The abundance and distribution of biogenic, terrigenous and
volcanic particles in the Panama Basin are markedly dependent on
bottom topography and dissolution of calcite in the deeper parts of the
basin. Of the coarse fraction (>62μ), foraminiferal tests and acidic
volcanic glass shards are concentrated on the Cocos and Carnegie
Ridges as lag deposits. Foraminiferal fragments are found on these
ridge flanks and on the Malpelo Ridge due to reworking by bottom
currents accentuated by dissolution of calcite with increasing depth.
The finest calcite, probably coccoliths with fine foraminiferal fragments, together with the hydrodynamically light radiolarian skeletons
are concentrated by bottom currents in the basin adjacent to the
ridges.
The foraminiferal calcite compensation depth in the basin is
3400 m. This relatively shallow depth probably reflects the high
surface water productivity over the basin, although the pattern of
productivity is not reflected in the pattern of biogenic sediments.
Acidic volcanic glass appears to have been carried into the
basin from Costa Rica, Colombia and Ecuador by easterly winds at
altitudes of 1500 to 6000 m. Basaltic shards from the Galapagos
Islands have been dispersed only over short distances to the west.
Terrigenous sand-sized material is found on the edge of the continental
shelf, where associated glauconite points to a relict origin, and
along the northern Cocos Ridge, where contour currents may act as
the dispersal mechanism. / Graduation date: 1973
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/28380 |
| Date | 27 October 1972 |
| Creators | Kowsmann, Renato O. |
| Contributors | Heath, G. Ross |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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