd

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Mylonitic orthogneiss

gt

Volcanic Rocks

WB

Plutonic Rocks and Rocks ofProbable Plutonic Derivation

Intermediate-felsic volcanic rock

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PHANEROZOIC

Little Deer Lake picnic site

Nemeiben Lake campground

0 10 20 305 km


previously published, low precision Pb evaporation dates (Kyser and Stauffer, 1995) provide general timing constraints on the emplacement of volcanoplutonic rocks and deposition of stratigraphically younger sedimentary rocks. An individual 207Pb/206Pb zircon age of 1880 ±5 Ma for dacitic volcanic rocks is interpreted as the time of volcanism in the area west of Hebden Lake (Figure 1). Another 207Pb/206Pb evaporation age of 1854 ±3 Ma was determined for the marginal dioritic phase of the Little Deer Lake pluton (Figure 1), which truncates tight to isoclinal D1 folds (Maxeiner and Sibbald, 1995a). This is identical to the U-Pb zircon age of the granodioritic margin of the Bridgeman Lake pluton (1854 ±4 Ma; Kyser and Stauffer, 1995), which is located 15 km to the northeast.

Some of the youngest rocks identified in the southern La Ronge and Kisseynew domains include an 1843 ±2 Ma aplite cutting McLennan Group arkoses in the North Lake area (L. Heaman, pers. comm., 1992) and the granitic central portion of the Little Deer Lake pluton, which yielded a 207Pb/206Pb evaporation age of 1837 ±5 Ma (Kyser and Stauffer, 1995). Samples from two conglomerate units in the MacKay-Hebden lakes area, using the 207Pb/206Pb evaporation technique, provided youngest detrital zircon ages of 1855 ±34 and 1829 ±4 Ma (Ansdell and Yang, 1995).

The La Ronge Horseshoe bedrock mapping project was initiated to help facilitate and focus renewed interest in gold and base-metal exploration, as well as to illustrate the 3-D architecture of a geologically complex region of the southwestern Glennie Domain. Establishing absolute age markers is essential in helping to decipher the geological history of polydeformed terrains. For this component of the project, the main focus was to determine the age and provenance of sedimentary rocks of the Crew Lake assemblage, as well as providing constraints on late plutonism and early deformation.

2. Local Geology of the Nemeiben Lake Area The geology of the Nemeiben Lake area, as described by Maxeiner and MacLachlan (2010), can be summarized as consisting of a highly strained >1.87 Ga mafic volcanoplutonic succession containing mafic, locally pillowed volcanic rocks, metre-scale gabbroic sills, and minor rhyolitic components (Figure 2). This same succession was also described in the Bob Lake (Maxeiner, 2011), and Hebden Lake (Maxeiner and Kamber, 2011) and Trade Lake (Maxeiner and Normand, 2009) areas and, based on the work at Hebden Lake, is informally referred to as the Freestone Lake assemblage. Based on folding of gabbroic xenoliths in a granodiorite pluton in the Trade Lake area, the Freestone Lake assemblage is interpreted to predate the 1864.4 ±2.1 Ma crystallization age determined for the granodiorite (Maxeiner et al., 2010) and appears to have experienced deformation prior to its incorporation into the arc-derived pluton.

At Nemeiben Lake, and further to the northeast in the Bob Lake area, the Freestone Lake assemblage is in structural contact with a predominantly psammopelitic to psammitic potassic succession here referred to as the Crew Lake assemblage (rocks formerly referred to as being within the ‘Crew Lake belt’; e.g., Lewry, 1984). The sedimentary rocks are cut by the extensive Nemeiben Lake tonalite-granodiorite intrusive complex and still younger kilometre-scale intrusions of porphyritic monzodiorite. The massive to very weakly foliated monzodiorite plutons, exposed in the Bell Bay (Nemeiben Lake) and Bob Lake areas, contain abundant sedimentary xenoliths that have been foliated and folded prior to having been inundated by the intrusion.

3. Results U-Pb geochronology was carried out using both Sensitive High-resolution Ion MicroProbe (SHRIMP) and conventional isotope-dilution–thermal ionization mass spectrometry (ID–TIMS) U-Pb geochronology at the Geological Survey of Canada in Ottawa. SHRIMP analytical procedures followed those described by Stern (1997), with standards and U-Pb calibration methods following Stern and Amelin (2003). U-Pb results are presented in Tables 1 and 2 (SHRIMP and TIMS respectively), with analytical details given in the footnotes.

a) Feldspathic Psammite, Glennie Domain, Southwest Reindeer Zone (Sample KM1001-002; GSC Lab Number z10520)

A unit of feldspathic psammite and minor interbedded psammopelite and quartzite forms part of a more extensive succession of psammite-pelite, exposed over tens of kilometres between Highway 102, western Nemeiben Lake, and northward towards the Churchill River (Figure 1). In detail, the feldspathic psammite, which is similar in lithological appearance and lithostructural position to the Crew Lake assemblage and is here interpreted to form part of it, is interlayered with a unit of migmatitic psammopelite (Figure 2), and this sedimentary succession is in structural contact with the Freestone Lake assemblage, interpreted to be older (Maxeiner and MacLachlan, 2010; Maxeiner and Kamber, 2011). Previous workers had suggested that the ‘Crew Lake sedimentary rocks’ were pre- to synvolcanic (Thomas, 1986; Thomas, 1993).


Figure 2 – Detailed geological map of the Nemeiben Lake area (excerpt from Maxeiner and MacLachlan, 2010); location of samples RM1001-5002 and -5003 are shown on Figure 1; remainder are shown on this figure.

Glacial drift

Syn- to Post-tectonic Intrusive Rocks

P - Granite pegmatite, granite

Gs - Syenogranite, leucogranite

Mdi - Monzodiorite (monzonite, quartz monzonite)

Nemeiben Lake Ultramafic Intrusion

NPx - Pyroxenite

NDn - Dunite

NWb - Websterite

NWl - Wehrlite

Lgd - Leucocratic orthogneiss

G - Granite (to granodiorite)

Gd - Biotite granodiorite

Gdg - Garnetiferous granodiorite gneiss

T - Biotite tonalite (-granodiorite)

Ga - Gabbro

Px - Pyroxenite

Crew Lake Assemblage

Ps - Feldspathic psammite (psammopelite, feldspathic quartzite)

Psp - Migmatitic feldspathic psammopelite (psammite)

Fv - Felsic volcanic rock

Iv - Intermediate volcanic and volcaniclastic rocks

Mvt - Trachytic mafic volcanic rock

Mva - Altered mafic volcanic rock

Mvc - Layered calc-silicate rock

Mvp - Pillowed mafic volcanic flow

Am - Amphibolite{

Intrusive Rocks Predating Main Deformation Event

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Zone of abundant intrusivetonalitic material

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Freestone Lake Assemblage

Nemeiben Lake Intrusive Complex

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Nemeiben Lake Campground

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Nemeiben Lake

Whitmore Island

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Angus Lake

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Bell B

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Nemeiben LakeCampground

Campground Road

HW 102

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Elizabeth Lake

MunroePeninsula

0 21 km3 4 5

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KM1001-002

RM1001-5005

RM1001-5004

RM1001-0033

55

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5°1

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61

25

00

0 m

N6

13

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m N

475000 m E 480000 m E 485000 m E

105°20' W

Saskatchewan G

eological Survey 5

Summ

ary of Investigations 2012, Volume 2

Table 1 – SHRIMP U-Pb data.

Feldspathic psammite (KM1001-002), Glennie Domain

Spot NameU

ppmTh

ppm232Th/238U

Yb ppm Hf ppm

ppmRad206

%com206

204/206

%err

208Pb*/206Pb*

%err

4corr207*/235

%err

4corr206*/238

%err

errcorr

4corr207*/206*

%err

204corr206Pb/238UAge

1err

204corr207Pb/206Pb

Age1err

%Dis-cor-dant

10520-12.1 89 98 1.14 171 7520 23 2.96 1.7E-3 10 0.3748 1.9 4.75 2.6 0.3069 1.2 0.443 0.112 2.3 1726 17 1837 42 6.910520-83.1 175 82 0.48 175 6275 49 0.09 5.4E-5 38 0.1449 2.4 5.04 1.2 0.3250 1.0 0.880 0.112 0.6 1814 17 1839 10 1.610520-84.1 36 12 0.33 66 6449 11 0.32 1.8E-4 23 0.0952 5.9 5.26 1.8 0.3389 1.4 0.765 0.113 1.2 1881 22 1841 21 -2.510520-59.1 209 101 0.50 196 8468 58 0.08 4.5E-5 33 0.1476 2.2 5.02 1.2 0.3232 1.1 0.910 0.113 0.5 1805 17 1844 9 2.410520-71.1 63 22 0.36 90 6781 18 0.11 6.4E-5 28 0.1034 4.7 5.21 1.4 0.3346 1.1 0.794 0.113 0.9 1861 18 1848 15 -0.810520-61.1 52 21 0.43 81 6404 15 0.50 2.9E-4 68 0.1365 4.5 5.24 2.8 0.3353 1.2 0.426 0.113 2.5 1864 19 1854 46 -0.610520-85.1 86 117 1.41 221 7613 25 0.08 4.7E-5 30 0.4260 2.2 5.23 1.4 0.3343 1.1 0.813 0.113 0.8 1859 18 1856 14 -0.210520-56.1 118 36 0.31 101 6547 22 4.20 2.4E-3 10 0.1313 3.3 3.41 3.4 0.2177 1.3 0.395 0.114 3.1 1270 15 1858 56 34.810520-17.1 60 25 0.43 89 6146 17 0.05 2.8E-5 251 0.1254 4.3 5.14 1.8 0.3283 1.3 0.751 0.114 1.2 1830 21 1858 21 1.7

