Publications

No abstract available.

Undersea discharge of ground water during periods of lower sea level may have eroded valleys on part of the lower continental slope, offshore New Jersey. Steep-headed basins, cliffed and terraced walls, and irregular courses of these valleys may have been produced by sapping of exposed near-horizontal Tertiary strata. Joints in Eocene calcareous rocks would have localized ground-water...

The continental slope off the northeastern United States is a relatively steep, morphologically complex surface which shows abundant evidence of submarine slides and related processes. Because this area may be developed by the petroleum industry, questions arise concerning the potential for further slope failures or unacceptable deformations and the conditions necessary to cause such...

From July 1981, when drilling began on Georges Bank, to May 1982, the concentration of barium, a major element in drilling mud, has increased by a factor of 3.5 in bulk sediments 200 m from the drill site in block 410 and by a factor of 2.3 at the drill site in block 312. The postdrilling barium concentrations are within the range of predriiling concentrations measured at other locations...

Rock magnetic properties, opaque mineralogy, and degree of metamorphism were determined for 101 unoriented samples from the North Arm and Blow-Me-Down massifs of the Bay of Islands ophiolite complex, Newfoundland. The weathered and metamorphosed extrusive basalt samples have a weak, secondary magnetization arising from oxidation and exsolution of ilmenite of unknown origin. The initial

Ferromanganese crusts on raised areas of the ocean floor have joined abyssal manganese nodules and hydrothermal sulfides as potential marine resources. Significant volumes of cobalt-rich (about 1% Co) crusts have been identified to date within the US Exclusive Economic Zone (EEZ) in the Central Pacific: in the NW Hawaiian Ridge and Seamount region and in the seamounts in the Johnston...

A new database for ferromanganese crusts from the world oceans is being compiled by the U.S. Geological Survey. Crusts differ from abyssal nodules by forming principally on steeper, raised areas or current-swept plateaus in the oceans. Some crusts contain relatively large concentrations of cobalt (1.0%) in areas within national territorial jurisdictions.

No abstract available.

Knowledge of the physical oceanography of continental shelves has increased tremendously in recent years, primarily as a result of new current and hydrographic measurements made in locations where no comparable measurements existed previously. In general, observations from geographically distinct continental shelves have shown that the nature of the flow may vary considerably from region...

The geology of the part of Lydonia Canyon shoreward of the continental shelf edge on the southern side of Georges Bank was mapped using high-resolution seismic-reflection and side-scan sonar techniques and surface sediment grab samples. The head of the canyon incises Pleistocene deltaic deposits and Miocene shallow marine strata. Medium sand containing some coarse sand and gravel covers...

A submerged delta of the Merrimack River, located offshore between Cape Ann, Massachusetts, and the New Hampshire border, indicates a postglacial low relative see-level stand of about -47 m. The low stand is inferred to date to 10,500 yr B.P., but a lack of age control makes this assignment uncertain. A curve based on a late Wisconsinan, high relative sea-level stand of +32m at 13,000 yr...

A major pre-Wisconsinan glacial event is the only possible source of the lower till on Nantucket Island, Massachusetts. The till occurs near the late Wisconsinan drift border and below fossiliferous marine beds of oxygen-isotope stage 5 (Sangamonian) age. It is considered to be Illinoian in age, but the evidence is tenuous. The till is correlated with the lower till of New England, and...