The Hudson Submarine Canyon cuts across the continental rise in this sector. A chart contoured by Ivan Tolstoy and the authors from surveys made in 1949 is shown in Plate 2 (Ericson, Ewing, and Heezen, 1951). A series of 30 cross profiles is shown in Figure 17.
Figure 16.—Tracings of PDR records of continental and insular slopes
- (a). Insular slope of Madeira southwest of Funchal.
- (b). Continental slope of Europe.
- (c). Continental slope off northeastern United States.
The Hudson Canyon, which is more than 500 fathoms deep and 5 miles wide in the continental slope (Upper Gorge), narrows to less than 2 miles and shallows to 50 fathoms at the base of the continental slope. As it cuts across segment 2 of the upper continental rise the canyon gradually deepens. When it cuts into the upper part of segment 3 the canyon deepens to 300 + fathoms, widens to 3 + miles, and forms the Lower Gorge. The canyon gradually narrows and shallows as it cuts across the lower continental rise. It ends near Caryn Peak where sediment cores indicate an extensive delta or submarine alluvial cone. The upper continental rise and the lower continental rise can be tentatively traced northeastward through the Scotian Shelf and Grand Banks sectors. The irregular bench at 2250-2450 fathoms on W-6 and the bench at 2300 fathoms on W-8 and W-11 can probably be referred to segment 2 of the lower continental rise.
Near Cape Hatteras the entire character of the continental margin changes. Benches which were barely discernible farther north widen to form a series of broad steps which resemble a giant staircase descending to the depths of the Atlantic. These benches appear to merge with the benches of the Blake Plateau and Escarpment farther south. However, insufficient profiles exist to permit a firm correlation.
Figure 17.—Cross sections of Hudson Submarine Canyon