10520-106.1 381 224 0.61 183 12722 73 0.29 1.6E-4 22 0.2028 4.1 3.49 1.6 0.2230 1.2 0.730 0.114 1.1 1298 14 1859 20 33.310520-40.1 41 16 0.40 74 6408 12 0.39 2.2E-4 33 0.1277 4.8 5.21 1.7 0.3327 1.2 0.663 0.114 1.3 1851 19 1859 24 0.510520-62.1 172 106 0.63 224 9849 49 0.36 2.1E-4 23 0.1818 2.0 5.22 1.3 0.3333 1.1 0.821 0.114 0.8 1855 18 1859 14 0.310520-57.1 181 68 0.39 189 8829 50 0.97 5.6E-4 14 0.1220 2.9 5.02 1.6 0.3197 1.1 0.681 0.114 1.1 1788 17 1861 21 4.5

10520-6.1 195 93 0.49 184 8924 55 0.02 1.1E-5 219 0.1423 2.2 5.14 1.2 0.3278 1.1 0.890 0.114 0.5 1828 17 1861 10 2.110520-94.1 95 64 0.70 145 9370 27 0.14 7.9E-5 25 0.2086 2.7 5.24 1.3 0.3336 1.1 0.832 0.114 0.7 1856 17 1863 13 0.410520-70.1 86 48 0.57 109 6047 24 0.03 1.8E-5 82 0.1684 3.4 5.09 1.3 0.3231 1.1 0.817 0.114 0.8 1805 17 1868 14 3.910520-93.1 149 138 0.96 306 8822 42 0.68 4.0E-4 18 0.2918 2.2 5.10 1.5 0.3236 1.1 0.702 0.114 1.1 1807 17 1868 20 3.710520-88.1 88 82 0.96 175 8485 25 0.20 1.1E-4 53 0.3006 3.4 5.26 1.7 0.3339 1.3 0.782 0.114 1.1 1857 22 1869 19 0.710520-63.1 60 21 0.36 93 6408 15 0.35 2.0E-4 30 0.1245 4.6 4.45 1.6 0.2821 1.1 0.694 0.114 1.2 1602 16 1871 21 16.210520-38.1 61 24 0.40 96 6407 17 0.02 1.3E-5 505 0.1284 4.5 5.14 1.6 0.3261 1.1 0.690 0.114 1.2 1819 18 1871 21 3.210520-87.1 132 57 0.45 173 8745 37 0.06 3.3E-5 108 0.1292 3.0 5.16 1.3 0.3267 1.1 0.831 0.114 0.7 1822 17 1871 13 3.0

10520-102.1 205 118 0.59 252 8315 57 0.08 4.7E-5 36 0.1759 1.9 5.07 1.2 0.3212 1.1 0.909 0.115 0.5 1796 16 1872 9 4.710520-9.1 217 176 0.84 194 8567 62 0.05 2.8E-5 34 0.2436 1.6 5.28 1.1 0.3342 1.0 0.923 0.115 0.4 1859 17 1874 8 1.0

10520-81.1 257 248 1.00 298 10327 74 0.10 6.0E-5 55 0.2991 1.4 5.29 1.3 0.3346 1.1 0.893 0.115 0.6 1861 18 1875 10 0.910520 48 1 72 33 0 47 96 6360 21 1 24 7 1E 4 21 0 1405 3 5 5 41 2 3 0 3418 1 2 0 505 0 115 2 0 1895 19 1876 36 1 210520-48.1 72 33 0.47 96 6360 21 1.24 7.1E-4 21 0.1405 3.5 5.41 2.3 0.3418 1.2 0.505 0.115 2.0 1895 19 1876 36 -1.210520-60.1 101 81 0.83 259 7953 28 -0.03 -1.6E-5 203 0.2590 2.4 5.15 1.3 0.3255 1.1 0.819 0.115 0.8 1817 17 1877 14 3.710520-45.1 91 34 0.38 109 6110 26 0.80 4.6E-4 27 0.1378 3.7 5.23 2.1 0.3300 1.2 0.579 0.115 1.7 1838 19 1878 30 2.410520-20.1 42 18 0.44 87 6390 12 -0.09 -5.1E-5 162 0.1269 5.6 5.18 1.9 0.3266 1.2 0.639 0.115 1.4 1822 19 1880 26 3.510520-27.1 43 17 0.40 73 6520 12 0.17 9.9E-5 29 0.1207 5.5 5.09 1.6 0.3204 1.2 0.730 0.115 1.1 1792 18 1883 20 5.610520-49.1 140 60 0.44 241 8116 40 0.10 6.0E-5 52 0.1331 3.5 5.25 1.3 0.3304 1.1 0.811 0.115 0.8 1840 17 1885 14 2.710520-35.1 59 24 0.42 100 6454 17 0.32 1.9E-4 35 0.1212 4.3 5.30 1.6 0.3325 1.2 0.711 0.115 1.2 1851 19 1888 21 2.210520-96.1 90 31 0.35 72 7044 26 0.17 9.5E-5 39 0.0937 4.0 5.35 1.3 0.3355 1.1 0.804 0.116 0.8 1865 18 1891 14 1.610520-11.1 2030 740 0.38 656 12795 696 2.95 1.7E-3 2 0.1173 1.6 6.37 1.5 0.3991 1.1 0.748 0.116 1.0 2165 20 1892 17 -17.0

10520-105.1 177 63 0.37 435 7764 51 0.00 --- 100 0.1065 2.7 5.32 1.1 0.3329 1.0 0.909 0.116 0.5 1852 17 1894 9 2.510520-95.1 377 85 0.23 444 11918 109 0.03 1.7E-5 26 0.0703 2.2 5.38 1.1 0.3359 1.0 0.954 0.116 0.3 1867 17 1897 6 1.9

10520-1.1 273 141 0.53 171 8396 71 0.21 1.2E-4 57 0.1541 2.5 4.90 1.4 0.3042 1.0 0.733 0.117 1.0 1712 16 1908 17 11.710520-77.1 113 63 0.58 295 8401 33 0.06 3.4E-5 34 0.1624 2.7 5.45 1.2 0.3377 1.1 0.877 0.117 0.6 1876 18 1912 11 2.210520-21.1 59 23 0.40 99 8374 20 0.03 1.9E-5 586 0.1167 4.1 7.18 1.7 0.3875 1.1 0.652 0.134 1.3 2111 20 2157 23 2.510520-72.1 23 14 0.65 52 8086 8 0.51 3.0E-4 59 0.1849 4.9 8.56 2.3 0.4276 1.3 0.566 0.145 1.9 2295 25 2290 33 -0.310520-74.1 240 168 0.72 229 11190 92 0.03 1.6E-5 220 0.2069 1.4 9.13 1.1 0.4440 1.1 0.924 0.149 0.4 2369 21 2336 8 -1.710520-22.1 149 240 1.66 511 7722 56 -0.04 -2.3E-5 30 0.4731 1.3 9.23 1.1 0.4411 1.1 0.926 0.152 0.4 2356 21 2365 7 0.510520-82.1 114 81 0.73 122 10442 42 0.82 4.8E-4 14 0.2165 2.1 8.89 1.3 0.4250 1.1 0.812 0.152 0.8 2283 21 2366 13 4.110520-50.1 57 49 0.89 172 11258 21 0.19 1.1E-4 55 0.2535 2.7 9.13 1.4 0.4355 1.1 0.800 0.152 0.8 2330 22 2368 14 1.9

10520-100.1 163 57 0.36 120 10203 62 0.08 4.6E-5 37 0.1114 2.4 9.37 1.2 0.4442 1.1 0.938 0.153 0.4 2370 22 2379 7 0.510520-4.1 114 90 0.82 225 11175 44 0.12 6.9E-5 50 0.2331 2.0 9.71 1.2 0.4555 1.1 0.888 0.155 0.6 2420 22 2397 9 -1.1

