Archaeological and Palaeoenvironmental Investigation of Upper Pleistocene human occupation in the Dhofar Mountains, southern Arabia

Arabia is situated at the nexus of three continents, connecting Africa, Asia, and Europe. Given this geographic position, the territory of southern Arabia may have served as an important pathway linking hominins throughout the Pleistocene. Indeed, many of our species' most diverse and ancient mitochondrial (mtDNA) and Y-chromosome (yDNA) genetic lineages cluster around the Arabian Peninsula, confirming that the subcontinent played a critical role in the evolution and expansion of modern humans. Some scholars have even documented traces of a human expansion back into Africa, suggesting that this pathway was a bidirectional conduit of population movement.

It is not surprising that the peninsula facilitated periodic population expansions. The drastically oscillating Upper Pleistocene palaeoclimate occasionally transformed Arabia's hyperarid desert interior into savannah grasslands incised by perennial rivers and playa lakes. The landscape was also dramatically altered by depressed sea levels that exposed the continental shelf along the Red Sea and within the Arabo-Persian Gulf basin, together exposing over one million square kilometres of land. In addition, reduced sea levels triggered increased freshwater upwelling across these emerged landscapes, creating stable refugia for Arabia's prehistoric inhabitants. Given this cyclical process of amelioration and desiccation, it is posited that Arabia served as a demographic pump by drawing in hunter-gatherers during favourable phases; conversely, causing them to contract back into geographically conscripted refugia at the onset of aridification. Challenging climatic conditions created a negative-feedback-loop, as environmental desiccation reduced landscape carrying capacity and exerted pressure on Arabian foragers.

This research project will investigate one such environmental refugium: the Dhofar Mountains in southern Oman. Even under the present arid climatic regime, the annual monsoon rains deposit up to 400 mm of rainfall during the summer months. Therefore, Dhofar is posited to have served as an important population retreat during climatic downturns. This is supported by new evidence from al-Hatab Rockshelter in Dhofar, where evidence of human occupation during the Terminal Pleistocene has been found - a hyperarid phase when the peninsula was previously thought to have been uninhabitable.

Research in Dhofar permits the exploration of a potentially important refugium to determine the local record of human occupation and what adaptive behaviours (if any) developed amidst the backdrop of a fluctuating palaeoclimate. A series of preliminary investigations conducted by the PI throughout the region have recorded dense and ubiquitous lithic surface scatters across the landscape, often found in association with ancient lake basins and relict drainage systems. Two in situ buried archaeological sites have been tested (al-Hatab rockshelter and Ras Aïn Noor), with several other deposits requiring test-pitting (see Figures 1, 2, and 3 in visual evidence). Weaving together geological landscape survey with archaeological excavation and radiometric dating, we will begin to reconstruct the sequence of Upper Pleistocene occupation in Dhofar to articulate the expansion and contraction of hunter-gatherer communities associated with this niche.