Sediments and geomorphology of the continental shelf off southern New England

The Erie Interstade

“…At 18,000 to 20,000 yrs B.P., the first glacial maximum, their curve shows sea level at -90 to -55 m. This is definitely not in concordance with the extent of the continental ice sheets, and we therefore doubt that the position suggested for the first glacial maximum is correct. Garrison and McMaster (1966) found a terrace along the Atlantic shelf (from Newfoundland to South Carolina) at -145 m. This terrace probably corresponds to the first glacial maximum, which means a difference between the first and second glacial maxima of only 15 m (Morner, 1969a(Morner, , 1970d(Morner, , 1971b. A 15-m difference in sea level agrees well with the extent of the continental ice caps.…”

Atlantic continental shelf and slope of the United States: Sediment texture of the northeastern part

“…7) has more than one mode (a size interval with more sediment than either of the adjacent size classes) ; as such, these additional modes can be a useful indication of mixing from multiple sediment sources or through different agents of transport. Modes have been used by Curray (1960a, b) as a key to tracing different sediment contributions over the continental shelf on the Gulf Coast; Garrison and McMaster (1966) attempted the same type of analysis on the continental shelf off Rhode Island. Curray's analyses were made on a one-fourth-phi class interval, and modes were differentiated from cumulative grainsize curves.…”

“…Wigley (1961) also emphasized this lack of a gradation to finer grain size in deeper water away from Georges Bank. On the continental shelf south of New England, Garrison and McMaster (1966) pointed out the relict nature of the sediment (except for sandy areas near Nantucket Shoals). Hathaway, Schlee, Trumbull, and Hiilsemann (1965) and Emery (1968) also emphasized the relict nature of much sediment on the continental margin in terms of the processes of Pleistocene age that brought it there; postglacial reworking of bottom sediment in limited areas such as the shoals of Georges.…”

Summary report of the sediments, structural framework, petroleum potential, and environmental conditions of the United States middle and northern Continental Margin in area of proposed oil and gas lease sale no. 76

“…5-2). The fine sediment on the southern New England shelf previously was thought to be relict (Garrison and McMaster, 1966;Schlee, 1973), however, recent seismic-reflection profiles show that the fine sediment has accumulated since the last rise in sea level as it rests on Holocene terraces (Twichell and others, 1981). Carbon-14 ages and lead-210 profiles further suggest that this sediment has accumulated in recent time and may be actively accumulating at present (Bothner and others, in press).…”