Bedrock geology of the Nares Strait region of Arctic Canada and Greenland with explanatory text and GIS content

Onshore and offshore bedrock geological features of the Nares Strait region have been compiled on a new map at a scale of 1:1,000,000. The map includes onshore map units and structure of Nunavut in Arctic Canada from northern Baffin Island to northern Ellesmere Island and, on the Greenland side, from the Thule area to Nansen Land and the Lincoln Sea. Sources include published maps of the Geological Survey of Denmark and Greenland (GEUS) and the Geological Survey of Canada (GSC). Also introduced are draft maps of northeast Ellesmere Island currently in preparation as a result of co-ordinated field work from 1998 to 2000 by staff of the German Federal Institute for Geosciences and Natural Resources (BGR) and GSC. Offshore geology is drawn from the interpretation of geophysical data, most notably petroleum industry reflection profiles, and government reflection and refraction seismic and aeromagnetic data including new marine and airborne surveys acquired in 2001 and 2003 as a result of co-operative work involving GSC, BGR, the Danish Lithosphere Centre and the Canadian Coast Guard. Major features of the map area include 1) the Canada-Greenland shield subdivided into Archean gneissic terranes, high grade Paleoproterozoic supracrustal belts and plutonic igneous suites, 2) Mesoproterozoic sedimentary basins and related post-orogenic craton cover of Thule and Borden basins, 3) Mesoproterozoic through lower Paleozoic rocks of Pearya, a composite terrane on northern Ellesmere Island accreted to ancestral North America in the mid-Silurian, 4) Neoproterozoic to Devonian strata of the Franklinian succession, 5) Carboniferous to Cretaceous and younger strata of Sverdrup Basin erected on the erosional roots of the Upper Devonian-Lower Carboniferous Ellesmerian Orogen, and 6) Cretaceous through Neogene strata located in fault-bounded small basins that record the depositional history of Baffin Bay rifting and spreading, and contemporaneous strike slip faulting and thrusting in the Eurekan Orogen adjacent to Nares Strait. Offshore bedrock map units include 1) granitoid rocks and crystalline basement, 2) moderate velocity stratified successions assigned to either the mid-Proterozoic (Borden-Thule) or lower Paleozoic (Franklinian) packages, 3) refraction-identified oceanic crust (tectonized serpentinite?) and cover that underlies the abyssal plain of northern Baffin Bay; 4) Cretaceous-Neogene continental margin rift-fill and rift-cover sequences with low velocity and subdued magnetic signature, and 5) magnetically anomalous basin-fill in Nares Strait, correlated with upper Paleocene volcaniclastic sandstones exposed on northeastern Ellesmere Island.