THE JURASSIC SYSTEM IN NORTHERN EGYPT: II. Depositional and tectonic regimes

Abstract

The results are outlined of a detailed sedimentological study made of the Jurassic succession presented in northern Egypt at surface and in the subsurface, largely on the basis of material from over 80 wells. With the benefit of a detailed stratigraphical scheme, it has become possible to map the distribution of fluvio‐deltaic, shelf and open‐marine facies belts. Changes in distribution of facies are attributed to the eustatic interaction between Nubian and Tethyan influences, and to the repeated movement of local faults. Active basins are identified on the basis of static facies. and stacked thick sequences. The pattern of syn‐depositional tectonic activity thus assembled is compatible with existing tectonic models for the Eastern Mediterranean region: indeed, it is used to improve them. The present continental margin to Egypt is shown to have formed during a period of westward‐propagating crustal rifting, over the late Pliensbachian‐Bathonian interval. Evidence is presented for a link between movements within the central/southern African craton, and the sequence of extensional and transtensional activity observed in Egypt during the Jurassic and the “Cimmerian” event. Faults accommodating this strain were mostly orientated NE‐SW, that is, contiguous with the “Syrian Arc”.