Chronological and seasonal constraints for the Holocene S1 tephra in the Eastern Mediterranean

Le résumé fourni par la source

The eastern Mediterranean region experienced large hydroclimatic shifts throughout the Holocene (11.6 ka to present). The region is located between the contrasting humid Mediterranean climate and the Saharo-Arabian desert belt. The important palaeoclimatic record of the Dead Sea (Levant) ICDP Dead Sea Deep Drilling Project (DSDDP) core provides detailed reconstructions into the hydroclimatic variability during this time. However, chronological uncertainties have prevented detailed insight into the regional climatic (a)synchronies with other palaeoclimatic records in the region. The use of tephra horizons as time-synchronous markers can provide insight into the spatial and temporal environmental response of this region to past abrupt climatic change. The identification of a widely dispersed volcanic ash from a volcanic eruption is a particularly powerful chronological tool to be used, as seen with the S1 tephra from Mt. Erciyes (Turkey). Here, we present the identification of a microtephra layer, visible only in thin section analysis, within varved sediments of the Dead Sea DSDDP record. Using major, minor and trace element analysis, this tephra has been identified as the S1 tephra. Though the S1 tephra has been found in the Dead Sea Ein Gedi shallow water core before (Neugebauer et al., 2017), this is the first time a ‘visible’ tephra layer has been found in the deep ICDP sediment lake record. Through thin section micro facies and XRF analysis, we can now confirm the season of the S1 eruption from Mt. Erciyes happened during the winter. The discovery of the S1 tephra in the well-dated part of the DSDDP record and at other sites across the Mediterranean, we have used Bayesian age-modelling to refine the age for this key tephrostratigraphic marker. As a result, this will enable further detailed insights into the timing of the African Humid period across the eastern Mediterranean region during the early Holocene.

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