Hercynian compressional deformations of the Ahnet–Mouydir Basin, Algerian Saharan Platform: far‐field stress effects of the Late Palaeozoic orogeny

Haddoum, Hamid; Guiraud, René; Moussine‐Pouchkine, Alexis

doi:10.1046/j.1365-3121.2001.00344.x

Cited by 70 publications

(47 citation statements)

References 34 publications

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“…According to Helg et al (2004), Caritg et al (2004) and Burkhard et al (2006), the Anti-Atlas should be regarded as an unusual type of fold belt due to a generalized thick-skinned style and an abundance of weak layers in the Paleozoic sedimentary pile. The particular interest of the Eastern Anti-Atlas is its location at the intersection between the NW-SE Ougarta chain (Haddoum et al 2001) and the ENE-WSW main body of the Anti-Atlas (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Inversion tectonics, interference pattern and extensional fault-related folding in the Eastern Anti-Atlas, Morocco

Robert-Charrue

Burkhard

2008

Swiss J. Geosci.

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The Anti-Atlas belt of Morocco is a Variscan chain which appears as a huge anticlinorium oriented NE-SW. In the internal part of this structure, the actual relief shows the basement cropping out as inliers (Piqué 2001) or boutonnières. The cover, a thick pile of Paleozoic sediments up to 12 km thick, is gently folded and of low grade metamorphism in its lower level. The lack of major décollement, of a deformation front or thrust-fault makes the Anti-Atlas an unusual type of belt, which does not fit with classic schemes. The Anti-Atlas has been considered to be a thick skinned fold belt, with the crystalline basement involved in the horizontal shortening and where the folding of the cover fits to a "buckle fold" mode . This structural style is determined by two key parameters: the total thickness of Paleozoic cover series and the relative abundance of shale vs. competent marker beds.The Eastern Anti-Atlas has particular features which are not found elsewhere in the Anti-Atlas. Its location at the intersection between the NW-SE Ougarta chain and the ENE-WSW main body of the Anti-Atlas, produces an egg-box interference pattern. The significance of minor folds and thrusts in the competent beds and their particular orientation is examined. The fact that the cover in the Eastern Anti-Atlas is only 6 km thick, which changes the shale vs competent beds ratio, influences its structural style. The feature that distinguishes the most Eastern Anti-Atlas is the presence of large E-W normal faults affecting the whole structure and creating extensional fault-related folding in the cover. IntroductionThe Moroccan Anti-Atlas belt (Choubert & Faure-Muret 1971) (Fig. 1) is located along the northern border of the WestAfrican Craton (WAC), between the Tindouf Paleozoic basin to the South and the High Atlas to the North. The latter results from a Cenozoic inversion of a Mesozoic basin (Frizon de Lamotte et al. 2000). Laterally limited by the Atlantic Ocean to the South-West, the Anti-Atlas s.s. disappears eastward below an Upper Cretaceous-Cenozoic plateau (the so-called "Hamada du Guir") in the Tafilalt region (Fig. 2). The Anti-Atlas possibly corresponds to a Paleozoic foreland fold-belt, which can be regarded as the deformed foreland of the Variscan chain present in Morocco in the "Moroccan Meseta" (Hoepffner et al. 2006;Raddi et al. 2007) (Fig. 1). According to Helg et al. (2004 and Burkhard et al. (2006), the Anti-Atlas should be regarded as an unusual type of fold belt due to a generalized thick-skinned style and an abundance of weak layers in the Paleozoic sedimentary pile. The particular interest of the Eastern Anti-Atlas is its location at the intersection between the NW-SE Ougarta chain (Haddoum et al. 2001) and the ENE-WSW main body of the Anti-Atlas (Fig. 1). The aim of this study is, on the one hand, to analyse the structural pattern resulting from this interference and, on the other hand, to discuss the age and tectonic significance of large E-W normal faults, which are described here for the first time.Detaile...

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Section: Introductionmentioning

confidence: 99%

Inversion tectonics, interference pattern and extensional fault-related folding in the Eastern Anti-Atlas, Morocco

Robert-Charrue

Burkhard

2008

Swiss J. Geosci.

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“…In contrast, the calibration and dating of metamorphism are still poorly documented: see Bonhomme & Hassenforder (1985), Buggish (1988), Belka (1991), Magroum in Soulaimani and Piqué (2004), Sebti et al (2008) and Ruiz et al (2008). The Ougarta belt and Bechar Basin structures are discussed by Donzeau (1974), Kazi-Tani et al (1991), Haddoum et al (2001), andFabre (2005). Further references about the geodynamic interpretation are given in Sect.…”

Section: The Variscan Tectonicsmentioning

confidence: 99%

The Variscan Belt

Michard

Hoepffner

Soulaı̈mani

et al.

Continental Evolution: The Geology of Morocco

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“…They were weakly folded and faulted during the Variscan orogeny in latest Carboniferous/earliest Permian times (Donzeau et al 1981;Haddoum et al 2001;Guiraud et al 2005). The deformation is most pronounced in the Ahnet and decreases towards the east and northeast (Mouydir and Illizi Basin).…”

Section: Geological Settingmentioning

confidence: 99%

“…data, 1970), showing the extension of Carboniferous strata as well as the location of sections and sample localities, number coding of sections, and sample localities as used in the text and in the appendices Facies (2009) 55:443-472 445 uplift and erosion in the late Early Devonian (Emsian). The Middle Devonian (Eifelian) transgression marks the onset of a new cycle that is characterized by the establishment of shallow-marine intracratonic basins and intervening ridges (Wendt et al 2006) which image ancient, rejuvenated lineages (Haddoum et al 2001). This palaeogeographic configuration was leveled by a widespread playa and delta sedimentation during the Famennian and early Tournaisian.…”

Section: Geological Settingmentioning

confidence: 99%

Carboniferous stratigraphy and depositional environments in the Ahnet Mouydir area (Algerian Sahara)

Wendt

Kaufmann

Bełka

et al. 2009

Facies

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An up to 3,000-m-thick pile of Carboniferous rocks covers the northern fringe of the Precambrian Hoggar Massif (Touareg Shield) in southern Algeria, thus terminating the depositional history of the Palaeozoic in this sector of the North African Craton. The previous Devonian (Eifelian to Frasnian) palaeogeographic configuration of the area, characterized by ridges and shallow basins, is leveled by a widespread Famennian playa and lower Tournaisian delta sedimentation on a largely undifferentiated shelf. Tournaisian to Moscovian strata were deposited under open-marine, deltaic, shallow-subtidal, fluvial, and continental environments. The Carboniferous sequence can be subdivided into 12, largely interfingering, lithostratigraphic formations, which were dated by conodonts, ammonoids, foraminifers, and brachiopods, yielding a modified biostratigraphic framework of the area. The formations are stacked in four transgressive-regressive cycles, which include two major gaps, one during the middle Tournaisian, the other during the middle Visean to Serpukhovian. The oscillations of sea level can be traced into neighboring areas and seem coeval to early pulses of the Late Carboniferous/Early Permian glaciation of Gondwana. To a lesser degree they may reflect more local tectonic effects of the Variscan orogeny.

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Hercynian compressional deformations of the Ahnet–Mouydir Basin, Algerian Saharan Platform: far‐field stress effects of the Late Palaeozoic orogeny

Cited by 70 publications

References 34 publications

Inversion tectonics, interference pattern and extensional fault-related folding in the Eastern Anti-Atlas, Morocco

Inversion tectonics, interference pattern and extensional fault-related folding in the Eastern Anti-Atlas, Morocco

The Variscan Belt

Carboniferous stratigraphy and depositional environments in the Ahnet Mouydir area (Algerian Sahara)

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