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TitleNueltin granites and mafic rocks in the Tebesjuak Lake map area, Nunavut: new geochronological, petrological, and geophysical data
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorPeterson, T D; Scott, J M J; Lecheminant, A N; Tschirhart, V LORCID logo; Chorlton, L B; Davis, W JORCID logo; Hamilton, M A
SourceGeological Survey of Canada, Current Research (Online) 2015-5, 2015, 23 pages, Open Access logo Open Access
PublisherNatural Resources Canada
Mediaon-line; digital
File formatpdf
AreaWharton Lake; Tebesjuak Lake; Tulemalu Bay; Mallery Lake
Lat/Long WENS-100.0000 -98.0000 64.0000 63.0000
Subjectsgeochronology; igneous and metamorphic petrology; geophysics; lead uranium ratios; uranium lead dates; radiometric dating; radiometric dates; bedrock geology; volcanic rocks; intrusive rocks; igneous rocks; rhyolites; tuffs; gabbros; granites; basalts; sedimentary rocks; conglomerates; sandstones; rhyodacites; amphibolites; migmatites; gneisses; metamorphic rocks; dykes; gabbros; Archean; alteration; petrography; petrographic analyses; geophysical interpretations; Nueltin Granites; Kivallliq Igneous Suite; McRae Lake Dyke; Pitz Formation; Mallery Complex; Fish Intrusion; Pamiutuq Intrusion; Precambrian; Proterozoic
Illustrationslocation maps; tables; plots
ProgramGEM2: Geo-mapping for Energy and Minerals Rae Province Project Management
Released2015 06 22
AbstractWe report new and refined legacy data on 1.77 to 1.74 Ga gabbros, basalts, and granites (Kivalliq Igneous Suite) in the Tebesjuak Lake map area (NTS 65-O). Uranium-lead (baddeleyite) ages for a coarse alkali gabbro at Mallery Lake (1769 ± 6 Ma) and for a subalkaline gabbro at the southwest-ern end of the McRae Lake dyke (1753.6 ± 1.2 Ma) were determined. Uranium-lead (zircon) ages of 1752.6 ± 4.1 Ma and 1746.7 ± 4.3 Ma were obtained for the Pamiutuq granite intrusion and a quartz-feldspar porphyry dyke, respectively. Gravimetric/magnetic modelling of the Mallery complex is con-sistent with a gabbroic ring dyke about 8 km in diameter and 1 km tall surrounding a granite core, with an underlying mafic sill or intrusive complex. Petrographic and geochemical data support a petrogenetic link between the Mallery gabbro, a coarse anorthosite body (Fish intrusion), and basaltic lavas in the map area, all of alkali basalt composition. These data indicate the presence of bimodal volcanism near the base of the Pitz Formation, and establish the oldest age of Kivalliq anorogenic igneous activity at ca. 1.77 Ga.
Summary(Plain Language Summary, not published)
The Tebesjuak Lake map area (NTS 65O), in Nunavut, is underlain by extensive intrusive and extrusive rocks of the Kivalliq Igneous Suite (Wharton Group, Nueltin Granite, and various mafic rocks). Spanning an age range of 1.74-1.77 billion years, these rocks are part of a broad anorogenic event that occurred throughout a large part of the western Churchill province. New geochemical, petrological, and geophysical data acquired during the GEM1-U project has now accurately established space-time trends in magma composition, the physical form of an important bimodal intrusion, and the relationship of Kivalliq rocks to some mineral showings in the map area.

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