Deformations synsedimentaires en compression pendant le Lias superieur et le Dogger, au Tizi n'Irhil (Haut Atlas central de Midelt, Maroc)

Studer, M.; Dresnay, Renaud du

doi:10.2113/gssgfbull.s7-xxii.3.391

Cited by 44 publications

(22 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…FEDAN, 1988;CHARPdER~, 1990;HAUPTMANN, 1990). Excessive values of 8000 m, as reported by STUDER (1980) for the Jurassic beds in parts of the central High Atlas, were not generally accepted up to now.…”

Section: Permian-bajocianmentioning

confidence: 89%

Inversion tectonics of intracontinental ranges: High and Middle Atlas, Morocco

Giese¹,

Jacobshagen²

1992

Geol Rundsch

View full text Add to dashboard Cite

ZusammenfassmlgDer Hohe und der Mittlere Atlas sind intrakontinentale Gebirge im mobilen Vorland des mediterranen Rif-Orogens. Ihre Entwicklung weist drei Perioden auf: Die erste (Perm-Bathonium) kulminierte im Lias mit der Bildung von Riftgr~iben entlang spfitvariskischer Bruchzonen und Tholeiit-Ergtissen. Im Intervall Callovium-Eoz~in deuten tektonische Beruhigung und geringere Sedimentation auf eine allmfihliche Abktihlung der Lithosphfire hin. Seit dem Oligoz~in steht die Region unter Kompression. Der Hohe und der Mittlere Atlas haben sich zeitgleich mit den Hauptphasen der Kompression im Rif herausgehoben. Refraktionsseismische Untersuchungen haben einen fiachen Lagenbau der Kruste mit mehreren low-velocity-Zonen aufgewiesen, deren tiefste mit einer Zone hoher elektrischer Leitf~ihigkeit zusammenffillt und als bedeutende Abscherungszone gedeutet wird.Aus der geotektonischen Entwicklung des Hohen und des Mittleren Atlas und aus der heutigen Krustenstruktur wird folgendes Modell abgeleitet: In der frtthmesozoischen Rift-Phase wurde die Kruste fiber den Mantel-Aufw61bungen dutch Zerrungsbrtiche und durch Zergleiten an subhorizontalen Scherfl~ichen ausgedfinnt. W~ihrend der k~inozoischen Kollisionen im Rif-Atlas wurden diese Scherfl~ichen dann gegenlfiufig bewegt, die Riftgraben-Ftillungen dabei bis zu geringer Krustenverdickung eingeengt und anschlieBend herausgehoben. Die Inversion der beiden Atlas-Gebirge ist somit nicht nur isostatisch bedingt, sonderu auch durch Aufpressung bei thick-and-thin-skinned-Tektonik verursacht. AbstractThe High and Middle Atlas are intracontinental mountain belts situated within the mobile foreland of the Mediterranean Rif orogen. They developed in three stages. The first period (Permian -Bathonian) culminated during the Lias with extended rift grabens and tholeiite extrusions. From Callovian to Eocene, the tectonic activity and the rates of sedimentation were reduced, both pointing to a cooling of the lithosphere. Since the Oligocene, the whole region is submitted to compressional stress. The High and the Middle Atlas were uplifted within two phases, which were correlated with main phases of Rif orogenesis. Refraction seismic measurements have recently revealed there a flat layered structure of the crust with several low velocity zones. The deepest one coincides with a layer of high electric conductivity, which is interpreted as a zone of detachment.From the geotectonic evolution of the High and Middle Atlas and from the structure of the crust, the following model was deduced: During Early Mesozoic rifting, the crust on top of the mantle elevations was thinned by both extensional fracturing and by gliding along intracrustal detachment planes. During the Cenozoic collisions of the Rif, these shear planes were reactivated by thrusting in opposite directions. Compressional deformation of the graben fillings led now to a moderate thicken-*) Authors' address: E GmsE, V. JACOBSHAGEN,

show abstract

Section: Permian-bajocianmentioning

confidence: 89%

Inversion tectonics of intracontinental ranges: High and Middle Atlas, Morocco

Giese¹,

Jacobshagen²

1992

Geol Rundsch

View full text Add to dashboard Cite

show abstract

“…Early in the Toarcian, a renewed crustal extension disrupted the Early and Middle Liassic carbonate platform (El Hammichi et al, 2002) and led to the development of the fault-bounded Middle and High Atlas troughs. These faulted basins are composed of a mosa€ ıc of rhomb-shaped depocentres bounded by synsedimentary anticline ridges (Studer and du Dresnay, 1980). They were initiated by transtensional tectonics accompanied by magmatic intrusions of MidJurassic age (Laville, 1988).…”

Section: The Atlasic Rifting: State Of the Questionmentioning

confidence: 99%

“…The Middle and High Atlas troughs are both characterized internally by a mosaic of rhomb-shaped depocentres bounded by synsedimentary ridges (Studer and du Dresnay, 1980), sometimes occupied by plutonic rocks exibiting rhomb-shaped or gashed networks. These structures were initiated by transtensional tectonics accompanied by the emplacement of intrusions of MidJurassic age (Laville, 1988).…”

Section: The Atlasic Trough Episodementioning

confidence: 99%

A restatement of the Mesozoic Atlasic Rifting (Morocco)

Laville

Piqué

Amrhar

et al. 2004

Journal of African Earth Sciences

162

View full text Add to dashboard Cite

“…The principal tectonic stages underwent by the Central High Atlas are documented by numerous authors, but there is a controversial point in the tectonic activity during the Mesozoic. This debate is open since Jacobshagen et al () exposed that inversion processes started at the end of the Oligocene (Laville & Piqué, ), thus contradicting Studer and Du Dresnay () that pointed out intra‐Jurassic compressional movements. Mesozoic, syn‐sedimentary movements were first described by Dubar () and related to Late Liassic and Middle Jurassic horizontal compression by Studer and Du dresnay ().…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

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.

show abstract

Deformations synsedimentaires en compression pendant le Lias superieur et le Dogger, au Tizi n'Irhil (Haut Atlas central de Midelt, Maroc)

Cited by 44 publications

References 0 publications

Inversion tectonics of intracontinental ranges: High and Middle Atlas, Morocco

Inversion tectonics of intracontinental ranges: High and Middle Atlas, Morocco

A restatement of the Mesozoic Atlasic Rifting (Morocco)

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

Contact Info

Product

Resources

About