Tectono-stratigraphy of the Shushan Basin, Western Desert, Egypt: A window into the evolution of the SE Mediterranean province

Abstract

The SE Mediterranean is a key region documenting the geological history of the Mesozoic Tethys Ocean while comprising one of the most promising provinces in the world in terms of energy resources. Using 2D seismic reflection data tied to exploration wells, this work analyses the Shushan Basin of northern Egypt within a context dominated by continental rifting, ocean propagation, and closure of the Tethys Ocean. Nine (9) seismic megasequences and four (4) major structural trends are identified in the Shushan Basin. In the centre of the basin, the interpreted megasequences document four (4) major tectonic episodes: i) a Paleozoic early-rift stage, ii) a syn-rift stage lasting from the Early Jurassic to the Early Cretaceous, iii) an Aptian-Cenomanian post-rift stage, and iv) a syn-compressional phase that started in the Late Cretaceous and ended in the Miocene. Importantly, the data in this work suggest the presence of up to 1.6 km of Upper Paleozoic-Triassic strata below the Lower Jurassic Ras Qattara Formation. Widespread extension occurred from the Late Triassic to the Early Cretaceous, a period of time in which graben and half-graben basins were formed and delimited by E-W and NW-SE striking faults. Later in the basin's evolution, mild tectonic reactivation predominated and was accompanied by a (post-rift) thermal episode in Northern Egypt. As a corollary, we show that the tectonic episodes interpreted in this work reflect the position of the Shushan Basin near the junction between the southern margin of the Tethys Ocean, the Syrian Arc system, and the Red Sea continental rift. Consequently, regional faults interpreted in this work are grouped into four families with distinct trends: i) Red Sea, ii) Tethyan, iii) Syrian Arc, and iv) Aqaba.