Overpressure within upper continental slope sediments from CPTU data, Gulf of Lion, NW Mediterranean Sea
|Author(s)||Lafuerza S.1, Sultan Nabil2, Canals M.1, Frigola J.1, Berne Serge3, Jouet Gwenael2, Galavazi M.4, Sierro F. J.5|
|Affiliation(s)||1 : Univ Barcelona, GRC Geociencies Marines, Dept Estratig Paleontol & Geociencies Marines, E-08028 Barcelona, Spain.
2 : IFREMER, F-29280 Plouzane, France.
3 : Univ Perpignan, F-66860 Perpignan, France.
4 : Fugro Engineers BV, NL-2264 SG Leidschendam, Netherlands.
5 : Univ Salamanca, Dept Geol, E-37008 Salamanca, Spain.
|Source||International Journal of Earth Sciences (1437-3254) (Springer), 2009-06 , Vol. 98 , N. 4 , P. 751-768|
|WOS© Times Cited||19|
|Keyword(s)||Gulf of Lion, Continental slope, Overpressure, Preconsolidation pressure, Stress history|
|Abstract||Data from in situ piezocone tests (CPTU) and laboratory analyses are utilized for the interpretation of the stress history of Quaternary sedimentary sequences in the upper continental slope of the Gulf of Lion, northwestern Mediterranean Sea. A CPTU based preconsolidation pressure profile referenced to the current effective stress indicates that the deposit is underconsolidated from 12 meters below the seafloor (mbsf) down to at least 150 mbsf. Excess pore pressure below 12 mbsf is further supported by results from oedometer and dissipation tests. Subseafloor pockmarks and indications of free gas in seismic reflection profiles reveal four main overpressure sources (SI-SIV) with overpressure ratios > 0.3 at subseafloor depths coinciding with levels where the dominantly silty-clayey sediment contains increased proportions of sand. We relate the excess pore pressure related to free gas due to gas exsolution processes and sea level variations driven by Pleistocene sea level changes.|