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W. W. Danforth

Publications and source records attributed to W. W. Danforth.

44 records · Page 3Linked to original sources
USGS1997

Initial results of high-resolution sea-floor mapping offshore of the New York - New Jersey metropolitan area using sidescan sonar

High-resolution seismic, sidescan-sonar, multibeam bathymetry, and sediment sampling techniques were used to map the surficial geology and shallow subbottom stratigraphy of a segment of the inner shelf and nearshore region of New York-New Jersey metropolitan area. Preliminary analyses of these data provide a sedimentologic framework for addressing a wide range of science and management issues. Principal features identified include: 1) a series of sharply defined, rippled scour depressions in the nearshore areas of Long Island and New Jersey that are thought to be an erosional pattern indicative of storm-induced cross-shelf sediment-transport processes from the shoreface; 2) outcropping Upper Cretaceous to early Tertiary coastal plain strata and associated gravelly lag deposits; 3 ) morphologic and chemical indications of anthropogenic waste disposal and redistribution; 4) extensive deposits of medium- to fine-grained sand northeast and east of the Hudson Shelf Valley; 5) acoustic backscatter patterns on the sidescan imagery and sediment bedforms that indicate a general south-southwest sediment transport direction toward the Hudson Shelf Valley; and 6) the Hudson Shelf Valley is a depositional site for silty sediment and acts as a conduit for cross-shelf pollutant transport.

Northeastern Geology and Environmental Sciences↗
USGS1991

A giant submarine slope failure on the northern insular slope of Puerto Rico

A large amphitheater-shaped scarp, approximately 55 km across, was imaged on the northern insular slope of Puerto Rico using long-range sidescan sonar and bathymetric data. This scarp results from the removal of more than 1500 km 3 of Tertiary strata. A review of seismic-reflection profiles, stratigraphic data, and subsidence models of the northern insular margin of Puerto Rico were used to infer that large-scale slope failure was induced by the tectonic oversteepening of the insular slope and was responsible for the formation of the scarp. The oversteepening probably was caused by the most recent episode of convergence of the Caribbean and North American plates, which began between approximately 4 and 2.5 m.y. ago. The Tertiary strata have been tilted approximately 4.5° to the north in the last 4 m.y.

Marine Geology↗