10520-51.1 181 83 0.47 221 9957 70 0.04 2.1E-5 133 0.1408 2.1 9.65 1.1 0.4512 1.1 0.921 0.155 0.4 2401 21 2404 8 0.210520-14.1 145 65 0.46 146 9596 56 0.02 8.7E-6 439 0.1337 2.1 9.71 1.2 0.4535 1.0 0.903 0.155 0.5 2411 21 2405 8 -0.310520-97.1 87 44 0.53 168 8767 33 0.11 6.4E-5 48 0.1501 3.0 9.45 1.3 0.4408 1.1 0.866 0.155 0.6 2354 22 2406 11 2.610520-52.1 68 25 0.37 124 10479 26 0.12 6.7E-5 37 0.1015 3.8 9.84 1.4 0.4504 1.2 0.890 0.158 0.6 2397 25 2439 11 2.110520-47.1 181 67 0.38 144 11359 73 0.41 2.4E-4 14 0.1088 2.1 10.37 1.1 0.4677 1.0 0.922 0.161 0.4 2473 21 2464 7 -0.4

10520-2.1 446 209 0.48 169 11543 156 0.27 1.6E-4 25 0.1378 2.6 9.19 1.4 0.4083 1.3 0.910 0.163 0.6 2207 24 2490 10 13.410520-90.1 115 30 0.27 113 10977 45 0.28 1.6E-4 38 0.0721 3.5 10.30 1.3 0.4549 1.1 0.847 0.164 0.7 2417 22 2500 11 4.0

10520-114.1 156 65 0.43 195 9422 64 1.18 6.8E-4 11 0.1194 2.4 10.85 1.3 0.4783 1.1 0.822 0.164 0.7 2520 22 2502 13 -0.910520-89.1 147 88 0.62 246 8528 58 0.06 3.5E-5 26 0.1766 2.0 10.36 1.1 0.4565 1.1 0.930 0.165 0.4 2424 21 2503 7 3.8

10520-108.1 125 70 0.58 275 8957 50 0.57 3.3E-4 17 0.1694 2.3 10.59 1.3 0.4665 1.1 0.856 0.165 0.7 2468 22 2504 11 1.710520-55.1 335 98 0.30 304 11821 131 0.34 2.0E-4 15 0.0874 2.2 10.34 1.1 0.4541 1.1 0.936 0.165 0.4 2413 21 2508 7 4.5

10520-109.1 117 48 0.43 134 9428 50 0.10 5.8E-5 40 0.1150 2.5 11.36 1.2 0.4979 1.1 0.924 0.165 0.5 2605 23 2512 8 -4.510520-46.1 138 70 0.52 133 10384 56 0.00 ---- 9999 0.1476 2.3 10.79 1.1 0.4692 1.1 0.931 0.167 0.4 2480 22 2526 7 2.2

Analytical details: IP611, 25µm spot, 4nA primary intensity, six scans.

Error in 206Pb/238U calibration 1.0% (included).Mass fractionation correction of 0.3% applied to 207/206 results based on measurement of secondary standard z1242 (accepted 207/206 ratio = 0.18292).

Layered muscovite psammite (RM1001-5003), Rottenstone Domain

Spot NameU

ppmTh

ppm232Th/238U

Yb ppm Hf ppm

ppmRad206

%com206

204/206

%err

208Pb*/206Pb*

%err

4corr207*/235

%err

4corr206*/238

%err

errcorr

4corr207*/206*

%err


1err

204corr207Pb/206Pb

Age1err

%Dis-cor-dant

10521-65.1 75 20 0.28 145 9815 20 0.34 1.9E-4 32 0.0781 5.2 4.86 1.6 0.3164 1.1 0.703 0.111 1.1 1772 17 1823 20 3.210521-9.1 249 59 0.24 492 8369 71 0.11 6.4E-5 26 0.0716 3.4 5.18 1.3 0.3327 1.1 0.903 0.113 0.5 1852 18 1846 10 -0.3

10521-20.1 115 36 0.32 152 10651 32 0.23 1.3E-4 54 0.0795 4.1 5.08 1.5 0.3263 1.1 0.713 0.113 1.1 1820 17 1848 20 1.710521-19.1 62 25 0.42 417 9187 17 0.18 1.1E-4 82 0.1174 4.7 4.94 1.8 0.3166 1.2 0.659 0.113 1.4 1773 19 1850 25 4.710521-37.1 188 52 0.29 248 10457 50 0.14 8.3E-5 68 0.0853 3.3 4.79 1.4 0.3066 1.1 0.773 0.113 0.9 1724 16 1851 16 7.810521-51.1 236 46 0.20 153 11028 63 -0.01 -4.5E-6 429 0.0599 3.2 4.88 1.2 0.3128 1.0 0.906 0.113 0.5 1754 16 1852 9 6.010521-21.1 126 34 0.28 169 11027 35 0.16 9.4E-5 95 0.0823 4.1 5.06 1.7 0.3231 1.1 0.655 0.114 1.2 1805 17 1857 23 3.2

10521-109.1 109 42 0.40 162 9772 30 0.08 4.5E-5 161 0.1103 3.4 5.09 1.5 0.3251 1.1 0.711 0.114 1.1 1815 17 1857 19 2.610521-69.1 230 114 0.51 463 9126 61 0.14 8.0E-5 32 0.1320 2.3 4.85 1.2 0.3095 1.0 0.881 0.114 0.6 1738 16 1857 10 7.310521-39.1 214 187 0.90 298 9178 60 0.08 4.3E-5 148 0.2713 1.7 5.11 1.4 0.3262 1.1 0.761 0.114 0.9 1820 17 1857 16 2.310521-93.1 83 22 0.27 147 9607 23 0.14 7.8E-5 32 0.0827 4.6 5.09 1.3 0.3252 1.1 0.812 0.114 0.8 1815 17 1858 14 2.610521-98.1 161 46 0.30 227 9119 45 0.11 6.2E-5 19 0.0871 3.4 5.08 1.2 0.3239 1.1 0.880 0.114 0.6 1809 17 1859 10 3.110521-52.1 112 35 0.33 181 8051 33 0.10 6.0E-5 70 0.0948 3.3 5.45 1.3 0.3480 1.1 0.815 0.114 0.8 1925 18 1859 14 -4.110521-80.1 484 199 0.42 365 10741 138 0.03 1.7E-5 46 0.1240 1.5 5.18 1.1 0.3306 1.0 0.958 0.114 0.3 1842 16 1859 5 1.110521-75.1 275 60 0.23 276 10232 76 0.16 9.2E-5 22 0.0566 3.4 5.06 1.2 0.3229 1.0 0.895 0.114 0.5 1804 16 1859 9 3.410521 84 1 288 186 0 67 608 9705 79 0 28 1 6E 4 21 0 0814 3 9 5 01 1 3 0 3194 1 2 0 892 0 114 0 6 1787 18 1862 11 4 710521-84.1 288 186 0.67 608 9705 79 0.28 1.6E-4 21 0.0814 3.9 5.01 1.3 0.3194 1.2 0.892 0.114 0.6 1787 18 1862 11 4.710521-10.1 96 24 0.26 214 11017 27 -0.03 -1.7E-5 92 0.0809 5.0 5.11 1.4 0.3250 1.1 0.815 0.114 0.8 1814 17 1863 14 3.010521-28.1 116 41 0.37 295 9199 32 -0.03 -1.8E-5 1 0.1161 3.8 5.06 1.3 0.3211 1.1 0.847 0.114 0.7 1795 18 1868 13 4.410521-64.1 392 192 0.51 285 10358 95 0.12 7.1E-5 35 0.1437 2.2 4.43 1.2 0.2812 1.1 0.899 0.114 0.5 1598 16 1868 10 16.310521-23.1 117 76 0.68 155 7454 33 0.00 ---- 70 0.1927 2.7 5.11 1.2 0.3244 1.1 0.862 0.114 0.6 1811 17 1869 11 3.610521-18.1 211 37 0.18 227 11061 61 0.03 2.0E-5 123 0.0527 3.9 5.27 1.2 0.3343 1.0 0.878 0.114 0.6 1859 17 1869 10 0.610521-87.1 248 131 0.55 784 7848 72 0.03 2.0E-5 27 0.1635 2.1 5.32 1.1 0.3374 1.0 0.916 0.114 0.5 1874 17 1870 8 -0.210521-88.1 130 79 0.63 152 9239 37 0.10 5.9E-5 20 0.1891 2.4 5.26 1.3 0.3335 1.1 0.890 0.114 0.6 1855 18 1871 10 1.010521-76.1 258 83 0.33 376 8511 72 0.00 ---- 3852 0.1006 2.6 5.15 1.2 0.3261 1.1 0.905 0.114 0.5 1820 18 1871 9 3.210521-16.1 175 48 0.29 295 8095 51 0.07 3.9E-5 29 0.0810 3.3 5.32 1.2 0.3363 1.0 0.893 0.115 0.5 1869 17 1874 10 0.310521-86.1 240 137 0.59 361 9646 60 0.57 3.3E-4 15 0.1656 2.1 4.65 1.3 0.2926 1.0 0.808 0.115 0.8 1654 15 1885 14 13.910521-45.1 547 522 0.99 433 8738 156 -0.02 -1.2E-5 109 0.2857 1.0 5.27 1.1 0.3313 1.0 0.949 0.115 0.3 1845 16 1886 6 2.510521-62.1 189 65 0.36 247 8763 53 0.08 4.4E-5 32 0.0989 2.8 5.18 1.2 0.3251 1.0 0.897 0.116 0.5 1814 16 1888 9 4.510521-25.1 223 240 1.11 314 9288 61 0.02 1.1E-5 32 0.3186 1.6 5.10 1.1 0.3197 1.0 0.910 0.116 0.5 1788 16 1890 9 6.110521-66.1 150 38 0.26 229 8548 42 0.46 2.7E-4 21 0.0906 2.9 5.18 1.3 0.3238 1.1 0.789 0.116 0.8 1808 17 1895 15 5.210521-90.1 129 70 0.56 173 10293 37 -0.01 -5.2E-6 1204 0.1636 2.6 5.38 1.4 0.3359 1.1 0.756 0.116 0.9 1867 17 1898 17 1.9

