Subseafloor stratigraphic profiling and soil classification from piezocone tests: A case study in the Gulf of Lion (NW Mediterranean Sea)
|Author(s)||Lafuerza S.1, Frigola J.1, Canals M.1, Jouet Gwenael2, Bassetti Maria-Angela3, Sultan Nabil2, Berne Serge3|
|Affiliation(s)||1 : Univ Barcelona, GRC Geociencies Marines, Dept Estratig Paleontol & Geociencies Marines, E-08028 Barcelona, Spain.
2 : Inst Francais Rech Exploitat Mer, F-29280 Plouzane, France.
3 : Univ Perpignan Via Domitia, IMAGES, F-66860 Perpignan, France.
|Source||Geochemistry Geophysics Geosystems (1525-2027) (American Geophysical Union), 2008-12 , Vol. 9 , N. 12 , P. 1-13|
|WOS© Times Cited||4|
|Keyword(s)||Gulf of Lion, Soil classification, Stratigraphy, Piezocone|
|Abstract||We show the results provided by piezocone tests in determining the stratigraphic profile and the soil classification of two drilling sites in the outer shelf and the upper slope of the Gulf of Lion, PRGL2 and PRGL1, respectively. Correlations with grain-size data indicate that sleeve friction can be used for profiling fine-grained sediments (site PRGL1), whereas cone tip resistance is the most adequate for sequences made of alternations of coarse- and fine-grained intervals (site PRGL2). Normalized cone resistance and friction ratio proved to be also appropriate for soil stratigraphy as it depicts trends in the coarse fraction of the tested soil. Silts and clays present in similar proportions at site PRGL1 responded to piezocone testing as pure clays usually do. Consequently, classical soil classification methods resulted in erroneous interpretation of these sediments as clays, whereas classification of the heterogeneous deposits at PRGL2 was consistent with the grain size. When tied to a high-resolution seismic reflection profile, the stratigraphy interpreted from the piezocone profile matches with the main seismic sequences and discontinuities defined from seismic stratigraphy analysis. Graded bedding also matches with cone tip resistance and sleeve friction data.|