Response of the Rhone deltaic margin to loading and subsidence during the last climatic cycle

Type Article
Date 2008-10
Language English
Author(s) Jouet Gwenael1, 2, Hutton E3, Syvitski J3, Berne Serge1
Affiliation(s) 1 : IFREMER, Lab Environm Sedimentaires, Dept Geosci Marines, French Res Inst Exploitat Sea, F-29280 Plouzane, France.
2 : Univ Bretagne Occidentale, Lab CNRS UMR Domaines Ocean 6538, IUEM, F-29280 Plouzane, France.
3 : Univ Colorado, Environm Computat & Imaging Facil, INSTAAR, Boulder, CO 80309 USA.
Source Computers & Geosciences (0098-3004) (Elsevier), 2008-10 , Vol. 34 , N. 10 , P. 1338-1357
DOI 10.1016/j.cageo.2008.02.003
WOS© Times Cited 12
Keyword(s) Gulf of Lions, Continental shelf, Sedflux, Stratigraphic simulations, Isostasy, Subsidence
Abstract Passive continental margin subsidence is initiated by the synrift mechanical stretching of the lithospheric upper brittle layer and continues during the postrift phase; the thermal cooling and contraction of the upwelled asthenosphere forces the margin to subside in addition to the overloads from sea water and sediments. Therefore, the total subsidence in stretched basins includes fault-controlled initial sinking, thermal subsidence and flexural isostatic compensations. Decoupling and estimating the different components of this subsidence from stratigraphic analysis and restricted geophysical and sedimentological databases remains problematic. In particular, backstripping the sediment layers requires a well-constrained geological framework. A method is proposed here to investigate the subsidence history of a margin based on forward stratigraphic modelling. Using the Sedflux model, several experiments are done using generally agreed upon assumptions on the parameters describing lithospheric theology and isostatic behaviour of a margin. The stratigraphic modelling of the Rhone deltaic margin during the last climatic cycle (125 kyr) provides an assessment of these parameter estimates and their influence on geohistory (tectonic/thermal subsidence and sediment loading). The model results confirm the important impact of water loading on vertical deflection along the platform between glacial low sea-level and interglacial high sea-level. Based on Gulf of Lions (NW Mediterranean) observations, a conceptual method that uses the stratigraphic simulations is produced in order to evaluate the different components of the total subsidence of a margin, and, in particular, the relative impact of tectonic subsidence and sediment load.
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