10521-105.1 161 64 0.41 444 10035 43 0.77 4.4E-4 15 0.1250 2.7 5.02 1.4 0.3106 1.1 0.744 0.117 0.9 1743 16 1915 17 10.210521-22.1 137 58 0.43 209 9434 40 -0.16 -9.0E-5 52 0.1299 3.1 5.47 1.4 0.3371 1.2 0.827 0.118 0.8 1873 19 1922 14 3.010521-24.1 188 110 0.61 332 8737 52 0.02 8.9E-6 57 0.1779 2.3 5.26 1.2 0.3237 1.0 0.894 0.118 0.5 1808 17 1924 9 6.910521-48.1 323 73 0.23 312 10211 63 0.45 2.6E-4 16 0.1023 2.1 3.83 1.2 0.2285 1.0 0.864 0.122 0.6 1327 12 1980 11 36.410521-79.1 44 69 1.61 303 8863 15 0.11 6.1E-5 53 0.4913 2.5 8.16 1.9 0.4067 1.6 0.868 0.146 0.9 2200 30 2294 16 4.910521-71.1 224 112 0.52 175 9597 80 0.08 4.5E-5 30 0.1474 1.9 8.45 1.1 0.4165 1.0 0.936 0.147 0.4 2244 20 2314 7 3.610521-38.1 240 136 0.59 228 10981 86 0.03 2.0E-5 25 0.1713 1.8 8.50 1.1 0.4184 1.1 0.944 0.147 0.4 2253 20 2316 6 3.2

Saskatchewan G

eological Survey 6

Summ

ary of Investigations 2012, Volume 2

Table 1 (continued) – SHRIMP U-Pb data.

Layered muscovite psammite (RM1001-5003), Rottenstone Domain (continued)

Spot NameU

ppmTh

ppm232Th/238U

Yb ppm Hf ppm

ppmRad206

%com206

204/206

%err

208Pb*/206Pb*

%err

4corr207*/235

%err

4corr206*/238

%err

errcorr

4corr207*/206*

%err


1err

204corr207Pb/206Pb

Age1err

%Dis-cor-dant

10521-8.1 487 251 0.53 415 11772 179 0.02 1.3E-5 29 0.1513 1.4 8.75 1.1 0.4282 1.1 0.971 0.148 0.3 2297 21 2326 5 1.510521-49.1 236 42 0.18 40 11588 87 -0.01 -6.7E-6 481 0.0540 5.0 8.82 1.2 0.4294 1.1 0.880 0.149 0.6 2303 21 2334 10 1.610521-72.1 21 23 1.10 147 8392 8 0.68 3.9E-4 31 0.3290 3.9 9.03 2.0 0.4328 1.3 0.655 0.151 1.5 2318 26 2361 26 2.110521-56.1 153 67 0.45 128 10040 59 0.00 ---- 3427 0.1317 2.3 9.43 1.1 0.4457 1.1 0.934 0.153 0.4 2376 21 2384 7 0.410521-54.1 354 147 0.43 202 10897 135 0.03 1.4E-5 53 0.1280 1.6 9.66 1.1 0.4453 1.0 0.965 0.157 0.3 2374 20 2427 5 2.610521-46.1 137 72 0.54 178 9916 54 0.08 4.9E-5 35 0.1538 2.1 10.13 1.2 0.4556 1.1 0.934 0.161 0.4 2420 22 2470 7 2.410521-61.1 152 66 0.45 215 8025 60 0.08 4.4E-5 90 0.1257 2.2 10.23 1.2 0.4597 1.0 0.903 0.161 0.5 2438 21 2470 8 1.5

10521-107.1 245 97 0.41 276 9962 97 0.17 9.9E-5 28 0.1175 2.5 10.28 1.1 0.4590 1.0 0.931 0.163 0.4 2435 21 2482 7 2.310521-106.1 612 199 0.34 381 10632 244 0.02 1.2E-5 36 0.0942 1.3 10.50 1.0 0.4643 1.0 0.981 0.164 0.2 2459 21 2498 3 1.9

10521-34.1 412 212 0.53 317 10174 154 0.06 3.3E-5 32 0.1441 1.9 9.86 1.1 0.4352 1.0 0.963 0.164 0.3 2329 20 2500 5 8.110521-15.1 101 73 0.74 233 7131 40 0.09 5.2E-5 51 0.2044 4.2 10.48 1.3 0.4604 1.1 0.876 0.165 0.6 2441 22 2509 10 3.210521-13.1 445 115 0.27 240 11189 186 0.05 2.8E-5 34 0.0807 1.8 11.12 1.2 0.4878 1.1 0.975 0.165 0.3 2561 24 2511 4 -2.410521-44.1 102 64 0.65 140 9118 41 0.15 8.7E-5 19 0.1845 2.3 10.65 1.2 0.4669 1.1 0.910 0.166 0.5 2470 22 2513 8 2.110521-50.1 110 50 0.47 178 9157 46 0.06 3.7E-5 32 0.1337 2.5 11.14 1.2 0.4829 1.1 0.921 0.167 0.5 2540 22 2531 8 -0.410521-74.1 235 99 0.44 196 9974 96 -0.01 -3.4E-6 379 0.1227 1.8 10.97 1.1 0.4742 1.0 0.955 0.168 0.3 2502 22 2535 5 1.610521-99.1 616 117 0.20 725 12082 264 0.01 7.6E-6 22 0.0559 1.7 12.14 1.1 0.4986 1.0 0.983 0.177 0.2 2608 22 2621 3 0.610521-77.1 203 148 0.75 366 8436 86 0.11 6.2E-5 31 0.2035 1.6 12.07 1.1 0.4910 1.0 0.941 0.178 0.4 2575 22 2636 6 2.810521-33.1 88 69 0.80 264 8467 39 -0.08 -4.4E-5 10 0.2332 2.3 13.37 1.2 0.5164 1.1 0.910 0.188 0.5 2684 24 2723 8 1.710521-29.1 40 19 0.49 118 9782 18 0.26 1.5E-4 32 0.1336 4.1 14.49 1.4 0.5311 1.2 0.843 0.198 0.8 2746 27 2809 12 2.8


E i 206Pb/238U lib ti 1 0% (i l d d)Error in 206Pb/238U calibration 1.0% (included).Mass fractionation correction of 0.3% applied to 207/206 results based on measurement of secondary standard z1242 (accepted 207/206 ratio = 0.18292).

