Geomorphological and palaeoenvironmental investigations in the southeastern Arabian Gulf region and the implication for the archaeology of the region

During the Late Quaternary, the climate of Arabia has fluctuated between periods of higher rainfall and fluvial activity, dominated by the influence of the Indian Ocean Monsoon (IOM) and drier/arid conditions under the influence of the westerlies. This has left a rich legacy of landforms from which temporal and spatial patterns of environmental change are reconstructed. The coastal desert region of the southeastern Arabian Gulf has been a focal point for human settlement since ~ 8000 cal yr BP. The region is strategically located on an important trade route between two ‘cradles of civilization’, namely, Mesopotamia and the Indus. Changes in the evolution and modification of this landscape under varying climatic conditions have influenced humans living in and exploiting this landscape for food and water, raw materials and trade routes.In this study, geomorphological and palaeoenvironmental investigations are integrated to provide a framework of environmental change for the Late Glacial and early–mid Holocene periods against which the archaeology of the area can be set. The Late Glacial and earliest Holocene was characterised by intense aridity and accumulation of mega linear dunes driven by the Shamal winds. In the Arabian Gulf region, this continued into the earliest part of the Holocene, whilst southern Arabia was under the influence of the IOM.The monsoon rains migrated into the Gulf region between 8500–6000 cal BP. During this time, semi-nomadic herders occupied this region and grazing their animals in a landscape covered with C3 savanna grassland. The Neolithic peoples also practised hunting and fishing and the collection of shellfish was an important activity. Pottery shows links with Mesopotamia at this time.From 6000 cal BP the IOM retreated south and rainfall was derived from winterly westerly sources. Under drier conditions a switch occurred to a sparser cover of C4 grasses. From 4500 cal BP the climate became much drier with the development of stronger westerly summer Shamal winds and the reactivation of dunes across the region. An intense arid period occurred at 4100 BP which corresponds with major drought conditions in Mesopotamia and the Indus region, which led to major changes in society. This event occurs at a major transition in the Arabian Gulf Bronze Age archaeological record with a decline in population and trade. The last 4000 yr has largely been characterised by arid conditions similar to those found in the region today.