Inner shelf paleoenvironmental evolution as a function of land-ocean interactions in the vicinity of the Guadiana River, SW Iberia

Mendes, I., Rosa, F., Dias, J. A., Schönfeld, Joachim, Ferreira, Ó. and Pinheiro, J. (2010) Inner shelf paleoenvironmental evolution as a function of land-ocean interactions in the vicinity of the Guadiana River, SW Iberia Quaternary International, 221 (1/2). pp. 58-67. DOI 10.1016/j.quaint.2009.10.037.

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Abstract

This study investigates the land–ocean interactions along the northern margin of the Gulf of Cadiz in the vicinity of the Guadiana River. Benthic foraminifera and sedimentological characteristics were analysed in a sedimentary sequence spanning ca. 5000 years (core 8, 22 m water depth) retrieved from the inner shelf prodeltaic wedge. The analyses were integrated in a temporal framework based on accelerated mass spectrometry radiocarbon dating. Paleoenvironmental changes and sediment transfer mechanisms from the continent to the shelf were investigated and related to climatic oscillations and anthropogenic impact in the region.

The results allowed the identification of two main periods of deposition. The first period, from ca. 5150 cal. BP (core base) to 1500–1200 cal. BP, is characterised by a mix of fine and coarse sediments, relatively constant percentages of terrigenous and bioclasts, and benthic foraminifera species characteristic of coastal environments. These features indicate an environment strongly influenced by discharge from the Guadiana River. The second period, from ca. 1500–1200 cal. BP to ca. 200 cal. BP (core top), is characterised by silt-clay fraction dominated sediments, an increase in terrigenous sediment towards the top, and benthic foraminifera species characteristic of environments with low levels of energy. An increase in the level of human occupation associated with changes in climate led to widespread erosion and soil loss to the continental shelf during this period, with possible silting up of the Guadiana eastern distributary, allowing the transport of high amounts of sediment to the shelf by the western distributary that led to the enhancement of fine sedimentation and the formation of the prodeltaic wedge in the area of the studied core.

Document Type: Article
Keywords: Paleoceanography; Benthic foraminifera, continental shelf, sediments, Guadiana River, Holocene
Research affiliation: OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
OceanRep > The Future Ocean - Cluster of Excellence
Refereed: Yes
DOI etc.: 10.1016/j.quaint.2009.10.037
ISSN: 1040-6182
Projects: Future Ocean
Date Deposited: 25 Aug 2010 13:53
Last Modified: 19 Sep 2016 13:05
URI: http://eprints.uni-kiel.de/id/eprint/8820

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