Accession Number:

ADA007330

Title:

Abyssal Geomorphology of a Depositional Environment at the Exit of the Samoan Passage.

Descriptive Note:

Summary rept.,

Corporate Author:

SCRIPPS INSTITUTION OF OCEANOGRAPHY SAN DIEGO CALIF MARINE PHYSICAL LAB

Personal Author(s):

Report Date:

1974-11-01

Pagination or Media Count:

99.0

Abstract:

To the north of the sill of the narrow Samoan Passage 8 degrees S, 168 degrees 30W the upper transparent layer of the Central Basin of the Pacific occurs in isolated patched molded by rather steady bottom currents. An intensive study of a part of this region, at a depth of 5.5 to 5.8km described the nature and distribution of the current-transported sediments and its bedforms, and measured the present current flow. The sediments are mainly brown clays, frequently rich in reworked radiolaria, but include calcareous material, sometimes laminated and cross-bedded, that has been reworked from shallower sites. The most striking bedforms are branching longitudinal furrows, with depths of about 1m and wavelengths of about 50m, that are eroded into reworked nannofossil ooze. The surface of adjacent brown clay is covered with stripes on side-looking somar records thought to be caused by lines of manganese nodules. Flow through the Samoan Passage began near the Paleogene-Neogene boundary, and was probably fastest in the late Pliocene and Pleistocene times.

Subject Categories:

  • Physical and Dynamic Oceanography
  • Geology, Geochemistry and Mineralogy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE