Geology of the Markham Bay-Crooks Inlet area, southern Baffin Island, Northwest Territories

Abstract

Metasedimentary rocks and orthogneisses of the Markham Bay-Crooks Inlet area comprise folded and imbricated panels of a broadly south-verging thrust þ fold belt subsequently affected by orogen-parallel folding and cross-folding. Two assemblages of supracrustal rocks have been identified: the more extensive shelf sequence comprises the marbles, psammites, and semipelites of the ca. 1.93-1.86 Ga Lake Harbour Group, the second is characterized by thick successions of feldspathic quartzite and pelite, interpreted as a foreland basin sequence and intruded by layered ultramafic-mafic sills. Several types of orthogneiss have been recognized: 1) layered hornblende tonalite and monzogranite gneiss imbricated with supracrustal units in the southern part of the area, and 2) orthopyroxene tonalite with diorite sheets in the central part of the area that is in part 1.84-1.82 Ga. The ca. 1.85 Ga Cumberland monzogranite batholith postdates earliest imbrication, but is itself carried by youngest thrusts.

Archean and Paleoproterozoic cratonic rocks of Baffin Island

“…Quartzite, marble, psammite and semipelite mapped on the eastern and western peninsulas of southern Baffin Island are lithologically similar to the metasedimentary strata of the contiguous Lake Harbour Group in its type locality of Kimmirut (Fig. 10;St-Onge et al, 1996Scott et al, 1997). Two lithologically and geographically distinct sequences can be recognized.…”

“…continental-margin clastic and carbonate-platform strata, overlain by a volcano-sedimentary rift package that includes iron-formation, and capped by deep-water turbidites (Partin et al, 2014a;Wodicka et al, 2014). To the south of the proposed suture lies the Lake Harbour Group, which grades basinward to the north and comprises a clasticcarbonate continental-margin sequence (Scott et al, 1997(Scott et al, , 2002a). Stratigraphic differences with the Piling Group include the presence of a basal orthoquartzite and the absence of iron-formation and greywacke.…”

“…Over much of southern Baffin Island, the Lake Harbour Group is composed of quartzite, garnetiferous psammite, minor semipelite and pelite, structurally overlain by laterally continuous to boudinaged bands of pale grey to white marble and calc-silicate rocks ('Kimmirut sequence'; Scott et al, 1997). In contrast, extensive garnetiferous psammite interlayered with pelite and/or semipelite, with less than 5% marble and calc silicate rocks ('Markham Bay sequence'; Scott et al, 1997), is exposed on the eastern islands and bluffs of Meta Incognita Peninsula, as well as in the Markham Bay area (Fig. 10).…”

Quantitative elemental mapping of granulite‐facies monazite: Textural insights and implications for petrochronology

“…Meta Incognita Peninsula is underlain by quartzite, marble, psammite and semipelitic units that are lithologically similar to the metasedimentary strata of the contiguous Lake Harbour Group in its type locality of Kimmirut (Scott, St‐Onge, Wodicka, & Hanmer, 1997; St‐Onge et al., 1996; Figure 2). Two lithologically and geographically distinct sequences can be recognized across the length of the peninsula.…”

“…Two lithologically and geographically distinct sequences can be recognized across the length of the peninsula. On the western peninsula, the Lake Harbour Group comprises quartzite, garnetiferous psammite, minor semipelite and pelite, overlain by laterally continuous to boudinaged bands of pale grey to white marble and calc‐silicate rocks (‘Kimmirut sequence’; Scott et al., 1997). In contrast, extensive garnetiferous psammite interlayered with pelite and/or semipelite, with less than 5% marble and calc silicate rocks (‘Markham Bay sequence’; Scott et al., 1997), is exposed on the eastern portion of the peninsula.…”