Geochemistry and age of the Aillik Group and associated plutonic rocks, Makkovik Bay area, Labrador: implications for tectonic development of the Makkovik Province

Abstract

The

Field relations, geochemistry, and age of Paleoproterozoic igneous rocks in the northeastern Kaipokok Bay area, Makkovik Province, Labrador

“…1b). These units have been intruded by large granitoid plutons of the 1895-1870 Ma Island Harbour Bay Plutonic Suite, interpreted to have been emplaced in an Andean-type setting during dextral transpression, as well as scattered younger plutons (e.g., Ermanovics 1993;Kerr 1994;Kerr et al 1996Kerr et al , 1997Culshaw et al 2000;Barr et al 2001;Ketchum et al 2002).…”

“…1). The contact between the Aillik Group and the Post Hill Group (formerly Lower Aillik Group; Ketchum et al 2002) of the Kaipokok domain is highly tectonized within the Kaipokok Bay shear zone, and stratigraphic relations cannot be demonstrated (Kerr et al. 1996(Kerr et al.…”

“…1a, b;Culshaw et al 2002). The Aillik domain is dominated by metavolcanic and metasedimentary rocks of the Aillik Group (formerly Upper Aillik Group; Ketchum et al 2002) (Fig. 1).…”

“…In the type area around Makkovik Bay, the Aillik Group has been interpreted to consist of an earlier, dominantly sedimentary sequence, including arkosic sandstone, bedded tuff, siltstone, conglomerate, and minor mafic to felsic volcanic rocks, and a younger, dominantly volcanic sequence of dacitic to rhyolitic tuffs and flows with minor volcaniclastic sedimentary rocks (Bailey 1981;Gandhi et al 1969;Gandhi 1978;Gower et al 1982;Gower and Ryan 1987;Kerr 1994;Sinclair et al 2002). However, in the light of her new mapping, Hinchey (2007b) noted that it is unlikely that the concept of early and late sequences is valid.…”

“…1). Geological mapping and structural, chronological, and petrological studies were done in coastal parts of the Makkovik Province in the late 1990s as part of supporting geoscience projects related to the offshore Lithoprobe ECSOOT transect (e.g., Hall et al 1995;Ketchum et al 1997Ketchum et al , 2001aKetchum et al , b, 2002Culshaw et al 2000;Barr et al 2001;Sinclair et al 2002). The petrological studies focused on the Island Harbour Bay area of the Kaipokok domain (Barr et al 2001) and on the Makkovik area of the Aillik domain , but petrological data from igneous and metaigneous units in the intervening northeastern Kaipokok Bay area (Fig.…”