%0 Journal Article
%A Luque, Luis de
%A Silva Barroso, Pablo Gabriel
%A Zazo Cardeña, Caridad
%A Recio, J.M.
%A Carrasco, P.
%A Goy Goy, José Luis
%A Dueñas, M.I.
%A Lario, Javier
%A Dabrio González, Cristino José
%A González Hernández, F.M.
%A Poza, L.
%T Datos geofísicos y evolución sedimentaria de la Depresión de laJanda (Cádiz)
%D 2001
%@ 0213-683X
%U https://hdl.handle.net/20.500.14352/56872
%X La Janda lake is located into a tectonic graben filled by Pleistocene and Holocene f1uvio-marine sediments.Geophysical survey consisting on Electric-Iogs and seismic refraction profiles aimed to determining thethickness of Quaternary sediments infilling the graben. Nevertheless, the results are significantly distortedby a saline aquifer that occupies most of the sedimentary filling. In any case it is possible to identify anassymetric subsident area reaching up to 300 m depth, characterised by very low apparent resistivities(1.5-2.4 W/m). This thick geoelectrical unit can be preliminary subdivided into 3 different subunits herecalled A, B 1, B2, characterised by resistivity differences. The shallow 4-6 m thick Unit A consists of a thinlacustrine and alluvial e/ay and silts of Holocene age easily recognized in seismic refraction profiles anddrill cores. Unit B can be separated in two subunits; Both are saturated in brackish or saline waters; B1 isa 20-40 m thick unit that thins northward and correspond to the Plio-Pleistocene, B2 is a slightly moreresistive unit that extends from this depth to 352 m and corresponds to deeply weathered mio-pliocenesandstones. The upper part of Sub-unit B1 correspond to estuarine sands recorded in a previous corewhich deposition finishes at ca. 3810 cal BP. A sharp normal fault limits the southern part of La Jandaassymetric graben.
%~