Further evidence for a relatively high sea level during the penultimate interglacial: open-system U-series ages from La Marina (Alicante, East Spain)

Abstract

The elevation and timing of high sea stands during Oxygen Isotope Stage (OIS) 7 are not as well constrained as those of OIS 5e. Conflicting values are reported from Mediterranean coastlines, and fossil dating is inaccurate because of ubiquitous open U-series systems. New morphostratigraphic data from La Marina (eastern Spain) supported by open-system U-series coral ages shed light on the maximum sea level during OIS 7. Fossil corals (Cladocora caespitosa) underlying an OIS 5e marine unit yielded U-series ages from 178 ± 10 to 208 ± 11 ka (±2s; n=7) with an outlier at 240 ± 18 ka. Mean open-system limit ages of 170 ± 10 (minimum age after correction for 234Th -230Th uptake) and 237 ± 20 ka (maximum age after correction for 238U - 234U uptake) were calculated to have a probable age closer to the minimum value, for an assignment of OIS 7a or 7c. The occurrence of a warm-water “Senegalese” fauna (Strombus bubonius) in OIS5e and OIS 7 marine units confirms the arrival of tropical species to the Mediterranean before the last interglacial period. Morpho-sedimentological and neotectonic studies suggest that the maximum paleo-sea level during OIS 7c or 7a was a few meters below that of OIS 5e.