Quaternary stratigraphic model and sedimentary processes along two carbonate slopes in the Bahamas (leeward and windward)
This study proposes a reconstruction of the quaternary sedimentary history of two Bahamian slopes (leeward and windward). This work is based on the stratigraphicand sedimentary analysis of 34 marine cores recovered mainly from the CARAMBAR oceanographic cruse (2010). A high-resolution stratigraphic...
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Other Authors: | , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
Published: |
HAL CCSD
2016
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Subjects: | |
Online Access: | https://tel.archives-ouvertes.fr/tel-01355583 https://tel.archives-ouvertes.fr/tel-01355583/document https://tel.archives-ouvertes.fr/tel-01355583/file/CHABAUD_LUDIVINE_2016.pdf |
Summary: | This study proposes a reconstruction of the quaternary sedimentary history of two Bahamian slopes (leeward and windward). This work is based on the stratigraphicand sedimentary analysis of 34 marine cores recovered mainly from the CARAMBAR oceanographic cruse (2010). A high-resolution stratigraphic study was conducted by coupling several tools including ecostratigraphy based on planktonic foraminifera assemblages, which allowed dating all sedimentary sequences despite early diagenesis processes. The sedimentary analysis of the marine cores proposes a new classification for carbonate sediment. It characterizes the dominant particle distributions at the time of deposition and allows for discriminating the fine sediments and for determining the depositional processes such as off-bank transport, contouritic or gravity deposits, and slightly altered sediment. Off-bank transport is the mainprocess responsible for high-accumulation of platform carbonate ooze (aragonite needles and silt) on the Bahamian slopes. It predominates during major flooding of the platform, so during the last 4 ka cal BP, the MIS 5e and at the on set of the MIS11. Intra-slope erosion, bottom currents, and early marine diagenesis processes have also been highlighted. The leeward slope is characterized by a high accumulation of wackestone sediment where as the windward slope preserved its Pliocene morphology with local quaternary sediment accumulation (wackestone to packstone). Cette étude présente une reconstruction du fonctionnement sédimentaire au Quaternaire de deux pentes carbonatées des Bahamas (leeward et windward). Elle est basée sur les analyses stratigraphique et sédimentaire de 34 carottes principalement collectées lors de la mission CARAMBAR (2010). Une étude stratigraphique à haute résolution a été développée à partir de plusieurs outils stratigraphiques, dont l’écostratigraphie basée sur les assemblages de foraminifères planctoniques qui a permis de dater l’ensemble des séquences sédimentaires en s’affranchissant des problèmes liés ... |
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