Stable isotopic signatures from tufa carbonates: Providing environmental context for Palaeolithic archaeology and palaeorainfall composition data to validate climate

The Wadi Dabsa basin in the Harat Al Birk contains the richest locality of Palaeolithic artifacts (2.970) in southwestern Saudi Arabia, and it is pivotal region hominins dispersals out of Africa. Extensive tufa carbonates, including a partially tufa-encased basalt hand-axe, indicate a wetter basin in the past, which would have been attractive to prey and hominins. Analysing the stable isotopes of already field-collected tufa will reveal information about past source moisture composition and palaeotemperature (preliminary U-Th dates indicate Last Interglacial ages). These isotopic data also represent a rare dataset to help validate numerical climate models using simulations of the past.

This project aims to provide a palaeoenvironmental record of source moisture composition and palaeotemperature during the deposition of tufa at the key archaeological site of Wadi Dabsa site, Harat Al Birk, Saudi Arabia. This aim will be achieved via stable isotopic analysis of the tufa carbonates (samples already collected), which have U-Th ages during substages of the Last Interglacial, also known as Marine Oxygen Isotope Stage (MIS) 5, (130-82 thousand years ago), and also during MIS 7.

The objectives of this analysis are to provide the first:
1) reconstruction of palaeoenvironmental conditions within the Wadi Dabsa basin, giving environmental context to the Palaeolithic, and later lithic, artifacts which represent the largest assemblage at the southern Red Sea coast. In particular, stable isotopic signatures will reveal information about the composition of the source moisture (rainfall) for the tufa carbonate and temperature of the water within the basin.
2) palaeo-isotopic dataset for past rainfall the western coast of the Arabian Peninsula.

These data, along with ongoing analysis by Richard Clark-Wilson (R.C-W.) and Ian Candy (I.C.) of carbonate-rich sites in the interior (e.g. the western Nefud Desert in Saudi Arabia) and published data from speleothems in Oman and Yemen, will allow us to test numerical climate model simulations of rainfall composition over the Arabian Peninsula for the Last Interglacial for the very first time. The palaeodata-modelling comparisons are vital to validate numerical climate models, which are then used to make future climate predictions.