Accession Number : AD0845252
Title : United States Naval Oceanographic Office Marine Geophysical Survey Program 1965-1967, North Atlantic Ocean, Norwegian Sea, and Mediterranean Sea Area 3, Volume 5, Geology and Geophysics.
Descriptive Note : Final rept.
Corporate Author : TEXAS INSTRUMENTS INC DALLAS SCIENCE SERVICES DIV
Report Date : 29 OCT 1968
Pagination or Media Count : 130
Abstract : Area 3 contains extensive abyssal-plain development on the ocean-basin floor seaward of the continental margins. The depth of the abyssal plains increases from 2550 fm on the Biscay abyssal plain at 48 degrees N to 2825 fm on the Iberia abyssal plain at 40 degrees N. The two plains are joined by Theta gap, a deep-sea channel system. Sediment thickness exceeds 1 km of predominantly terrigenous products. An area of abyssal hills extends west from the Iberia abyssal plain to the flank of the Mid-Atlantic ridge. The flank provinces of the Mid-Atlantic ridge are generally well-developed distinct features, mantled by 200 to 400 m of sediment except on the crestal provinces where sediment accumulation is much reduced. A seamount group oriented NW-SE effectively divides the lower step into two separate segments with contrasting topography and slope. King's trough, a NW-SE-trending trough and ridge complex, disrupts the middle step and part of the upper step in the central portion of the area. A portion of the Azores plateau is situated in the southwest corner of Area 3; a NW-SE-oriented positive feature, it lies normal to and disrupts the Mid-Atlantic ridge between 38 degrees N and 41 degrees N. The sediments on the Mid-Atlantic ridge are primarily fine-grained pelagics. That portion of the ridge below 2500 fm contains increased accumulations of red clay. (Author)
Descriptors : *MARINE GEOPHYSICS, *GEOLOGICAL SURVEYS, OCEAN BOTTOM TOPOGRAPHY, OCEAN BOTTOM SAMPLING, SEDIMENTATION, BATHYTHERMOGRAPH DATA, ATLANTIC OCEAN, NORWEGIAN SEA, MEDITERRANEAN SEA, MAPS.
Subject Categories : Physical and Dynamic Oceanography
Geology, Geochemistry and Mineralogy
Distribution Statement : APPROVED FOR PUBLIC RELEASE