Late Tertiary Channel System in Northern Libya and Its Implications on Mediterranean Sea Level Changes

Abstract

A large fossil drainage system of probable upper Miocene age is recognized along the northeastern flank of the Sirte Basin, northern Libya. The main channel has been traced for about 150 km eventually being lost under the sarir, just south of Qasr as Sahabi. It has cut into middle Miocene limestone to a depth of over 1300 feet. In this region the surface is near present sea level. It is postulated that the Sahabi drainage system is the result of an abrupt drop in Mediterranean sea level of at least 1300 feet, and probably more than 2000 feet, during the late Miocene. During the early Pliocene, the sea returned to a level about the same as, or a little less than, that just prior to the late Miocene regression. Other possible late Miocene drainage systems have been recorded in eastern Libya and the western Desert of Egypt; these may be related to the same sequence of late Tertiary events that affected a great portion of the eastern Mediterranean region. These Neogene geomorphic features of northeastern Africa, which have long been a perplexing problem, now fit well into an hypothesis which accommodates much of the new data obtained from drilling beneath the floor of the Mediterranean Sea.