Sources and transport of suspended calcites in Pacific Deep Water

Autor: R. Chesselet, C. E. Lambere, Jean-Claude Brun-Cottan, R. Auger
Přispěvatelé: Institut de Biogéochimie Marine, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre des Faibles Radioactivités, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 1991
Předmět:
Zdroj: Journal of marine research
Journal of marine research, 1991, 49 (3), pp.543-564. ⟨10.1357/002224091784995837⟩
ISSN: 1543-9542
0022-2402
DOI: 10.1357/002224091784995837
Popis: International audience; Significantly large concentrations of suspended matter, especially calcites, are found at some locations in the Deep Pacific, particularly at the depth of the Pacific Benthic Thermocline. These particle-rich layers cannot be explained by simple classical settling processes nor by resuspension of the underlying sediment. A theoretical approach based on these data, on the hydrodynamic characteristics of the regional circulation and on some known physical and chemical parameters, leads us to postulate two possible mechanisms: the settling of large particles from surface waters and their preferential disaggregation at some specific depth, particularly at the Pacific Benthic Thermocline depth; or alternatively, the resuspension atthose depths of old calcareous sediments from the flanks of East Pacific Rise associated with a horizontal advective diffusive transport mechanism. New chemical and electron-microscopeanalyses of GEOSECS samples give rise to the conclusion that the resuspension mechanism is the most probable. A simple model based on this mechanism, using our calcite concentrationsat the PBT depth implies that the calcium carbonate flux arising from this source ranges between 5 x 10$^$6 and 5 x 10$^8$ tons per year. The erosion intensity and the quantity of calciumcarbonate contained by the rises or the seamounts, must be large enough to maintain this flux. Those two constraints have been successfully tested.
Databáze: OpenAIRE
Externí odkaz: