Biblioteca de la Universidad Complutense de Madrid

Datos geofísicos y evolución sedimentaria de la Depresión de la Janda (Cádiz)

Impacto



Luque, Luis de y Silva Barroso, Pablo Gabriel y Zazo Cardeña, Caridad y Recio, J.M. y Carrasco, P. y Goy Goy, José Luis y Dueñas, M.I. y Lario, Javier y Dabrio, Cristino J. y González Hernández, F.M. y Poza, L. (2001) Datos geofísicos y evolución sedimentaria de la Depresión de la Janda (Cádiz). Geogaceta, 29 . pp. 69-72. ISSN 0213-683X

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Resumen

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 the
thickness of Quaternary sediments infilling the graben. Nevertheless, the results are significantly distorted
by a saline aquifer that occupies most of the sedimentary filling. In any case it is possible to identify an
assymetric 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 here
called A, B 1, B2, characterised by resistivity differences. The shallow 4-6 m thick Unit A consists of a thin
lacustrine and alluvial e/ay and silts of Holocene age easily recognized in seismic refraction profiles and
drill cores. Unit B can be separated in two subunits; Both are saturated in brackish or saline waters; B1 is
a 20-40 m thick unit that thins northward and correspond to the Plio-Pleistocene, B2 is a slightly more
resistive unit that extends from this depth to 352 m and corresponds to deeply weathered mio-pliocene
sandstones. The upper part of Sub-unit B1 correspond to estuarine sands recorded in a previous core
which deposition finishes at ca. 3810 cal BP. A sharp normal fault limits the southern part of La Janda
assymetric graben.


Tipo de documento:Artículo
Palabras clave:La Janda Graben, Geophysical data, Quaternary sedimentation
Materias:Ciencias > Geología > Geología estratigráfica
Código ID:10942
Depositado:30 Jun 2010 07:58
Última Modificación:30 Abr 2014 09:50

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