Palaeoecological Reconstruction of the Bahariya Formation: A Coastal Wetland Ecosystem of Northern Gondwana During the Cretaceous

演化之聲
Mar 14
6 min read

The Bahariya Formation, located in what is now the Western Desert of Egypt, is one of the most significant fossil-bearing geological formations in Africa. It is particularly well known for its sediments dating to the Late Cretaceous Cenomanian stage, roughly 100 million years ago. Since the German palaeontologist Ernst Stromer first investigated this formation in the early twentieth century, it has become an important site for studies of dinosaur diversity and ancient ecosystems. Although most of Stromer's fossil collection was destroyed during the Second World War, recent research based on surviving specimens and newly discovered material has gradually reconstructed a complex ancient ecosystem that once occupied the northern Gondwanan coastline.

Geologically, the Bahariya Formation is divided into three members: the Gebel Ghorabi Member, the Gebel el Dist Member, and the El Heiz Member. Above it lies the Abu Roash Formation. Much of the sediment composing these strata originated from Neoproterozoic rocks located to the south, which underwent prolonged weathering and erosion before being transported into the basin. These sediments produced layers rich in iron ore and ferruginous concretions. Sedimentological characteristics indicate that this region once existed within a meso-tidal environment, where the difference between high and low tide ranged roughly between two and four meters. The sediments are generally fine-grained and rich in organic matter, although certain areas were influenced by stronger water currents. The entire Bahariya system included mangrove forests, estuaries, tidal flats, and inland freshwater river networks. This large coastal embayment has been referred to by researchers as the Bahariya Bight, extending along the northern Gondwanan coastline for more than 300 kilometers.