Publication Date:
2019-07-26
Description:
Progresses in understanding the sedimentary dynamic of the Western Alboran Basin lead us to propose a model of evolution of its tectonic inversion since the Pliocene to present-time. Extensive and strike-slip structures accommodate the Miocene back-arc extension of the Alboran Basin, but undergo progressive tectonic inversion since the Tortonian. Across the Alboran Basin, the Alboran Ridge becomes a transpressive structure accommodating the shortening. We map its southwestern termination: a Pliocene rhombic structure exhibiting series of folds and thrusts. A younger structure, the Al-Idrissi fault zone (AIF), is Pleistocene to present-day active strike-slip fault zone. This fault zone crosses the Alboran Ridge and connects southward to the transtensive Nekor Basin and the Nekor fault. In the Moroccan shelf and at the edge of a submerged volcano, we date the inception of the local shelf subsidence from the 1.81–1.12 Ma. It marks the propagation of the AIF toward the Nekor Basin. Pliocene thrusts and folds and Quaternary transtension appear at first sight as different tectonic periods but reflects the long-term evolution of a transpressive system. Despite a constant direction of Africa/Eurasia convergence since 5 Ma at the scale of the southern margin of Alboran Basin, the Pliocene-Quaternary inversion evolves from transpressive to transtensive on the AIF and the Nekor Basin. This system reflects the expected evolution of the deformation of the Alboran Basin under the indentation of the African lithosphere.
Electronic ISSN:
1869-9537
Topics:
Geosciences
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