Bell Bay monzodiorite (RM1001-5005), Glennie Domain

Spot Nameppm

Uppm

Th232Th/238U

Yb ppm Hf ppm

ppmRad206

%com206

204/206

%err

208Pb*/206Pb*

%err

4corr207*/235

%err

4corr206*/238

%err

errcorr

4corr207*

/206*%

err

204corr206Pb/238U

Age1err

204corr207Pb

/206PbAge

1err

%Dis-cor-dant

10519-95.1 297 50 0.17 202 10326 84 0.38 2.2E-4 21 0.0498 4.0 5.03 1.7 0.3293 1.4 0.833 0.1108 0.93 1835 22 1813 17 -1.410519-118.1 359 66 0.19 211 10102 100 0.32 1.8E-4 32 0.0530 3.6 4.96 1.4 0.3248 1.1 0.764 0.1108 0.89 1813 17 1813 16 0.010519-113.1 292 59 0.21 157 10348 82 0.07 4.2E-5 21 0.0638 3.6 5.03 1.2 0.3278 1.1 0.882 0.1114 0.57 1828 17 1822 10 -0.310519-111.1 310 58 0.19 142 10352 89 0.23 1.3E-4 26 0.0557 3.7 5.10 1.4 0.3320 1.2 0.864 0.1114 0.70 1848 19 1823 13 -1.610519-125.1 180 34 0.19 123 9825 53 0.16 9.3E-5 34 0.0588 4.3 5.26 1.3 0.3424 1.1 0.821 0.1115 0.76 1898 18 1823 14 -4.710519-124.1 277 57 0.21 153 10719 78 0.15 8.8E-5 29 0.0596 3.7 5.03 1.2 0.3268 1.1 0.855 0.1116 0.65 1823 17 1826 12 0.2

10519-94.1 149 24 0.17 106 10704 42 0.11 6.4E-5 27 0.0453 7.1 5.00 1.5 0.3245 1.2 0.778 0.1116 0.97 1812 19 1826 18 0.910519-127.1 302 56 0.19 146 10481 87 0.56 3.2E-4 18 0.0543 3.6 5.16 1.4 0.3348 1.1 0.764 0.1118 0.90 1861 17 1829 16 -2.010519-120.1 272 58 0.22 180 10073 78 0.02 1.3E-5 99 0.0660 3.6 5.12 1.2 0.3318 1.1 0.877 0.1118 0.58 1847 17 1829 11 -1.110519-116.1 232 39 0.18 118 10485 69 0.14 8.2E-5 36 0.0505 4.4 5.33 1.3 0.3457 1.1 0.835 0.1119 0.73 1914 18 1830 13 -5.3

10519-91.1 275 56 0.21 194 9941 80 0.03 1.9E-5 0 0.0605 3.7 5.21 1.5 0.3372 1.3 0.921 0.1120 0.57 1873 22 1833 10 -2.510519-121.1 301 61 0.21 140 10420 87 0.05 2.8E-5 30 0.0590 3.7 5.20 1.2 0.3354 1.1 0.882 0.1124 0.57 1865 17 1839 10 -1.610519-119.1 356 67 0.19 156 10532 103 0.07 4.3E-5 40 0.0575 3.4 5.24 1.2 0.3380 1.1 0.886 0.1125 0.55 1877 17 1840 10 -2.3

10519-96.1 303 71 0.24 218 9675 87 0.20 1.1E-4 43 0.0673 3.4 5.17 1.5 0.3329 1.2 0.834 0.1127 0.81 1853 20 1843 15 -0.610519-114.1 254 43 0.18 115 10511 72 0.06 3.4E-5 35 0.0469 11.5 5.14 1.3 0.3309 1.1 0.860 0.1127 0.67 1843 18 1843 12 0.010519-117.1 333 69 0.21 187 9835 96 0.48 2.8E-4 17 0.0616 3.2 5.19 1.3 0.3340 1.1 0.803 0.1128 0.79 1858 17 1845 14 -0.810519-123.1 222 32 0.15 89 9927 65 0.05 2.9E-5 277 0.0430 5.0 5.27 1.6 0.3384 1.1 0.693 0.1130 1.16 1879 18 1847 21 -2.010519-130.1 271 47 0.18 177 10153 80 0.08 4.7E-5 37 0.0535 3.9 5.38 1.2 0.3447 1.1 0.873 0.1132 0.60 1909 18 1851 11 -3.610519-115.1 359 99 0.28 208 10428 105 0.08 4.7E-5 34 0.0823 2.8 5.30 1.3 0.3394 1.1 0.791 0.1133 0.82 1884 17 1852 15 -2.010519-126.1 262 56 0.22 133 10341 76 0.08 4.7E-5 39 0.0676 3.7 5.26 1.2 0.3364 1.1 0.861 0.1133 0.64 1869 17 1853 11 -1.0

10519-92.1 350 72 0.21 157 10501 99 0.23 1.3E-4 24 0.0589 3.3 5.16 1.2 0.3298 1.1 0.855 0.1134 0.64 1837 17 1854 12 1.010519-93 1 248 50 0 21 175 10065 71 -0 10 -5 9E-5 52 0 0619 4 0 5 25 1 4 0 3329 1 2 0 866 0 1145 0 69 1852 19 1872 12 1 210519-93.1 248 50 0.21 175 10065 71 -0.10 -5.9E-5 52 0.0619 4.0 5.25 1.4 0.3329 1.2 0.866 0.1145 0.69 1852 19 1872 12 1.210519-77.1 784 384 0.51 541 9808 237 0.05 2.7E-5 30 0.1470 1.5 5.65 1.1 0.3516 1.0 0.944 0.1166 0.36 1942 17 1905 7 -2.310519-91.2 115 93 0.83 223 10698 34 1.97 1.1E-3 15 0.2714 3.0 5.65 2.6 0.3404 1.2 0.481 0.1205 2.27 1888 20 1963 41 4.4

10519-116.2 24 23 0.96 110 10017 10 0.00 --- 100 0.2949 5.2 9.83 2.3 0.4597 1.7 0.744 0.1552 1.51 2438 34 2404 26 -1.7


Error in 206Pb/238U calibration 1.0% (included).No mass fractionation correction applied to 207/206 results.

Bell Bay tonalite (RM1001-5004), Glennie Domain

Spot Nameppm

Uppm

Th232Th/238U

Yb ppm Hf ppm

ppmRad206

%com206

204/206

%err

208Pb*/206Pb*

%err

4corr207*/235

%err

4corr206*/238

%err

errcorr

4corr207*

/206*%

err

204corr206Pb/238U

Age1err

204corr207Pb

/206PbAge

1err

%Dis-cor-dant

10522-25.2 9 0.00 0.00 247 97208 3 3.45 2.0E-3 108 -0.0057 25.7 17.72 8.3 0.3086 6.6 0.789 0.4163 5.10 1734 100 3969 76 63.710522-23.1 13 0.02 0.00 113 22378 4 1.56 9.0E-4 49 -0.0038 32.4 4.75 8.7 0.3443 2.4 0.280 0.1000 8.40 1907 40 1624 156 -20.210522-25.1 17 0.03 0.00 62 23119 5 1.09 6.3E-4 25 -0.0107 32.0 4.72 4.7 0.3213 3.4 0.716 0.1065 3.28 1796 53 1740 60 -3.710522-19.1 21 0.03 0.00 72 27674 6 -0.63 -3.6E-4 45 0.0170 52.4 5.45 3.3 0.3315 1.6 0.479 0.1191 2.89 1846 25 1943 52 5.810522-52.1 25 0.01 0.00 92 35836 7 1.22 7.1E-4 24 0.0034 20.5 6.80 3.4 0.3377 2.3 0.676 0.1460 2.48 1876 37 2299 43 21.210522-22.4 30 0.12 0.00 105 41650 9 1.61 9.3E-4 35 -0.0069 23.6 6.18 4.4 0.3511 1.9 0.424 0.1277 3.97 1940 31 2067 70 7.110522-22.2 31 0.02 0.00 110 43585 9 -0.23 -1.3E-4 319 0.0228 24.5 7.17 4.4 0.3566 1.6 0.365 0.1459 4.12 1966 27 2299 71 16.8

10522-3.1 55 0.5 0.01 187 37787 18 7.13 4.1E-3 10 -0.0119 4.9 8.75 4.1 0.3920 1.6 0.398 0.1619 3.74 2132 29 2475 63 16.310522-27.1 67 13 0.20 240 94427 20 0.73 4.2E-4 124 0.0575 8.3 12.58 3.1 0.3512 1.9 0.603 0.2598 2.46 1940 31 3245 39 46.310522-24.1 71 4 0.07 210 82441 21 -0.22 -1.3E-4 39 0.0342 14.5 10.75 2.1 0.3446 1.8 0.844 0.2263 1.13 1909 29 3026 18 42.510522-18.1 85 0.4 0.01 95 31033 28 0.10 5.6E-5 41 0.0034 21.5 6.89 1.6 0.3764 1.2 0.795 0.1327 0.95 2059 22 2134 17 4.110522-22.3 90 0.04 0.00 101 40273 27 0.20 1.2E-4 36 -0.0027 48.7 9.91 1.4 0.3516 1.1 0.797 0.2044 0.87 1942 19 2862 14 37.110522-34.1 97 0.06 0.00 102 40877 29 0.22 1.3E-4 19 -0.0010 29.1 9.52 1.6 0.3459 1.3 0.833 0.1995 0.87 1915 22 2822 14 37.010522-37.1 104 0.09 0.00 101 40089 32 0.34 2.0E-4 27 -0.0042 12.7 9.25 1.6 0.3558 1.3 0.814 0.1886 0.93 1962 22 2730 15 32.510522-35.1 108 0.04 0.00 102 40960 31 0.15 8.5E-5 141 0.0002 27.4 8.59 1.8 0.3385 1.4 0.779 0.1840 1.12 1880 23 2689 19 34.610522-22.1 110 0.03 0.00 103 40898 32 0.24 1.4E-4 20 -0.0045 37.3 8.69 1.8 0.3418 1.6 0.872 0.1843 0.89 1895 26 2692 15 34.110522 22.1 110 0.03 0.00 103 40898 32 0.24 1.4E 4 20 0.0045 37.3 8.69 1.8 0.3418 1.6 0.872 0.1843 0.89 1895 26 2692 15 34.110522-24.2 134 20 0.16 395 155041 40 0.70 4.1E-4 35 0.0343 7.9 14.03 1.8 0.3475 1.5 0.845 0.2927 0.94 1923 25 3432 15 50.610522-27.2 201 92 0.48 266 105234 61 0.25 1.4E-4 78 0.1343 3.6 10.01 1.8 0.3507 1.6 0.864 0.2070 0.93 1938 27 2882 15 37.8


Error in 206Pb/238U calibration 1.0% (included).No mass fractionation correction applied to 207/206 results.

