Magnetic charachterization of surface sediments in the South Atlantic
Autoria(s):
Schmidt, Andrea
Cobertura
MEDIAN LATITUDE: -17.873506 * MEDIAN LONGITUDE: -18.815800 * SOUTH-BOUND LATITUDE: -39.290000 * WEST-BOUND LONGITUDE: -59.388333 * NORTH-BOUND LATITUDE: 12.718333 * EAST-BOUND LONGITUDE: 17.861667 * DATE/TIME START: 1988-02-20T00:00:00 * DATE/TIME END: 1996-04-14T00:00:00 * MINIMUM ELEVATION: -5684.0 m * MAXIMUM ELEVATION: -237.0 m
Data(s)
27/05/1999
Resumo
Surface sediment samples representative for the tropical and subtropical South Atlantic (15°N to 40°S) were investigated by isothermal magnetic methods to delineate magnetic mineral distribution patterns and to identify their predominant Holocene climatic and oceanographic controls. Individual parameters reveal distinct, yet frequently overlapping, regional sedimentation characteristics. A probabilistic ('fuzzy c-means') cluster analysis was applied to five concentration independent magnetic properties assessing magnetite to hematite ratios and diagnostic of bulk and fine-particle magnetite grain size and coercivity spectra. The resultant 10 cluster structures establish an oceanwide magnetic sediment classification scheme tracing the major terrigenous eolian and fluvial fluxes, authigenic biogenic magnetite accumulation in high-productivity areas, transport by ocean current systems, and effects of bottom water velocity on depositional regimes. Distinct dissimilarities in magnetic mineral inventories between the eastern and western basins of the South Atlantic reflect prominent contrasts of both oceanic and continental influences.
Schmidt, Andrea (2001): Magnetic Mineral Fluxes in the Quaternary South Atlantic: Implications for the Paleoenvironment. Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen, 175, 97 pp, urn:nbn:de:gbv:46-ep000103001
Direitos
CC-BY: Creative Commons Attribution 3.0 Unported
Access constraints: unrestricted
Fonte
Supplement to: Schmidt, Andrea; von Dobeneck, Tilo; Bleil, Ulrich (1999): Magnetic characterization of Holocene sedimentation in the South Atlantic. Paleoceanography, 14(4), 465-481, doi:10.1029/1999PA900020
