Bedrock geology of the Ellice Hills map area and new constraints on the regional geology of the Committee Bay area, Nunavut

Abstract

The Ellice Hills map area (NTS 56 P), southwest of Committee Bay, contains two belts of Archean supracrustal rocks intruded by younger, diverse plutonic rocks. The Ellice Hills supracrustal strand is a west-northwest-facing belt of interbedded psammite, semipelite, silicate iron-formation, komatiite, and basalt. To the south, the Committee Bay supracrustal belt contains komatiite, semipelite, psammite, and iron-formation, overlain by quartzite, rare intermediate volcanic rocks, and interbedded psammite and semipelite. Ultramafic sills intrude the supracrustal rocks. Folded with the Archean supracrustal rocks is a small outlier of younger meta-arkose and calc-arenite. A regionally extensive, northeast-striking, 2610 Ma intrusive complex of K-feldspar-magnetite granodiorite and monzogranite intrudes supracrustal rocks in the south. To the north, the supracrustal belts are cut by tonalite, granodiorite, monzogranite, and diorite plutons that are likely part of a widespread, 2610-2580 Ma plutonic suite. The northern part of the Ellice Hills area is intruded by a large biotite-muscovite monzogranite pluton.

Origin and tectonometamorphic history of the Repulse Bay block, Melville Peninsula, Nunavut: exotic terrane or deeper level of the Rae craton?

“…These belts are ca. 2.97, 2.83, and 2.74-2.69 Ga in age (Zaleski et al 2001;Bethune and Scammell 2003;Skulski et al 2003;Wodicka et al 2011) and extend from north of Baker Lake to northern Baffin Island ( Fig. 1; e.g., Woodburn Lake group, Committee Bay belt, Prince Albert belt, Eqe Bay and Isotorq belts, etc.).…”

“…Mesoarchean crust has also been documented in other terranes and blocks of the Churchill Province, including the Sugluk block (2.97-2.82 Ga; Wodicka and Scott 1997;Rayner et al 2008), and the southern Hearne craton (3.1 Ga; van Breemen et al 2007b). The Mesoarchean orthogneissic rocks and the Archean supracrustal belts of the Rae craton and Chesterfield block are generally intruded by 2.73-2.67 Ga tonalitic to granitic plutons and on the mainland by voluminous 2.62-2.58 Ga, dominantly monzogranitic plutons (e.g., Hanmer et al 1994;Williams et al 2000;Bethune and Scammell 2003;Skulski et al 2003;Davis et al 2006;van Breemen et al 2007a;Dumond et al 2010;Hinchey et al 2011;Rayner et al 2011;Wodicka et al 2011).…”

“…Rae craton, Archean supracrustal sequences are composed of komatiite, mafic to felsic volcanic rocks, conglomerate, quartzite, pelite, and iron formation (e.g., Frisch 1982;Zaleski et al 2001;Bethune and Scammell 2003;Skulski et al 2003;Young et al 2007;Corrigan et al 2013). These belts are ca.…”

Neoarchean Mantle-derived Magmatism within the Repulse Bay Block, Melville Peninsula, Nunavut: Implications for Archean Crustal Extraction and Cratonization

“…2.55 Ga (Davis et al 2006). Collision was followed by 2.62-2.58 Ga 'I-type' dominantly monzogranitic plutonism (Skulski et al 2003;Davis et al 2006;van Breemen et al 2007;Rayner et al 2011) that has been described in areas as 'high-K' (Hinchey et al 2011).…”

“…The north-central segment of the Western Churchill Province is divided into two main crustal divisions, the Rae and Hearne cratons (Hoffman 1988). The Rae craton is made up of Mesoarchean to Neoarchean north-northwesterly trending granite-greenstone belts composed of komatiite, mafic and felsic volcanic rocks, conglomerate, quartzite, pelite, and iron formations (Frisch 2000;Zaleski et al 2001;Bethune and Scammell 2003;Skulski et al 2003;Corrigan et al 2013). Rare Mesoarchean to Neoarchean calc-alkalic gneiss complexes are sandwiched between the low grade belts (Zaleski et al 2001;Hartlaub et al 2005;Rayner et al 2013).…”