The Suq al Jum'ah Palaeowadi, an Example of a Plio-Quaternary Palaeo-valley from the Jabal Nafusah, Northwest Libya

Study of borehole data in the foothill region of the Jabal Nafusah shows that the Suq al Jum'ah palaeowadi, which cuts the jabal east of Gharyan, comprised a major drainage channel which extended in the subsurface far out from the jabal into the southern part of the Jifarah Plain. The channel is filled with sands and gravels. Basalt lava flows, channelled along the valley in outcrop for 36 km, extend for a further 48 km in the subsurface. The palaeowadi was possibly initiated in the Pliocene and appears to have been completely filled and abandoned by the end of the Pleistocene. During Holocene rejuvenation of the drainage system, the Wadi al Majanin developed as the major wadi in the region. It did not, however, excavate the palaeowadi but instead followed a different but roughly parallel northward trend.