Anticline growth by shortening during crustal exhumation of the Moroccan Atlantic margin

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1016/j.jsg.2020.104125.

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Authors

David Fernández-Blanco , Mohamed Gouiza, Remi J.G. Charton , Christian Kluge, Jop Klaver, Kirsten Brautigam, Giovanni Bertotti

Abstract

It is unclear how the crustal-scale erosional exhumation of continental domains of the Moroccan Atlantic margin and
the excessive subsidence of its rifted domains affected the Late Jurassic-Early Cretaceous post-rift evolution of the
margin. To constrain the km-scale exhumation, we study the structural evolution of the Jbel Amsittene. This anticline is located on the coastal plain of the Moroccan Atlantic margin, and is classically considered to have been developed initially by halokinesis in the Late Cretaceous and by contraction during the Neogene. Contrarily, our structural analysis indicates that the anticline is a fault-propagation fold verging north with Triassic salts at its core and formed by shortening shortly after continental breakup of the Central Atlantic. The anticline grew by NNW-SSE to NNE-SSW contraction, as shown by syn-tectonic wedges, regional kinematic indicators and synsedimentary structures in Upper Jurassic to Lower Cretaceous rocks. It grew further and tightened during the Cenozoic, presumably in relation to the Atlas/Alpine contraction. Thus, our data and interpretation suggest that "tectonic-drives-salt" in the anticline early growth, which is coeval with the growth of other anticlines along the Moroccan Atlantic margin and widespread km-scale exhumation farther onshore. Anticline growth due to shortening argues for intraplate far-field stresses potentially linked to the geodynamic evolution of the African, American and European plates.

DOI

https://doi.org/10.31223/osf.io/u3g5j

Subjects

Earth Sciences, Physical Sciences and Mathematics, Tectonics and Structure

Keywords

Jurassic, Cretaceous, Essaouira-Agadir, Jbel Amsittene, syn-sedimentary faults, thickness

Dates

Published: 2019-01-10 12:12

Last Updated: 2020-07-05 12:45

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License

CC BY Attribution 4.0 International

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