Evidence for mid-holocene environmental change in the western Khabur drainage, northeastern Syria

Vegetation on the semi-arid steppe of northern Syria responds quickly to fluctuations in patterns of precipitation and even small shifts may preclude subsistence agriculture. Archaeological survey in the western Khabur drainage has revealed periodic human settlement that responded to these fluctuations. During the late fifth-early fourth millennium B.C. the wadis held water perennially, indicating a more favorable water balance than today. Sites of this period were then buried beneath two meters of sands and gravels before the surface stabilized in the early third millennium. During this period, the numerous sites as large as 30 hectares indicate excellent conditions for agriculture. Shortly after 2500 B.C.,all these sites were abandoned and the region was not again resettled until the first millennium. Subsequent occupations occured during the Roman/Byzantine and Islamic periods (after A. D. 622). The short periods of settlement were each separated by 1000 or more years of abandonment. After Medieval times, until recently, the: region was occupied primarily by nomadic tribes of sheep herders. Changes in precipitation patterns probably account for some of these changes in the landscape and human settlement.