Miocene polyphase tectonic evolution of the southern edge of the Mitidja basin (north-central Algeria) inferred from a cross section of the Hammam Melouane region

Abstract

The Mitidja basin is a Neogene post-nappe basin in northern Algeria that underwent tectonic deformation during the Miocene. In the current contribution, we study the geology and structure of the representative Hammam Melouane region in the southern margin of the Mitidja basin to ascertain the tectonic and structural evolution of the region and Mitidja basin within Miocene period. Our geological field data and structural analyses suggest polyphase tectonic deformation during the late Burdigalian to Tortonian (20.44–7.24 Ma). Prominent structures in the study area include folds and fractures (joints and faults) at various scales. These structures were created during two main tectonic phases: (1) a NW−SE late Burdigalian extensional phase, characterized by the development of normal faults, synsedimentary fracturing, and thin-section scale grabens; and (2) a NNW−SSE Tortonian inversion phase, during which a compressional regime produced folds and reverse, thrust, and strike-slip faults. This Miocene polyphase tectonic evolution of the southern edge of the Mitidja basin was the response to the convergence of the Africa-Eurasia plates which began during the Cretaceous and continues to present day.