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.

• Other Authors: TEXAS INSTRUMENTS INC DALLAS SCIENCE SERVICES DIV
• Format: Text
• Language: English
• Published: 1968
• Subjects: Physical and Dynamic Oceanography; Geology; Geochemistry and Mineralogy; *MARINE GEOPHYSICS; *GEOLOGICAL SURVEYS; OCEAN BOTTOM TOPOGRAPHY; OCEAN BOTTOM SAMPLING; SEDIMENTATION; BATHYTHERMOGRAPH DATA; ATLANTIC OCEAN; NORWEGIAN SEA; MEDITERRANEAN SEA; MAPS; ABYSSAL HILLS; ABYSSAL PLAINS; SEAMOUNTS; Mid-Atlantic Ridge; Norwegian Sea; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/AD0845252; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=AD0845252

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)