A radiogenic isotope framework to study palaeoaridity in the Middle East

Dust plays a vital role in global climate and environmental change by influencing the Earth’s radiation budget and providing nutrients to marine and terrestrial ecosystems. Modern dust emissions are dominated by North Africa, the Middle East and West Asia, which together provide ~80% of total global atmospheric dust. Geological deposits of dust can also act as valuable archives to study hydroclimate variability across a range of global states, with marine sediments in particular able to preserve high resolution and continuous records of past dust emissions. For example, dust preserved in Arabian Sea sediments has been used to provide climatic context for hominin evolution in East Africa, however, there is little understanding of where the deposited sediments originate and hence whether they truly record an African signal. Tracing the provenance of the lithogenic fraction in marine sediments is made particularly challenging by the lack of geochemical data in key potential source areas such as Mesopotamia, one of the most active dust emission regions in the Middle East. Here we present new radiogenic isotope data (Sr and Nd) from surface sediment samples, integrated with the satellite-derived dust source activation frequency (DSAF) maps and other published radiogenic data to characterise the geochemical fingerprint of dust-producing regions in the circum Arabian Sea. Our results provide a framework to trace sources of dust in geological archives including marine sediments, speleothems and ice cores and to identify the provenance of archaeological artefacts. We exemplify the utility of our approach by comparing our data to strategically positioned marine cores in the Arabian Sea to shed new light on key regional palaeoclimate reconstructions.