Retracing the Quaternary history of sea-level changes in the Spanish Mediterranean–Atlantic coasts: Geomorphological and sedimentological approach

Abstract

This study analyses coastal geomorphic responses to the various sea-level changes that occurred throughout the Quaternary period in the Mediterranean and Atlantic coasts of Spain. Particular emphasis is paid to the geomorphic and stratigraphic record of the changes in amplitude, duration and frequency associated with the major gradual climate changes observed in marine cores and ice oxygen-isotope records during the Early and Middle Pleistocene (ca. 2.6Myr; ca. ~1.4–0.8Myr; ca. ~0.4–0.2Myr) and also with the rapid and abrupt Late Pleistocene and Holocene climate changes. With this aim, the best preserved and most complete sedimentary sequences known in the Spanish Mediterranean and Atlantic coasts covering diverse geodynamic and climatic contexts were selected and analyses. This study is mainly based on field investigation of geomorphic, sedimentologic and stratigraphic features of mapped morphosedimentary units, combined with reliable chronological data. The analyses include the interpretation of sedimentary environments, the 3-D reconstruction of facies and morphosedimentary unit arrangement, paying special attention to the lateral geomorphic relationships between marine and terrestrial morphosedimentary units developed during interglacials under sea-level highstand scenarios. The interglacials occurred during four key Quaternary periods might be related with major gradual changes associated with glacial climate cycles reported from marine and ice oxygen-isotope records. Almost coeval changes in geomorphological styles are reported from all studied areas, regardless of their specific geodynamic context. Results from the Mediterranean realm suggest that this area is more sensitive to climatic and sea level variability than the Spanish Atlantic coast, particularly in the case of rapid and abrupt changes.