Geology of Labrador Shelf, Canada: ABSTRACT

Abstract

The area includes the shelf and continental slope of eastern Canada between north latitudes 50° and 67°. Water-depths average 450-800 ft. Some parts of the slope covered with as much as 6,000 ft of water are included. The area encompasses 200,000 sq mi (130 million acres). Mainland Labrador and southern Baffin Island are Precambrian in age. The land surface is an uplifted Cenozoic peneplane that is tilted away from the sea. The coastal area is fiord indented and rugged. In contrast, the shelf is underlain by soft Mesozoic and Cenozoic sedimentary rocks. The shelf is smooth and quite unlike the mainland. The boundary line between the young sediments and the Precambrian is mainly coincident with a submarine marginal channel near the shoreline, and parallel with it along the coast. Until the Triassic, Greenland and Canada were joined and some of the early Paleozoic seas covered the entire area. Perhaps part of the area was covered by late Paleozoic seas. The first manifestations of rifting probably were in the Triassic. Block faulting in the Early Jurassic made basins which started to receive marine sediments. It is not clear when new ocean floor formed in the Labrador Sea but certainly it was widespread in the middle Cretaceous and may have been present as early as Middle Jurassic. Sediments which crop out on the eastern part of the marginal channel and on the continental slope range in age from Jurassic to late Cenozoic. Climate during this time span was mostly subtropical to tropical. Jurassic and Cretaceous clastic sediments came from adjacent areas. Cenozoic sediments, which now cover the floor of the Labrador Sea, ware transported from central Canada by a river system which entered at Hudson Strait. The Mesozoic rifting controlled the early sedimentation patterns. First drilling targets will be associated with the horsts. Theoretically, the warmer water deposits of clastic rocks over and around fault blocks is ideal for the generation and accumulation of hydrocarbons. End_of_Article - Last_Page 2148------------