QUATERNARY GEOLOGY STUDIES IN CENTRAL MELVILLE PENINSULA, NUNAVUT

Transcription

1 QUATERNARY GEOLOGY STUDIES IN CENTRAL MELVILLE PENINSULA, NUNAVUT Tremblay, T. 1, Paulen, R. 2 and Corrigan, D. 2 (1) Canada-Nunavut Geoscience Office, Iqaluit, NU (2) Geological Survey of Canada, Ottawa, ON tommy.tremblay@nrcan.gc.ca Carbonated till over Precambrian rocks

2 Partners Igloolik, NU This project is funded by the Geo-Mapping for Energy & Minerals (GEM) program ( ) and from the Canada- Nunavut Geoscience Office. Geological Survey of Canada-Ottawa Geological Survey of Canada-Québec Universities (Université du Québec à Montréal, Dalhousie) Hall Beach, Repulse Bay and Igloolik communities

3 Plan 1. Ice flow studies (summer 2009 field work) 2. Economic potential from till geochemistry (from Dredge, 1995, 2002, 2004 and 2009) 3. Lake sediments geochemistry (Day et al., 2009) 4. Future work and sample analysis

4 Highlights Glacial geology indicates different till types (coldbased, warm-based, shield, carbonated) which impact on glacial dispersal trains aspect An ice flow reversal is documented in the eastern part of the Peninsula From geochemistry in till and lake sediment -Prince Albert Gr. (PAG) show potential for Ni, Cu, Cr, V, Pb, Ag, Au, Mo -Penrhyn Gr. Show potential for Au, U, Pb, Zn, Mo

5

6 Study area and bedrock geology

7

8 Landsat image

9 DEM and till types Warm-based Warm-based Cold-based

10 Cold-based ice: extensive weathering of outcrops

11 Warm-based ice: ice moulded bedrock forms, with faint post-glacial weathering

12 Glacial geomorphology (Dredge, 1995, 2002)

13 Glacial striae

14 Striae synthesis

15 Ice flow history

16 Ice flow history

17 Ice flow history Late glacial ice divide

18 Ice flow reversal 2. (SE) 1. (NW)

19 Petrographic countings on till pebbles

20 Petrographic counting on till pebbles

21 Petrographic counting on till pebbles

22 2. Economic potential from till geochemistry (from Dredge, 1995, 2002, 2004 and 2009)

23 Bedrock geology and till types

24 Gossan localization (Dredge, 1995, 2002)

25 Ice flow on Melville Peninsula (Dredge, 2002)

26 Till geochemistry Ni

27 Till geochemistry Ni Ice flow for Melville north

28 Till geochemistry Cr

29 Till geochemistry Co

30 Till geochemistry Fe

31 Till geochemistry V

32 Till geochemistry Cu

33 Till geochemistry Pb

34 Till geochemistry Zn

35 Till geochemistry Au

36 Till geochemistry As

37 Till geochemistry Bi

38 Till geochemistry Sb

39 Till geochemistry Ag

40 Till geochemistry Mo

41 Till geochemistry U

42 3. Lake sediment geochemistry

43 Lake sediments Mafic deposits elements (Day et al., 2009)

44 Lake sediments Mafic deposits elements (Day et al. 2009) Till

45 Lake sediments Mafic deposits elements (Day et al. 2009) Till

46 Lake sediments Base metals deposits elements (Day et al., 2009)

47 Lake sediments Base metals deposits elements (Day et al., 2009) Till

48 Lake sediments Base metals deposits elements (Day et al., 2009) Till

49 Gold pathfinder elements (Day et al., 2009)

50 Gold pathfinder elements (Day et al., 2009)

51 Lake sediments Gold pathfinder elements (Day et al., 2009) Till As (2 um, ppm) Till As (63 um, ppm)

52 Lake Sediment Au (Day et al., 2009)

53 Lake Sediment U (Day et al., 2009)

54 Ni, Till (63 um) Summer 2009 till sampling (red dots), and Ni (orange bubbles)

55 Conclusions North-central Melville Peninsula 3 phases ice flow history: 1. NW W (LGM?), 2. W, converging to Garry Bay (deglacial), 3. SE, ice flow reversal to Foxe Basin (deglacial) Cold-based zone divided into total and intermediate zones, associated with reduction of ice flow transport distances, especially in total cold-based zone Glacial transport of erratics (PAG, carbonates) indicates preponderance of Phase 1 and 2 on the main plateau, and the lesser importance of Phase 3

56 Conclusions (suite) Principal anomalous zones, from till and lake sediments geochemistry W PAG Cu, Pb, As(Au?), Ag, Mo E PAG Ni, Cu, Cr, V, Au?, Fe Penrhyn Gr. U, Au, Pb, Zn, Mo From published HM in till data: Tremblay Lake area (kimberlites)

57 Future work Summer 2009 till samples: -HM geochemical analysis for base metals (Ni, Cu, Cr, Pb, Ag, Mo, PGE), focus on PAG -Gold grains counts in HM, focus on PAG -HM analysis for KIM, regional scale Summer 2010 field season: -Till sampling for HM analysis, focusing on Penrhyn Gr. most prospective areas (Au, U, Pb, Zn). -Detailled ice flow history for Melville south

58 Aknowledgements Linda Dredge (GSC-Ottawa, till geochemistry) Steve Day (GSC-Ottawa, lake sediments geochemistry) Melville Bedrock mapping crew, co-leaded by David Corrigan (GSC-Ottawa) and Léopold Nadeau (GSC-Quebec) Assistants: Benoît Soucy-De Jocas, Scott Robinson, Lindsay Richan. Universal Helicopter Newfoundland and Labrador Pierre Brouillette, Marco Boutin, Annick Morin, Celine Gilbert and Julien Paradis provided technical support with digital field data acquisition, GIS and IT. Linda Ham and Steve Sharpe (INAC) Assistants from Hall Beach community