Abyssal Geomorphology of a Depositional Environment at the Exit of the Samoan Passage.
Abstract
To the north of the sill of the narrow Samoan Passage (8 degrees S, 168 degrees 30'W) 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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1974
- Accession Number
- ADA007330
Entities
People
- Peter F. Lonsdale
Organizations
- Scripps Institution of Oceanography