Notes (see Stern, 1997):Spot name follows the convention x-y.z; where x = sample number, y = grain number and z = spot number. Multiple analyses in an individual spot are labelled as x-y.z.zUncertainties reported at 1 sigma and are calculated by using SQUID 2.22.08.04.30, rev. 30 Apr 2008.f206204 refers to mole percent of total 206Pb that is due to common Pb, calculated using the 204Pb-method; common Pb composition used is the surface blank (4/6: 0.05770; 7/6: 0.89500; 8/6: 2.13840).* refers to radiogenic Pb (corrected for common Pb).Discordance relative to origin = 100 * ((207/206 age -206/238 age)/(207Pb/206Pb age)).Calibration standard 6266; U = 910 ppm; Age = 559 Ma; 206Pb/238U = 0.09059.


Tabl

e 2

– TI

MS

U-P

b da

ta.

A sample of feldspathic psammite of the Crew Lake assemblage was collected on a lakeshore outcrop on a small island located north of Bell Bay on Nemeiben Lake (Figure 2). The rock is grey to brownish grey, fine grained, and equigranular. Compositional layering on a centimetre to decimetre scale is defined by variable mica content (Figure 3A). More mica-rich, psammopelitic layers in the vicinity of the sampled outcrop tend to contain variably transposed incipient partial melt, which gives those layers a gneissic appearance. Injected quartz±feldspar veins can account for up to 20% of the psammitic unit, and are commonly dismembered and transposed parallel to the compositional layering, although the sampled material was free of such veins and of partial melt. Compositionally, the feldspathic psammite contains quartz (25 to 50%), plagioclase (20 to 30%), abundant K-feldspar (10 to 30%), muscovite (1 to 10%), and biotite (5 to 10%); graphite and garnet are minor constituents. A feldspathic psammite (sample RM1001-0033) collected in close proximity to sample KM1001-002, yielded an εNd value of -0.37 (T=1860 Ma) with a depleted mantle model age (TDM) of 2346 Ma (Table 3). These numbers are comparable to those from samples of the Crew Lake assemblage of the eastern Rottenstone Domain further to the north (K. MacLachlan, pers. comm., 2011).

The feldspathic psammite was disaggregated using standard crushing/pulverizing techniques followed by density separation using the Wilfley table and heavy liquids. A limited number of zircon grains were recovered. They were typically colourless and ranged from clear to moderately turbid. The grains have a rounded or resorbed aspect, lacking sharp facets. In back-scattered electron (BSE) images, the clear zircon grains preserve broad to narrow oscillatory zoning; turbid grains are strongly altered (low BSE response) along high-U zones.

Fifty-eight zircons (Figure 4A) were analysed and yielded a range of ages between 1837 Ma and 2526 Ma. Of these grains, 50 were less than 5% discordant and used for plotting the data. The majority of the grains (n=30; 60%) indicate a dominant mode of circa 1.87 Ga. The remaining 20 grains yield sporadically distributed older ages between 2157 Ma and 2526 Ma, with a distinct cluster of seven analyses at circa 2.51 Ga, and two significant secondary peaks at about 2.40 Ga and 2.37 Ga. There is no correlation between morphology/zoning and age. No replicate analyses were conducted in order to precisely constrain the youngest detrital zircon, but the prominent mode at 1.87 Ga can be inferred as the maximum age of deposition of the psammite. No younger metamorphic rims were identified during imaging or documented during U-Pb analysis.

b) Layered Muscovite Psammite, Rottenstone Domain, Southwest Reindeer Zone (Sample RM1001-5003; GSC Lab Number z10521)

A sample of a layered muscovite psammite was collected from an extension of the Crew Lake

Bel

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(RM

1001

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460

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622

0.13

0.35

130.

003

0.61

530.

1161

0.00

2319

4126

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1896

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Figure 3 – Outcrop photographs of Crew Lake assemblage feldspathic psammite: A) sample KM1001-002, thin to medium bedded psammite; UTM 475091 m E, 6126997 m N, northwest of Bell Bay on central Nemeiben Lake and B) sample RM1001-5003, thin- to medium-bedded psammite; UTM 502680 m E, UTM 6139787 m N, along Highway 102 north of the Little Deer Lake picnic site, Figure 1. Note: all UTM coordinates are in NAD83, Zone 13v, unless otherwise stated.

assemblage (Figure 1) that cores a kilometre-scale antiform that extends northwest-ward from the Little Deer Lake pluton, past Highway 102 (Thomas, 1986; Maxeiner and Sibbald, 1995b) and through the Miles Lake area (Maxeiner, 2011) into low-grade rocks of the eastern Rottenstone Domain. The sample is from an area that is underlain by a fold- and/or fault-repeated section of the same sedimentary succession as that exposed on central Nemeiben Lake (see sample KM1001-002 location on Figure 1). The sample was collected to determine the detrital zircon age populations and, hence, provenance of the detritus, and to compare the results with samples previously collected from the Rottenstone Domain (MacLachlan et al., 2004; MacLachlan, 2005) and as part of the current project.

The sampled outcrop (Figure 3B) is characterized by intercalated layers of fine-grained psammite and psammopelite, with bedding on a 1 mm to 5 cm scale, containing variable proportions of muscovite and minor biotite. Some layers are ‘gritty’ with 1 to 2 mm quartzofeldspathic granules; other layers are quite quartz-rich and more resistant to weathering. Quartz veins are common on the outcrop, although care was taken to avoid these in the collection of the sample.

Sample processing was the same as for sample KM1001-002 described above; recovery of zircons was relatively poor, with the typically colourless grains ranging from clear to moderately turbid. Most grains are rounded or resorbed around the edges, lacking sharp facets. A unique feature of this sample is that many of the zircon grains contain relatively large inclusions (tens of microns) of an opaque unidentified mineral. In BSE images, the clear zircons preserve narrow oscillatory zoning, whereas the turbid grains are strongly altered (low BSE response) along high-U zones.

The detrital zircon profile of this sample is very similar to that of the feldspathic psammite sample (KM1001-002) (Figure 4A). Fifty-seven zircons were analysed and yielded a range of ages between 1.823 Ga and 2.809 Ga (Figure 4B). Only 46 of those grains are <5%

discordant and were used on the cumulative probability plot and histogram (Figure 4B). The majority of those grains (n=25; 54%) have a dominant mode of circa 1.86 Ga. The remaining 21 grains yield sporadically distributed older ages between 2.29 Ga and 2.81 Ga, with the majority of these grains (n=16; 34%) falling between 2.30 and 2.55 Ga. The prominent mode at 1.86 Ga gives a good indication of the maximum age of deposition for the psammite, although replicate analyses aimed at precisely constraining the age of the youngest detrital zircon were not conducted. Younger metamorphic rims were not identified during imaging or during U-Pb analysis.

Table 3 – Sm-Nd isotopic data for selected samples from the Nemeiben Lake area.

A

B

Sample Rock Type Sample Number Sm Nd Sm/Nd 147Sm/144Nd 143Nd/144Nd 2 sem 145Nd/144Nd 2 semƐNd (1860

Ma)TDM

(Ma)*

RM1001-0033 Feldspathic psammite RM1001-0033 5.008 27.12 0.1760 0.1116 0.511577 0.000015 0.348410 0.000012 -0.37 2346RM1001-5005 Bell Bay monzodiorite RM1001-5005 5.419 29.42 0.1755 0.1113 0.511706 0.000015 0.348414 0.000011 2.22 2151RM1001-5002 Trachytic diorite RM1001-5002 7.936 34.81 0.2172 0.1378 0.511964 0.000014 0.348413 0.000013 0.93 2381RM1001-5004 Bell Bay tonalite RM1001-5004 3.554 16.63 0.2037 0.1292 0.511696 0.000017 0.348410 0.000015 -2.27 2618* Model of Goldstein et al. (1984).


