Miocene–Quaternary stratigraphy and sedimentation along EL Daba'a Plateau, Northwestern coast of Egypt

Abstract

The current research investigates the stratigraphy, sedimentation, and neotectonics of the Miocene–Quaternary succession along El Daba'a Plateau, northwestern coast of Egypt. In order to unveil the environments of deposition in connection with paleoclimate and sea-level variations, the stratal architecture, including bed geometries, orientation, and field relationships, is highlighted. The field observations of five sections at El Daba'a Plateau reveal two formations: the lower one is the Marmarica Formation of Middle Miocene age, and the upper one is the Alexandria Formation of Quaternary carbonate aeolianites and inter-aeolianite deposits. The Marmarica Limestone Formation is subdivided into two members: the lower is the Oasis Member, and the upper is the Siwa Escarpment Member. A distinct disconformity separates the two formations, with the recognition of twelve lithofacies units (L1–L12) and thirteen microfacies associations (Mf1–Mf13). The Oasis Member belongs to the inner carbonate ramp siliciclastic-carbonate facies association (Mf1–Mf3), while the Siwa Escarpment Member belongs to the mid-ramp carbonate-dominated facies association (Mf4–Mf6). Seven microfacies (Mf7–Mf13) are tied to the Quaternary carbonate aeolianites and inter-aeolianite deposits. Evidence of Late Pleistocene normal faults, trending WNW-ESE, ENE-WSW, and NNW-SSE, has moulded the coastal geomorphology, with a general vertical uplift of up to 15 m. Results of the current work contribute to understanding the geology of the Mediterranean margin at the NW part of Egypt, which needs further studies.