Studies of Deep Sea Erosion Using Deep-Towed Instrumentation
Abstract
Detailed geological and geophysical studies were conducted in a region of the equatorial Pacific (near 07 deg 40'N, 134 deg 00'W), using the deep-towed instrumentation of the Marine Physical Laboratory. Sediment cores and near-bottom reflection profiles show a sharp angular unconformity a few cm beneath the sea floor, which separates a thin upper layer of Holocene sediment from a chalk of Tertiary age. This unconformity is interpreted as a Pleistocene erosion surface which truncates sediments ranging in age from Upper Eocene to Middle Miocene. Bottom currents have evidently caused the erosion and redistribution of sediment tens to hundreds of meters in thickness. Much of the eroded material has been redeposited into a large (15 km x 25 km) topographic basin containing sediments which are considerably thicker than those in the surrounding region. Prominent channels feed into the basin from the areas where erosion has taken place. Significant ocean floor erosion in the central Pacific did not begin until the late Tertiary, and was perhaps restricted to the glacial stages of the Pleistocene when bottom currents may have been considerably stronger than those present today.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1971
- Accession Number
- AD0740813
Entities
People
- David A. Johnson
Organizations
- Scripps Institution of Oceanography