A geological province in northernmost Ellesmere Island, named Pearya by Schuchert (1923) and interpreted as the relict of a Precambrian borderland, is now regarded as an exotic continental fragment with an internal suture, i.e. as a composite terrane (Chapter 4). This chapter outlines its late Middle Proterozoic to Late Silurian record and briefly compares it with the records of the Franklinian and Caledonian mobile belts. Special emphasis is placed on Ordovician tectonic and plutonic events, which are important for the evaluation of Pearya’s relationships with these two regions.
Establishment of this history has been difficult because of sparse age control for the pre-Caradoc stratigraphic record, the effects of five orogenies, and partial ice cover. On first approach, Pearya is divisible into four major successions that differ in age and overall lithology (Fig. 9.2; for geographic names throughout this chapter see Fig. 9.1). Succession I includes sedimentary and(?) volcanic strata of uncertain age that have been deformed, metamorphosed in the amphibolite facies, and intruded by granitic plutons in late Middle Proterozoic time (1.0-1.1 Ga). Succession II, ranging in age from Late Proterozoic to Early Ordovician, consists mainly of “miogeoclinal” or “platformal” sediments (carbonates, quartzite, mudrock) with lesser proportions of mafic and siliceous volcanics, diamictite, and chert. Its concealed contact with succession I is tentatively interpreted as an angular unconformity. Succession III includes arc-type and(?) ocean floor volcanics, mudrock, chert, and carbonates, and has associated with it fault slices of ultramafic-mafic complexes of late Early Ordovician (Arenig) age. The faulted contact between
Figures & Tables
Geology of the Innuitian Orogen and Arctic Platform of Canada and Greenland
Fourteen chapters discuss regional stratigraphy by time intervals from Precambrian to Quaternary, while other chapters describe the geography, geomorphology, tectonics, geophysical characteristics, and resources of the region. A summary chapter includes geologic maps, structural cross-sections, a geotectonic correlation chart, a gravity map, and a location map for exploration wells in the Arctic Islands and northern Greenland. A wealth of additional information is contained on the nine accompanying plates.