Figure 4 – Cumulative probability plots and histograms for feldspathic psammite samples of the Crew Lake assemblage. A) Sample KM1001-002 and B) sample RM1001-5003; for explanation see text.

c) Bell Bay Monzodiorite, Glennie Domain, Southwest Reindeer Zone (Sample RM1001-5005; GSC Lab Number z10519)

A sample of monzodiorite was collected on the northwest side of a 100 m x 50 m island (Figure 2), located north of Bell Bay on Nemeiben Lake, in order to provide a minimum age for deposition of the sedimentary rocks that it intrudes and to constrain the early deformation. The pluton, as described by Maxeiner and MacLachlan (2010), is >10 km long and 2 km wide and comprises homogeneous medium- to coarse-grained monzodiorite, grading locally into monzonitic and quartz monzonitic phases. The light grey rocks have a homogeneous, equigranular texture on weathered surface and are massive to very weakly foliated. Abundant xenoliths of folded sedimentary rocks (Figure 5A) derived from neighbouring units of feldspathic psammite and psammopelite, and lesser dioritic to gabbroic autoliths (Figure 5B), provide evidence for two folding events that have affected the supracrustal rocks prior to pluton emplacement (Maxeiner and MacLachlan, 2010). The randomly oriented(?) axial planes of F2 folds developed within sedimentary

xenoliths are locally overprinted by a weak northerly trending S3 fabric developed within the monzodiorite. The number of inclusions in the central zone of the intrusion is considerably less than in its marginal zones. The weak internal foliation present in most exposures of the intrusion is northerly striking and attributed to an F3 folding event. Late syenogranitic intrusions (unit Gs) and sets of intermediate and mafic dykes postdate the monzodiorite. Compositionally, the monzodiorite-quartz monzonite is characterized by abundant, partly subhedral to euhedral plagioclase (45 to 60%), hornblende (10 to 20%), K-feldspar (10 to 15%), biotite (5 to 10%), and quartz (0 to 10%). The determined εNd of the monzodiorite (Table 3) is relatively juvenile (+2.22, T=1860 Ma; TDM=2151 Ma), suggesting that interaction with crustal material was limited. A trachytic diorite (RM1001-5002; Table 3) collected along Highway 102 just north of MacKay Lake (Figure 1) and interpreted to be intrusive into circa 1.84 Ga McLennan Group rocks (Mullock Lake assemblage of Maxeiner and Balz, 2011) gave a similar εNd value (+0.93, T=1860 Ma, TDM=2381 Ma).

Although the sample material was visually free of xenoliths, the potential for xenocrysts was considered to be high based on the presence of xenoliths in all parts of the pluton. The preferred analytical method was, therefore, the ion probe. The sample was comminuted using Spark-2 electric pulse disaggregation (Rudashevsky et al., 1995). Sieving, followed by heavy liquid density separation of the fine-grained sieve separate was used to isolate zircon. Zircon recovery was excellent yielding abundant large, clear, colourless, prismatic grains. Concentric zoning of the zircon is visible in BSE images. Rare inclusions are present and the zircon grains are moderately fractured. Rare cores were observed in the BSE images.

RM1001-5003 , n=46/57, 95 to 105% conc.

0.000

0.002

0.004

0.006

0.008

0.010

0.012

0.014

1700

1800

1900

2000

2100

2200

2300

2400

2500

2600

2700

2800

2900

Age (Ma)

Pro

ba

bil

ity

0

1

2

3

4

5

6

7

8

9

Fre

qu

en

cy

KM1001-002 , n=50/58, 95 to 105% conc.

0.000

0.002

0.004

0.006

0.008

0.010

0.012

1700

1800

1900

2000

2100

2200

2300

2400

2500

2600

2700

2800

2900

Age (Ma)

Pro

ba

bil

ity

0

1

2

3

4

5

6

7

8

9

10

Fre

qu

en

cy

A

B

300 µ

300 µ


Figure 5 – Outcrop photographs of Bell Bay monzodiorite. A) Edge (dotted line) of a folded sedimentary xenoliths of the Crew Lake assemblage is inundated by the western margin of the Bell Bay monzodiorite pluton; note thin black lines drawn on monzodiorite to indicate the weak regional S3 foliation, which is at an angle to the F2 fold axis (dashed line) in the sedimentary xenoliths; B) monzodiorite sample location for RM1001-5005; note centimetre- to decimetre-sized gabbroic autoliths (arrows); UTM 476878 m E, 6129381 m N; and C) close-up of the monzodiorite shown in (B); note homogeneous, medium-grained texture of the massive monzodiorite.

Twenty-three zircon grains were analysed using the ion probe and yielded individual 207Pb/206Pb ages ranging from 1813 to 2404 Ma. Analyses of the majority of these grains form a single statistical population with a weighted mean 207Pb/206Pb age of 1838 ±6 Ma (n=22, MSWD=1.3), which we interpret as the crystallization age of the monzodiorite (Figure 6). This population of zircon commonly exhibits oscillatory zoning and has a Th/U ratio between 0.15 and 0.24 consistent with an igneous origin (Hoskin and Schaltegger, 2003). Three analyses from zircon cores yielded older 207Pb/206Pb ages of 1905, 1963, and 2404 Ma, and are interpreted to derive from xenocrystic grains. Rims of the dominant 1838 Ma age are documented on two of these grains.

d) Bell Bay Tonalite, Glennie Domain, Northwest Reindeer Zone (RM1001-5004; GSC Lab Number z10522)

An extensive plutonic complex of tonalitic to granodioritic composition underlies large parts of Nemeiben Lake (Maxeiner and MacLachlan, 2010; Figure 2). These medium- to coarse-grained rocks are generally homogeneous, and weather white, light grey to light pinkish grey. They are massive to moderately foliated, although local partial melt lends a gneissic texture. Biotite (5 to 10%) is the main mafic mineral in the pluton, with hornblende only occurring in minor concentrations in a few places. The tonalite-granodiorite complex contains abundant screens and kilometre-scale rafts of intermediate to mafic volcanic rocks, diorite, and gabbro. The plutonic complex is intruded by late granitic pegmatite dykes.

The sampled outcrop of Bell Bay tonalite (Maxeiner and MacLachlan, 2010) is a typical example of the granodioritic to tonalitic rocks of the Nemeiben Bay plutonic complex, although the sample was collected in an apophysis along the western margin of a large pluton where it is in intrusive contact with amphibolite derived from mafic volcanic rocks. The sample location contains isolated, strongly flattened amphibolite xenoliths (Figure 7A) in which the hornblende has been partially replaced by biotite. The tonalite sample is free of xenoliths, although it does contain some minor biotite schlieren, possibly representing digested sedimentary xenoliths or more completely altered amphibolite. Two foliations were observed in the sampled tonalite, suggesting that D2 and D3 deformation postdated emplacement. Determined εNd values for the rock (Table 3) are negative (-2.27; T=1860 Ma; TDM=2618 Ma), which may suggest that the tonalite represents a crustal melt, an interpretation generally consistent with its mineralogical makeup and textural appearance.

The sample was comminuted using electric pulse disaggregation (Rudashevsky et al., 1995). Sieving followed by heavy liquid density separation of the fine-grained separate was used to isolate zircon. Zircon recovery was excellent, yielding many large, well-faceted, prismatic grains. A few of the zircon grains are high quality, clear, colourless stubby prisms with rare inclusions/fractures. More predominant, however, is a

C

B

A


Figure 6 – Concordia plot for monzodiorite sample RM1001-5005; for explanation see text.

Figure 7 – Outcrop photographs. A) Partially lichen-covered exposure of Bell Bay tonalite at sample location RM1001-5005; note amphibolite xenolith (arrow); UTM 478527 m E, 6130497 m N; and B) close-up of tonalite at sample location; note well-foliated and leucocratic nature of these quartz-plagioclase-dominated rocks.

blocky, prismatic morphology exhibiting a distinct broad zonation parallel to the long direction of the zircon. These blocky zircon grains are colourless to pale orange-brown to medium orange-brown. In BSE images, the clear, colourless stubby prisms are typically unzoned or sector-zoned and have a low BSE response. The blocky elongate prisms exhibit a distinct high-contrast zoning not typically seen in BSE images of any other zircon, a rare phenomenon which would warrant further study.

Zircon of the Bell Bay tonalite exhibits unusual U-Pb systematics. The SHRIMP analyses are highly discordant with variable 207Pb/235U and 207Pb/206Pb ratios at relatively constant 206Pb/238U ratios (Figure 8A; Table 1). This is a result of unusually high (excess) 207Pb concentrations, which could be due to an anomalously enriched uranium composition with low

238U/235U ratios (i.e., 238U/235U accepted invariant value of 137.88). Such conditions can arise in a melt from natural fission reactions. Measurement of the 238U/235U in the zircon by ion probe determined a value within error of accepted uranium compositions, however, ruling out enriched uranium as the source of excess 207Pb. The unusual isotopic ratios could alternatively result from the incorporation of excess 231Pa, an intermediate daughter product of the 235U decay series, as has been documented by other workers elsewhere (Mortensen et al., 1992; Anczkiewicz et al., 2001). Incorporation of 231Pa during crystallization could cause excess 207Pb in zircon, although the excess 207Pb documented in zircon of the Bell Bay tonalite is much greater than that reported in these previous studies.

