No evidence from the eastern Mediterranean for a MIS 5e double peak sea-level highstand

To understand past and future sea-level variability, it is important to know if during an interglacial the eustatic sea level is constant or oscillates by several meters around an average value. Several field sites within and outside the tropics have been interpreted to suggest such oscillations during Marine Oxygen Isotope Stage (MIS) 5e (129–116 ka). Here, we present our analysis of one such non-tropical site, Hergla, where a facies succession indicates two foreshore deposits above each other, previously interpreted as MIS 5e sea-level highstand amplified by a second rise. Our study, based on field, microfacies, and optical age Bayesian statistics shows a sea-level rise forming the upper foreshore strata that coincided with the global sea-level rise of the MIS 5a interstadial. The site does therefore not provide evidence for the MIS 5e double peak. We conclude from our analysis that the facies-based proxy is insensitive to small-scale sea-level oscillation. Likewise, uncertainties associated with age estimates are too large to robustly infer a short-term sea-level change

Coastal response to climate change: Mediterranean shorelines during the last interglacial (MIS 5)

The response of shorelines to climate change is controlled by fall and rise of the sea level and by the alteration of the coastal environment due to changing fluvial discharge and biological activity. In the Mediterranean this response is complicated by the geographic proximity of the North Atlantic and the African Monsoon climate systems, by a time and space specific interaction of eustatic and waterload components of sea level and by the mid-latitudinal time lag between orbital forcing and terrestrial response. Here, six Mediterranean coastal records are presented which contribute to our understanding of how mid-latitudinal coasts respond to orbital forcing. The sediment sequences show sharp switches between siliciclastic- and carbonate-dominated nearshore environments where carbonate-rich sediments are composed of oolitic grainstones. From modern analogues it is deduced that the oolitic sediments represent a period of relatively high annual sea-surface temperature and lack of fluvial discharge. The warm-arid period was recorded at ~ 114 ka on the southeast Iberian coast, at ~113 ka on the Levant coast, at ~110 ka on the coast west of the Nile delta and at ~83 ka on the north Saharan coast. It lasted 10 20 ka in east (Levant coast) and west (Iberian coast) and lasted 40 ka or more in the central-south of the east Mediterranean. Timing and duration of the coastal proxy allow inferring instantaneous and dominant response to external forcing in the east and west and delayed and prolonged response due to dominant regional forcing in the centre of the East Mediterranean. A 9 m eustatic sea-level highstand during MIS 5e is suggested with a start of the subsequent sea-level fall at ~118 ka while evidence for multiple MIS 5e highstand and a highstand during MIS 5a remain elusive