| Registro completo |
| Provedor de dados: |
ArchiMer
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| País: |
France
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| Título: |
Preservation state of metastable magnesian calcite in periplatform sediments from the Caribbean Sea over the last million years
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| Autores: |
Sepulcre, Sophie
Tachikawa, Kazuyo
Vidal, Laurence
Thouveny, Nicolas
Bard, Edouard
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| Data: |
2009-11-21
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| Ano: |
2009
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| Palavras-chave: |
Mg-calcite preservation state
Mg/Ca in Mg-calcite
Caribbean Sea
Mid-Pleistocene
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| Resumo: |
Carbonate-rich periplatform sediments represent an active carbon reservoir containing metastable aragonite and magnesian calcite (Mg-calcite, > 4 mol % MgCO(3)). Since Mg-calcite is highly soluble, the preservation state of this mineral provides information on past carbonate systems at water depths shallower than the lysocline. The mineralogy and geochemistry of the carbonate-rich fine fraction (< 63 mu m) was determined for the last 940 ka in a sediment core collected from the Walton Basin (Northern Caribbean Sea, 846 m water depth). Mg/Ca ratios for Mg-calcite showed clear glacial-interglacial cycles with high values (12 mol % MgCO(3)) during interglacials. Glacial Mg/Ca ratios were approximately 8 mol % MgCO(3) for the period from 940 ka to 400 ka, and approximately 10 mol % MgCO(3) for the last 400 ka. The Mg/Ca shift is concomitant with a preferential loss of Mg-calcite relative to aragonite. The preservation state of Mg-calcite revealed that the bottom water mass of the studied site was slightly more corrosive for the earlier period, possibly relating to a composition change in intermediate water and/or to the ventilation rate in the Atlantic Ocean.
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| Tipo: |
Text
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| Idioma: |
Inglês
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| Identificador: |
https://archimer.ifremer.fr/doc/00218/32908/31417.pdf
DOI:10.1029/2009GC002779
https://archimer.ifremer.fr/doc/00218/32908/
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| Editor: |
Amer Geophysical Union
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| Formato: |
application/pdf
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| Fonte: |
Geochemistry Geophysics Geosystems (1525-2027) (Amer Geophysical Union), 2009-11-21 , Vol. 10 , N. 11 , P. 1-15
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| Direitos: |
Copyright 2009 by the American Geophysical Union
info:eu-repo/semantics/openAccess
restricted use
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