Instrumental error can also be ruled out as the cause of the anomalously high 207Pb concentrations (e.g., unaccounted isobars 3), as similar results were obtained using the TIMS technique (see below). In addition, Bell Bay tonalite

3 Isobars are atoms (nuclides) of different chemical elements that have the same number of nucleons. Correspondingly, isobars differ in atomic number (or number of protons), but not in mass number.

0.28

0.32

0.36

0.40

0.44

0.48

0.52

3 5 7 9 11

206P

b/2

38U

data-point error ellipses are 2s

25002500

23002300

21002100

19001900

17001700

RM1001-5005 GSC Lab number z105191838 ±6 Man=22 (red ellipses)MSWD = 1.3, probability = 0.18blue ellipses interpreted as inherited

300 µ

207Pb/235U

BA


Figure 8 – Concordia plots for sample RM1001-5004 (GSC lab number z10522). A) Plot of SHRIMP data with superimposed colour-coded Hf concentrations, illustrating the unusually high Hf values (normal is 8,000 to 15,000 ppm), observed in zircon from the tonalite; analyses of grains with lowest Hf concentrations are probably yielding the most accurate crystallization age (circa 1858 Ma), but these are imprecise because of low uranium contents, and B) three TIMS analyses (in blue) superimposed on the SHRIMP data (in white); one highly discordant, but precise grain yields an age of circa 1844 Ma, which is interpreted as the minimum crystallization age of the rock.

zircon contains between 20,000 and 150,000 ppm Hf, which is very high compared to more typical concentrations of 5,000 to 15,000 ppm (e.g., Andersen et al., 2002).

Given the unusual chemistry of the Bell Bay tonalite zircon, defining a unique age estimate is difficult. The weighted mean 206Pb/238U age derived from 16 of the 18 SHRIMP analyses (including the high Hf, strongly discordant grains) is 1916 ±21 Ma, (MSWD=2.2; probability of fit=0.006). The weighted mean 206Pb/238U age of a subset of four concordant, low Hf zircon grains (grains 23, 25,19, and 52; dark blue ellipses on Figure 8A) is 1858 ±34 Ma (MSWD=1.12, probability of fit=0.34).

To further constrain the age of the tonalite, TIMS results for two single-zircon fractions with extremely low U contents (0.5 and 1.2 ppm) were obtained and give imprecise, but relatively concordant 206Pb/238U ages of 1941 Ma and 1858 Ma (Table 2, Figure 8B). A higher U (22 ppm) zircon grain yielded a 206Pb/238U age of 1844 ±3 Ma, which is strongly discordant along the same trend as the ion probe data.

The geological significance of these SHRIMP and TIMS data is unclear. The most conservative interpretation of the results is that the Bell Bay tonalite crystallized sometime between 1.94 and 1.84 Ga. Further investigations into the lithology and chemistry of this rock are warranted. Although this sample was collected as being representative of an extensive granodiorite-tonalite complex, the highly unusual composition and isotopic systematics suggest a unique environment, likely not representative of the remainder of the tonalite-granodiorite plutons of the Nemeiben Lake area. Hafnium-rich zircon (compositions with extreme Hf enrichment are referred to as Hafnon) are reported mainly from rare earth element–bearing pegmatites (Wang et al., 1996; Claribourne et al., 2006, Chúdik et al., 2008).

1500

1700

2100

2300

0.24

0.28

0.32

0.36

0.40

0.44

0 4 8 12 16 20 24

20

6P

b/2

38U

207Pb/235U


Hf ppm

20,000

160,000

1500

1700

2100

2300

0.24

0.28

0.32

0.36

0.40

0.44

0 4 8 12 16 20 24

207Pb/235U


TIMS fraction 1844 +3 Ma

20

6P

b/2

38U

1900

A

B

1900


4. Discussion and Conclusions Two samples of sedimentary rocks were collected to constrain the age and provenance of a middle to upper amphibolite facies succession exposed between Nemeiben Lake and MacKay Lake (Figure 1) in the western Glennie Domain. Both samples yield interpreted maximum depositional ages of circa 1.87 Ga, with prominent modes of zircon at 1.87 Ga and between 2.30 and 2.55 Ga. These results are similar to those obtained from a psammite sample collected from the Crew Lake assemblage of the eastern Rottenstone Domain some 60 km to the north (K. MacLachlan, pers. comm., 2011), with which the Nemeiben Lake rocks have regional lithological continuity (Figure 1). These data, coupled with the potassic mineralogy and turbiditic nature of the sedimentary rocks, set them apart from the circa 1843 to 1830 Ma McLennan group and aluminous rocks of the circa 1855 to 1840 Ma Burntwood group. The provenance of the zircon detritus in the sampled Crew Lake assemblage appear to be 1.87 to 1.89 Ga volcanic rocks of the Reindeer Zone, as well as earliest Paleoproterozoic rocks, possibly from the Sask craton. This mixture of detritus may account for the -0.37 and -3.5 εNd values (at T=1860 Ma) and the corresponding TDMs between 2.3 and 2.5 Ga for the analyzed Crew Lake assemblage rocks (Table 3; K. MacLachlan, pers. comm., 2011). Absence of detritus related to <1.86 Ga successor arc plutons (e.g., Syme et al., 1998) suggests that the Crew Lake assemblage likely predated or was coeval with emplacement of these plutons. A marine depositional setting between the emerging circa 1.87 Glennie–Flin Flon complex and the Sask craton to the south is suggested. Detritus from the Hearne craton might be impeded due to the presence of an intervening trench/subduction complex to the west, although minor peaks at 2.81, 2.72, and 2.64 Ga may suggest subordinate input from Hearne craton sources (Figure 9).

Figure 9 – Schematic plate tectonic model for the southwestern Reindeer Zone at circa 1.86 Ga modified from Maxeiner et al. (2005, 2011). Abbreviations: LBA, 1.89 to 1.86 Ga Levesque Bay assemblage; LPA, ?1.89 Ga Lawrence Point assemblage; PBC, 1.91 Ga Porter Bay complex; RLA, 1.87 Ga Reed Lake assemblage; and SRC, 2.56 Ga Swan River complex.

Flin Flon -Glennie - Hanson

arc complex>1.87 Ga

Lawrence Point Ophiolite

Milton IslandMarginal Basin(2.83 to 1.86 Ga

detritus)

‘Successor arc’ plutons

(at depth)

Wathaman Batholith

1.865 to 1.85 Ga

Sask craton

Freestone Lakeoceanic crust

Park IslandBasin

Tectonicslices of 1.9 GaLevesque Bayoceanic crust

Hearnecraton

PBC and SRC remnants

RLA

LPA

LBA

Crew LakeMarginal Basin(2.81 to 1.86 Ga

detritus)

?

?

?

1860 Ma

Continental shelfsedimentation

Deep marinesedimentary basin

Island arc complexes

Subduction zone

Alluvial-fluvial and shallow watersedimentary basin

Arcplutonism

Oceanic crust

Thrust fault

Direction of sedimentation


The monzodiorite sample, which crosscuts the sedimentary rocks of the Crew Lake assemblage, yielded a crystallization age of 1838 ±6 Ma, with inherited grains of circa 1905, 1963, and 2404 Ma. The inherited ages are consistent with ages recorded in the sedimentary detritus of the Crew Lake assemblage, further confirming outcrop observations and intrusive relationships. Despite this apparent crustal contamination of the monzodiorite, its εNd value is relatively juvenile (+2.22), suggesting that the magma was mantle derived and likely did not ascend through thick continental crust. This would also suggest that the Bell Bay monzodiorite, which postdates the earliest deformation recorded by the Crew Lake assemblage, was emplaced into the Glennie–Flin Flon complex prior to its interaction with the Sask craton. It also implies that the southeastern Crew Lake assemblage had been deformed and accreted (marginal basin or accretionary prism?) to the southern side of the Glennie–Hanson–Flin Flon complex some time between 1.86 and 1.84 Ga (Figure 9). The monzodiorite itself appears to belong to a suite of late successor arc plutons of intermediate, felsic, and ultramafic composition that are widespread throughout the Reindeer Zone, some of which are locally referred to as the ‘boundary intrusions’ (e.g., Syme et al., 1998), and possibly attributable to renewed subduction processes, leading to the closure of the oceanic basin between the Sask craton and the Glennie–Hanson–Flin Flon complex.

A sample collected from the periphery of an extensive tonalite-granodiorite suite in Bell Bay of Nemeiben Lake yielded zircons with unusual compositions and U-Pb isotope systematics. Geochronological results from this sample were largely inconclusive, yielding a broad range for the timing of crystallization between circa 1.94 and 1.84 Ga.

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