Marine Geology of Eastern Continental Margin of Canada: ABSTRACT

Abstract

The outer continental shelf of eastern Canada, from Georges Bank to Ellesmere Island, is mainly smooth compared with most of the land on the west. This submerged prairie ranges from 10 to 300 mi wide. It is the northern extension of the coastal plain of the United States that is partly exposed on land as far north as Long Island. North of Long Island there are no documented marine fragments of plain sediments on land. The depth of water on the banks south of 48°N lat. is about 200 ft. In contrast, north of the 48° parallel, the average water depth is about 450 ft. The shelf is partly covered with Pleistocene ground moraine. Cenozoic and Mesozoic rocks crop out or are close to in-situ positions along some of the submerged valleys. It has been known for decades that most of the submerged coastal plain is underlain by fairly low-velocity sediments up to 25,000 or more ft thick. It can be speculated that these fairly soft strata (low velocity) are not older than Triassic because drifting and rifting probably started to make basins available to be filled at that time. The beds are mainly sandstone and shale. The source areas on the west are Precambrian and the folded Paleozoic rocks of the Appalachians. One speculation is that the Precambrian perhaps yielded a sandier section than the Paleozoic rocks because of the dominance of carbonates, volcanics, and shales in the Appalachian area. Drilling on the Grand Banks and Sable Island has shown that hydrocarbons are present. It is known that almost all the stages are present from Pleistocene to Upper Jurassic. Salt is present but its age is still only assigned to the Jurassic or earlier. It is tempting to speculate that the salt is Permian and a western segment of the North Sea salt. Salt dome structures are present as are basement features. This large frontier area is an attractive place to look for large petroleum reserves. End_of_Article - Last_Page 860------------