GEOMORPHOLOGICAL AND GEOLOGICAL CONSTRAINTS ON THE DEVELOPMENT OF EARLY BRONZE CHERT INDUSTRIES AT THE NORTHERN RIM OF THE AL JAFR BASIN, SOUTHERN JORDAN

Abstract

The northern rim of Al Jafr basin was the focus of a massive quarrying effort during the late Neolithic and Chalcolithic periods. At that time, massive volumes of chert were extracted from the Muwaqqar Chalk Marl and the Umm Rijam Formations that crop out in the Umm Rijam, Khuzayma and Al Athriyat mountains. The landscape of the region is marked by a 100 km long escarpment marking the hydrological divide between the Al Jafr and Al Hisa basins. This escarpment and associated buttes were the exposures from which the chert was extracted. This was done from the nodules of the Muwaqqar Chalk Marl Unit beds and from the beds of the Umm Rijam Formation. Various patterns of extraction were developed based on the nature of the geological formation. The soft marl and chalk of the MCM led to narrow and deep digging into the exposures. The hard limestone of the Umm Rijam formation led to wide and shallow extraction patterns. Hilltops on the plateau served as sites for stone workshops. These sites were readily accessible and apparently defendable. They probably served dual purposes; a place to work stone and as observation posts defending the stone extraction activities in the lower areas.