Accession Number : AD0713165

Title :   NEAR-BOTTOM STUDIES OF THE EAST PACIFIC RISE CREST AND TECTONICS OF THE MOUTH OF THE GULF OF CALIFORNIA,

Corporate Author : SCRIPPS INSTITUTION OF OCEANOGRAPHY SAN DIEGO CALIF MARINE PHYSICAL LAB

Personal Author(s) : Larson,Roger Lee

Report Date : 01 JUL 1970

Pagination or Media Count : 180

Abstract : Bathymetric and magnetic measurements have been used to delineate the boundary between the North American and Pacific Plates in the vicinity of the mouth of the Gulf of California and indicate a spreading rate of 6 cm/yr. Magnetic anomalies, fracture zones and earthquake mechanisms indicate the validity of the rigid plate assumption for the interactions between the Pacific, American and Cocos plates. A survey with a near-bottom instrument over the East Pacific Rise crest shows lineated abyssal hills with no sediment cover at the rise crest itself. Magnetic field measurements made near the ocean floor show to a certain extent the history of the earth's magnetic field over the last 1.2 million years and show a reversal transition time of 1000 years and intensity fluctuations with periods ranging between 18000 and 50000 years. (Author)

Descriptors :   (*OCEAN BOTTOM TOPOGRAPHY, *PACIFIC OCEAN), BATHYTHERMOGRAPH DATA, MAGNETIC ANOMALY DETECTION, EARTHQUAKES, HYDROGRAPHIC SURVEYING, INTERACTIONS, MARINE GEOPHYSICS, SONAR, DETECTION

Subject Categories : Physical and Dynamic Oceanography
      Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE