Sedimentary evolution and palaeogeography of mid-Jurassic deposits of the Central High Atlas, Morocco

Addi, Abdellah Ait; Chafiki, Driss

doi:10.1016/j.jafrearsci.2013.04.002

Cited by 32 publications

(9 citation statements)

References 38 publications

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“…From Toarcian times, carbonate platforms developed in the margins of the central High Atlas basin [ Pierre et al, ; Amour et al, ], whereas the basin axis was occupied by a mixed carbonate‐siliciclastic platform system prograding eastward to basinal deposits [ Frizon de Lamotte et al, ]. This mixed system progressively graded to an extensive shallow water carbonate platform of Bajocian to lower Bathonian in age that is recognized throughout the central High Atlas [ Ait Addi and Chafiki, ].…”

Section: Jurassic Central High Atlas Diapiric Provincementioning

confidence: 99%

Diapiric growth within an Early Jurassic rift basin: The Tazoult salt wall (central High Atlas, Morocco)

et al. 2017

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The central High Atlas (Morocco) constitutes a diapiric province that hosts a complex array of elongated diapirs and minibasins that formed during the Lower Jurassic rift of the Atlas Basin. This paper aims to study the structure and growth evolution of the Tazoult diapiric wall, located in the central High Atlas, by means of structural and sedimentological fieldwork integrated with remote sensing mapping. The Tazoult salt wall is a 20 km long × 3 km wide NE‐SW trending ridge that exposes Upper Triassic red beds and basalts along its core. The succession flanking the salt wall ranges from Hettangian to Bajocian ages displaying spectacular sedimentary wedges in the SE and NW flanks. The Hettangian‐early Sinemurian carbonates mainly crop out as blocks embedded in the core rocks. The ~1 km thick Pliensbachian platform carbonates display large subvertical flap structures along the flanks of the Tazoult salt wall with unconformities bounding tapered composite halokinetic sequences. In contrast, the ~2.5 km thick late Pliensbachian‐Aalenian mixed deposits form tabular composite halokinetic sequences displaying small‐scale hook halokinetic sequences. Passive diapirism resulted in the lateral extrusion of the evaporite‐bearing rocks to form an allochthonous salt sheet toward the adjacent SE Amezraï minibasin. The Bajocian platform carbonates partially fossilized the Tazoult salt wall and thus constitute a key horizon to constrain the timing of diapir growth and discriminate diapirism from Alpine shortening. The Pliensbachian carbonate platform evolved as a long flap structure during the early growth of the Tazoult salt wall, well before the onset of the Alpine shortening.

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Section: Jurassic Central High Atlas Diapiric Provincementioning

confidence: 99%

Diapiric growth within an Early Jurassic rift basin: The Tazoult salt wall (central High Atlas, Morocco)

et al. 2017

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“…Representing an ENE-WSW trending intracontinental fold-thrust belt, the High Atlas Mountain range was formed during the Cenozoic by the inversion of a Fig. 1 Geological location map (modified from Saadi et al, 1985 andChafiki, 2013) Oldest Gondwanan record of Strophodus Triassic-Jurassic rift system (Beauchamp et al, 1996;Frizon de Lamotte et al, 2008;Jacobshagen et al, 1988). The basinal fill of this rift system, which was initiated by the opening of the North Atlantic Ocean as the result of the dislocation of Pangaea, mainly consists of Early and Middle Jurassic marls and limestones with intercalated carbonate build-ups referred to the Agoudim and Tazigzaout formations (Ait Addi, 2000Ait Addi & Chafiki, 2013).…”

Section: Geological and Stratigraphic Frameworkmentioning

confidence: 99%

“…1 Geological location map (modified from Saadi et al, 1985 andChafiki, 2013) Oldest Gondwanan record of Strophodus Triassic-Jurassic rift system (Beauchamp et al, 1996;Frizon de Lamotte et al, 2008;Jacobshagen et al, 1988). The basinal fill of this rift system, which was initiated by the opening of the North Atlantic Ocean as the result of the dislocation of Pangaea, mainly consists of Early and Middle Jurassic marls and limestones with intercalated carbonate build-ups referred to the Agoudim and Tazigzaout formations (Ait Addi, 2000Ait Addi & Chafiki, 2013). The upper Agoudim Formation corresponds to the Agoudim Members III and IV, whose stratigraphic range is early to probably late Bajocian (Ait Addi, 2015;Bodin et al, 2017).…”

