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Peter A. Rona

Publications and source records attributed to Peter A. Rona.

2 recordsLinked to original sources

Sea floor topography and backscatter intensity of the Hudson Canyon region offshore of New York and New Jersey

These maps show the sea floor topography and backscatter intensity of the Hudson Canyon region on the continental slope and rise offshore of New Jersey and New York (fig. 1 and fig. 2). Sheet 1 shows sea floor topography as shaded relief. Sheet 2 shows sea floor topography as shaded relief with backscatter intensity superimposed in color. Both sheets are at a scale of 1:300,000 and also show smoothed topographic contours at selected intervals. The maps are based on new multibeam echo-sounder data collected on an 18-day cruise carried out aboard the National Oceanic and Atmospheric Administration (NOAA) Ship Ronald H. Brown during August and September 2002. Additional multibeam data of the Hudson Canyon collected by the Woods Hole Oceanographic Institution (WHOI), on the continental shelf collected by the STRATAFORM project (Goff and others, 1999), and a survey of the Hudson Shelf Valley (Butman and others, 2003), and a compilation of bathymetric data from the National Geophysical Data Center (NGDC) Coastal Relief Model provide coverage of areas surrounding Hudson Canyon (fig. 2). Interpretations of the surficial geology also utilize widely spaced 3.5- and 10-kiloHertz (kHz) high-resolution seismic profiles collected by the U.S. Geological Survey (fig.2).

New Jersey, New York

Major off-axis hydrothermal activity on the northern Gorda Ridge

The first hydrothermal field on the northern Gorda Ridge, the Sea Cliff hydrothermal field, was discovered and geologic controls of hydrothermal activity in the rift valley were investigated on a dive series using the DSV Sea Cliff . The Sea Cliff hydrothermal field was discovered where predicted at the intersection of axis-oblique and axis-parallel faults at the south end of a linear ridge at mid-depth (2700 m) on the east wall. Preliminary mapping and sampling of the field reveal: a setting nested on nearly sediment-free fault blocks 300 m above the rift valley floor 2.6 km from the axis; a spectrum of venting types from seeps to black smokers; high conductive heat flow estimated to be equivalent to the convective flux of multiple black smokers through areas of the sea floor sealed by a caprock of elastic breccia primarily derived from basalt with siliceous cement and barite pore fillings; and a vent biota with Juan de Fuca Ridge affinites. These findings demonstrate the importance of off-axis hydrothermal activity and the role of the intersection of tectonic lineations in controlling hydrothermal sites at sea-floor spreading centers.

Gorda Ridge