Recent uplift of the Atlantic Atlas (offshore West Morocco): Tectonic arch and submarine terraces

Type Article
Date 2017-06
Language English
Author(s) Benabdellouahed Massinissa1, 2, Klingelhoefer FraukeORCID2, Gutscher M. -A.1, Rabineau MarinaORCID1, Biari Youssef1, 2, 3, Hafid M.4, Duarte J. C.5, 6, 7, Schnabel M.8, Baltzer Agnes9, Pedoja K.10, Le Roy P.1, Reichert C., Sahabi M.3
Affiliation(s) 1 : IUEM, UMR6538, Lab Geosci Ocean, Rue Dumont Durville, F-29280 Plouzane, France.
2 : IFREMER, Dept Marine Geosci, ZI Pointe Diable, CS10070, F-29280 Plouzane, France.
3 : Univ Chouaib Doukkali, Fac Sci, Lab Geosci Marines & Sci Sols, URAC 45,BP 20, El Jadida 24000, Morocco.
4 : Fac Sci, Dept Geol, Lab Geophys & Environm, BP 133, Kenitra, Morocco.
5 : Univ Lisbon, Inst Dom Luiz, Fac Ciencias, P-1749016 Lisbon, Portugal.
6 : Univ Lisbon, Dept Geol, Fac Ciencias, P-1749016 Lisbon, Portugal.
7 : Monash Univ, Sch Earth Atmosphere & Environm, Melbourne, Vic 3800, Australia.
8 : Geozentrum Hannover, BGR, Stilleweg 2, D-30655 Hannover, Germany.
9 : Univ Nantes, CNRS UMR LETG 6554, Lab Geolittomer, F-44312 Nantes 3, France.
10 : Univ UCBN Caen, CNRS, UMR 6143 M2C, F-14000 Caen, France.
Source Tectonophysics (0040-1951) (Elsevier Science Bv), 2017-06 , Vol. 706-707 , P. 46-58
DOI 10.1016/j.tecto.2017.03.024
WOS© Times Cited 4
Keyword(s) Atlas Mountain belt, Tectonic arch, Moroccan passive margin, Submerged terraces, Uplift
Abstract

Re-examination of marine geophysical data from the continental margin of West Morocco reveals a broad zone characterized by deformation, active faults and updoming offshore the High Atlas (Morocco margin), situated next to the Tafelney Plateau. Both seismic reflection and swath-bathymetric data, acquired during Mirror marine geophysical survey in 2011, indicate recent uplift of the margin including uplift of the basement.

This deformation, which we propose to name the Atlantic Atlas tectonic arch, is interpreted to result largely through uplift of the basement, which originated during the Central Atlantic rifting stage - or even during phases of Hercynian deformation. This has produced a large number of closely spaced normal and reverse faults, “piano key faults”, originating from the basement and affecting the entire sedimentary sequence, as well as the seafloor.

The presence of four terraces in the Essaouira canyon system at about 3500 m water depth and “piano key faults” and the fact that these also affect the seafloor, indicate that the Atlantic Atlas is still active north of Agadir canyon.

We propose that recent uplift is causing morphogenesis of four terraces in the Essaouira canyon system. In this paper the role of both Canary plume migration and ongoing convergence between the African and Eurasian plates in the formation of the Atlantic Atlas are discussed as possibilities to explain the presence of a tectonic arch in the region. The process of reactivation of passive margins is still not well understood. The region north of Agadir canyon represents a key area to better understand this process.

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Benabdellouahed Massinissa, Klingelhoefer Frauke, Gutscher M. -A., Rabineau Marina, Biari Youssef, Hafid M., Duarte J. C., Schnabel M., Baltzer Agnes, Pedoja K., Le Roy P., Reichert C., Sahabi M. (2017). Recent uplift of the Atlantic Atlas (offshore West Morocco): Tectonic arch and submarine terraces. Tectonophysics, 706-707, 46-58. Publisher's official version : https://doi.org/10.1016/j.tecto.2017.03.024 , Open Access version : https://archimer.ifremer.fr/doc/00378/48975/