%0 Journal Article
%A Zazo Cardeña, Caridad
%A Mercier, Norbert
%A Lario, Javier
%A Roquero, Elvira
%A Goy Goy, José Luis
%A Silva Barroso, Pablo Gabriel
%A Cabero del Río, Ana
%A Borja, Francisco
%A Dabrio González, Cristino José
%A Bardají Azcárate, Teresa
%A Soler Javaloyes, Vicente
%A García Blázquez, Ana
%A Luque, Luis de
%T Palaeoenvironmental evolution of the Barbate–Trafalgar coast (Cadiz) during thelast ~ 140 ka: Climate, sea-level interactions and tectonics
%D 2008
%@ 0169-555X
%U https://hdl.handle.net/20.500.14352/49383
%X Coastal response to tectonic activity and eustatic-climate interactions during the Late Pleistocene andHolocene has been analyzed along the Barbate–Trafalgar shoreline. The study area consists of an upliftedplatform (La Breña, ~140 m) bounded by two major NW–SE faults that have created two subsiding areas:Meca in the west and Barbate in the east. The areas of subsidence have favoured the accumulation of a thickmorphosedimentary sequence consisting of (in ascending stratigraphic order) beach, alluvial, and aeoliandeposits, which repeatedly underwent soil-forming processes. This study outlines the palaeogeographicalevolution of the area over the last ~140 ka, as deduced from geomorphological mapping associated with arange of laboratory analyses (mineralogical, geochemical, magnetic susceptibility, and soil micromorphologyanalyses), optically stimulated luminescence (OSL dating), and existing U–Th dating. Special attention hasbeen paid to the alluvial unit, made up of vertically stacked sandy sheet-flood deposits with interbedded redpaleosols. OSL ages suggest that sediment supply to the alluvial/coastal environments took place mainly atthe end of the two most recent glacial periods (Oxygen Isotopic Stage [OIS] 6 and OIS 3/OIS 2) and during thelast interglacial period (end of OIS 5). This means that although alluvial sedimentation took place at times ofrelatively high sea level, these were not times of highstand because very high sea levels (like the present)allow marine erosion of the distal part of the fans (fan toes), cutting cliffed coasts.The repeated occurrence of paleosols in the alluvial sequence seems to indicate a recurrence ofenvironmental changes that modified the feedback relationships between the catchment and the coastalareas. These changes are recorded in repeated oscillations of soil parameters, and are revealed from theresults of geochemical and environmental magnetism analyses. We associate repeated pedogenesis andalluvial sedimentation with the glacial/interglacial global climatic changes due to an oscillating humidity/aridity ratio rather than with cyclicity in thermal regime.
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