Te Tehery-Wager Geoscie ience Proje ject: Fin indings from the 20 2015 bedrock mappin ing campaign Holly Steenkamp, Canada-Nunavut Geoscience Office Natasha Wodicka, Geological Survey of Canada Christopher Lawley, Geological Survey of Canada Tony Peterson, Geological Survey of Canada Carl Guilmette, Université Laval
The Tehery-Wager Project Regional geoscience initiative: • Targeted bedrock mapping • Surficial geology mapping • Targeted stream sediment surveys Collaborative project: • Geological Survey of Canada (GEM 2 - South Rae Activity) • Canada-Nunavut Geoscience Office (SINED) Contributions from: • Université Laval • University of New Brunswick • Dalhousie University • Université du Québec à Montréal • University of Victoria • Nunavut Arctic College Duration: • 2 field seasons (2015/2016 ), outputs through ̴ 2019
Project Location Davis Strait Hudson Bay
Mapping prior to 2015 … • Reconnaissance mapping • Wright, 1955 • Lord and Wright, 1967 • Heywood, 1967 • Gordon and Heywood, 1988 Daly Bay complex • Henderson et al., 1990 Wager Shear Zone • Panagapko et al., 2003 – RPM • New reconnaissance survey by the GSC in 2012 • McMartin et al., 2013 • Wodicka et al., in prep
Project Objectives 1) Characterize and define distinct units within the Archean gneiss • Define their relationships with overlying supracrustal rocks • Snow Island suite K-feldspar porphyritic monzogranite? 2) Document stratigraphy of supracrustal belts, determine depositional ages and environments • Correlations to other known sequences? 3) Determine the timing, extent and degree of metamorphism and deformation in the area related to the Snowbird Tectonic Zone and/or terminal collision of the Trans-Hudson Orogeny • Peak pressure/temperature of metamorphism, spatial distribution • Development of trans-lithospheric fault systems 4) Evaluate the economic potential of the area • Metal and carving stone potential? Diamond potential? • Do large-scale faults provide favourable environments for mineralization?
2015 Field Season • June 30 – Aug 2 • 14 field crew • 5 camp crew • 1 Bell 206 LR • Turbo Otter supply runs
2015 2015 Mapp apping
Archean Tonalite to Granodiorite • Biotite ± hornblende • Granitic injections that cut foliation and are subsequently deformed • Pods, lenses, rafts of mafic rocks (e.g. pyroxenite, diorite) and supracrustal rocks (e.g. amphibolite, calcsilicate) • Van Breemen et al., 2007: U-Pb zircon crystallization ages 2699 ± 11 Ma, 2701 ± 14 Ma • Compositional complexity and variability – likely more phases to identify
Archean Monzo- to Syenogranite • Contains biotite, magnetite, rare muscovite • Foliation defined by biotite, compositional layering • Cut by syenite dykelets that are subsequently transposed • Nature of contact with Archean tonalite-granodiorite is poorly exposed • Unknown age
K-Feldspar Porphyritic Monzogranite K-Feldspar Monzogranite Tonalite • Rapakivi texture, coeval gabbro/diorite phases • Similar characteristics to felsic plutonic rocks of the 2.6 Ga Snow Island suite • Mylonitic zone at contact to underlying orthogneiss
Supracrustal Rocks • Occur as panels between layers of Archean orthogneiss • Granulite-facies mineral assemblages with partial retrogression to amphibolite-facies phases • Include: • Sill-Bt quartzite (3.7-2.55 Ga detritus – Ferderber et al., 2013) • Grt-Bt±Sill±melt semipelite with local psammite and pelite layers • Grt-Cpx amphibolite
Supracrustal Rocks • Includes: • Garnetite • Iron formation • Ultramafic boudins • Calcsilicate • Rare marble
Ultrapotassic Intrusions • Zoned, bimodal intrusions with magma mixing textures • Well exposed plutonic bodies, only 1 minette dyke identified • Correlative with Christopher Island formation and Martel syenite? Cpx-Bt Syenite Phlg Clinopyroxenite Cpx Monzonite
Undeformed Granitic Rocks • Monzogranite to syenogranite dykes and sills • Homogeneous texture and mineralogy • Rare fluorite • Contain xenoliths of orthogneiss and paragneiss • Possibly correlative with felsic rocks of the 1.85-1.81 Ga Hudson suite
Economic Considerations • Stream sediment and till sample findings of McMartin et al. (2013) highlight locations for follow-up work: • Gossanous metasedimentary rocks – anomalous Ag, Au, Bi, Cu and presence of safflorite • Ultrapotassic intrusions – REE potential in most fractionated parts of the plutons • Diamond potential • Nanuq property (Peregrine Diamonds) • Carving stone
Thank you! • Hamlet of Chesterfield Inlet • Hudson Bay Helicopters • Ookpik Aviation • Polar Continental Shelf Program • Discovery Mining Also See: Wodicka et al., 2015 – GSC Open File 7970, 2015 field report McMartin et al., 2015 – Poster Session at Arena – 2015 Surficial mapping Coming Soon – Steenkamp et al., 2015 – CNGO Summary of Activities report
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