Section: Geological and Stratigraphic Frameworkmentioning

confidence: 99%

The oldest Gondwanan record of the extinct durophagous hybodontiform chondrichthyan, Strophodus from the Bajocian of Morocco

et al. 2023

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Strophodus is a speciose and geographically widespread taxon of large durophagous hybodontiform chondrichthyan, with a stratigraphic range extending from Middle Triassic to the Early Cretaceous. Here, we describe a new species of Strophodus, S. atlasensis sp. nov., based on an incomplete articulated dentition recovered from marine Bajocian deposits of the eastern High Atlas Mountains in Morocco. The new species is diagnosed by a unique combination of dental characters that includes, among others, the presence of triangular first lateral teeth, mesio-distally wide and bulbous second lateral teeth without an occlusal crest or dome and uniquely shaped first posterior teeth that are shorter mesio-distally than being labio-lingually long, as well as small second posterior teeth whose roots protrude below the crowns to meet each other in an efficient interlocking manner. The holotype and only specimen of Strophodus atlasensis sp. nov. represents the hitherto oldest known record of Strophodus from Gondwana and the first record of that genus from the Bajocian, thus adding valuable novel information to our incomplete understanding of the evolutionary history of extinct hybodontiform chondrichthyans.

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“…The deposits are marls, limestones, and gravity‐flow deposits corresponding to ramp‐type to a shoal‐rimmed morphology, while the basin deepened and the fault movement accelerated (Quiquerez et al, ; Wilmsen & Neuweiler, ). The Toarcian‐Early Bajocian is characterized by a shallowing‐upward cycle that begins with Toarcian marls and marly shales with ammonites and ends with shallow marine carbonate constructions and reefs (Ait Addi & Chafiki, ). This reflects increasing topography of the ridges and deepening of the depocenters in the central areas.…”

Section: Geology Of the High Atlasmentioning

confidence: 99%

Evolution of the Ridges of Midelt‐Errachidia Section in the High Atlas Revealed by Paleomagnetic Data

et al. 2018

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New paleomagnetic data (43 sites) from Mesozoic sediments are contributed in this work, verifying the presence of a pervasive syntectonic Early Cretaceous remagnetization in the easternmost area of the Moroccan High Atlas. Using the small circle intersection method, we have calculated the characteristic remagnetization direction (Dec: 337.3, Inc: 38.4) that fits with a 100‐Ma age, according to the Apparent Polar Wander Path of Africa. The paleomagnetic vectors of remagnetization are used to obtain the geometry during the remagnetization stage (100 Ma) of one of the most renowned geological cross sections of the High Atlas, the Midelt‐Errachidia profile. The partial restoration of the cross section at 100 Ma allows us to determine the dips of the beds at the remagnetization stage in five structures (ridges or anticlines). Our results indicate that the five ridges that configure the Midelt‐Errachidia profile were initiated to different degrees prior to wholesale compressive deformation during the Cenozoic. This configuration can be explained according to two different scenarios that we discuss in this paper: transpression and diapirism. The geological model obtained, both at present and at 100 Ma, indicates the existence of a Mesozoic cover substantially décolled from the Paleozoic basement, what strongly contrasts with previously published transects of the same area.

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Sedimentary evolution and palaeogeography of mid-Jurassic deposits of the Central High Atlas, Morocco

Cited by 32 publications

References 38 publications

Diapiric growth within an Early Jurassic rift basin: The Tazoult salt wall (central High Atlas, Morocco)

Diapiric growth within an Early Jurassic rift basin: The Tazoult salt wall (central High Atlas, Morocco)

The oldest Gondwanan record of the extinct durophagous hybodontiform chondrichthyan, Strophodus from the Bajocian of Morocco

Evolution of the Ridges of Midelt‐Errachidia Section in the High Atlas Revealed by Paleomagnetic Data

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