Les couches rouges du Jurassique moyen du Haut Atlas central (Maroc); Correlations lithostratigraphiques, elements de datations et cadre tectono-sedimentaire

Jenny, Jacques; Marrec, Alain Le; Monbaron, Michel

doi:10.2113/gssgfbull.s7-xxiii.6.627

Cited by 74 publications

(33 citation statements)

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“…6, 6). In the Southern Subatlas Zone near Telouat (SCHILLING, 1990) and farther to the North at Jb el Igoudlane (JENNY et al, 1981) …”

Section: The Jurassic Sequencementioning

confidence: 99%

“…2) may illustrate the time and space relationships in the Western High Atlas during the Late Triassic up into the Early Cretaceous. Data compiled in these sections were apart from own results of recent field work taken from M~CI-IARD (1976), ADAMS et al (1980), AMBROC6~ (1963, BECKER (1987), B~RON (1983), BROWN (1980), DV DRESNAY (1971, DUFFAUD et al (1966), FROrrZI-IEW[ (1987), JENNY et al (1981), MOREa" (1931, SCHU~HN6 (1990), STJ~TS & WVRSTER (1981) and WVRSTER & STETS (1982).…”

Section: Time and Space Relationshipsmentioning

confidence: 99%

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Mid-Jurassic events in the Western High Atlas (Morocco)

Stets

1992

Geol Rundsch

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ZusammenfassungBei Kartierarbeiten und Profilaufnahmen im Westlichen Hohen Atlas in Marokko beobachtete Winkeldiskordanzen, Schichtlticken und progressive M~ichtigkeitsentwicklungen deuten auf mitteljurassische tektonische Aktivit~iten hin. Untersttitzung erh~lt diese Hypothese durch Rotsedimente des Dogger im Ktistenbecken yon Agadir-Essaouira, die hier im Gegensatz zur allgemeinen Meeresspiegelentwicklung zum Absatz kamen.In der tektonischen Entwicklung ergibt sich ein Rift-Stadium yon Perm bis Unterjura, das yon einero Golf-Stadium von Oberjura bis Mittelkreide abgel6st wird, bevor sich durch Inversion in der Oberkreide und seit dem Jungterti~ir das heutige Hochgebirge bildete. Im Mesozoikum wird Zerrungstektonik fiberlagert durch vom Atlantik ausgehende Vertikaltektonik. Sie ffihrte bereits im Mittleren Jura zu einem NNE-SSW verlaufenden Hochgebiet, das auch im heutigen >>massif ancien<< des Westlichen Hohen Atlas gipfelt und die Aufkl~irung der sedimentfiren Vorgeschichte des Gebirges erheblich erschwert. AbstractAngular unconformities, time gaps, and progressive increase of thickness in the Mesozoic sedimentary pile of the Western High Atlas, Morocco, point to mid-Jurassic tectonic pulses in this area. Red beds, Middle Jurassic in age, were deposited in the nearshore Agadir-Essaouira basin in contrast to transgressive tendencies of the eustatic curve. These phenomena are easily explained by uplift and erosion in the central part of the mountain belt even in the Middle Jurassic. Thus, a rift stage (Permian to Early Jurassic) in the tectonic history of the Western High Atlas was followed by a gulf stage (Late Jurassic to Middle Cretaceous) until later the high mountain range generated by inversion in Late Cretaceous and Neogene to recent times. Tensional forces that created the mobile rift belt were superimposed by vertical uplift during the Middle Jurassic that gave rise to a NNE-SSW stretching high. Even in the present-day high mountain range this area, called the >>ancient massif<<, is strongly elevated. Thus, the evaluation of the geological history of the Western High Atlas seems much complicated. R6sum6Dans les couches mdsozoiques du Haut Atlas occidental (Maroc), des discordances angulaires, des lacunes stratigraphiques ainsi que des variations progressives d'dpaisseur, tdmoignent d'activit6s tectoniques au Jurassique moyen. C'est ainsi qu'au Dogger, des couches rouges se sont ddpos6es dans le bassin c6tier dAgadir-Essaouira en opposition avec les tendances transgressives g6n6rales de la courbe eustatique. Ces ph4nom6nes s'expliquent facilement par des processus de soul~vement et d'drosion dans la partie centrale de la zone mobile atlasique au Jurassique moyen.Fhistoire tectonique a comport4 une p4riode de rifting (du Permien au Jurassique inf6rieur) suivie par une p6riode o6 le golfe marin atlasique s'est constitu4 (du Jurassique supdrieur au Les forces d'extension, responsables de la naissance de la zone mobile du rift atlasique, ont dtd suivies au Jurassique moyen par un soul~vement vertical en rela...

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“…6, 6). In the Southern Subatlas Zone near Telouat (SCHILLING, 1990) and farther to the North at Jb el Igoudlane (JENNY et al, 1981) …”

Section: The Jurassic Sequencementioning

confidence: 99%

Section: Time and Space Relationshipsmentioning

confidence: 99%

Mid-Jurassic events in the Western High Atlas (Morocco)

Stets

1992

Geol Rundsch

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“…La formation de Tilougguit (Jenny et al, 1981) est représentée par des dépôts détritiques formés de grès, silts et microconglomérats brun-chocolat, organisés en chenaux métriques à base légèrement ravinante à stratification horizontale et oblique. Au sommet domine la fraction grossière constituée de grès et de micro-conglomérats qui passent progressivement à la formation sus-jacente.…”

Section: Lithostratigraphieunclassified

“…La formation de Guettioua (Jenny et al, 1981) affleure dans le synclinale de Msemrir. Elle est formée par des mégachenaux hétérométriques de conglomérats, grès, silts et argiles rouges organisés en lentilles contenant des ossements de vertébrés et du bois fossile.…”

Section: Lithostratigraphieunclassified

Tectono-sedimentary events during Lias-Dogger at the southern margin of the Central High-Atlas, Morocco

Ettaki¹,

Ibouh²,

Chellaı̈³

2007

Estud. geol.

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RÉSUMÉL'analyse tectono-sédimentaire des séries du Lias et du Dogger de la marge méridionale du HautAtlas central, en particulier la région du Todrha-Dadès, montre l'existence d'une relation étroite entre la tectonique et la sédimentation. ABSTRACTThe tectono-sedimentary analysis of the Jurassic sediments in the southern margin of the central High-Atlas and particularly in the Todrha-Dadès area shows the existence of a good relationship between the tectonic and the sedimentary events. The structuring of this area is controlled by a group of faults whose cartographic axes show bending paces of direction NE-SW straightening toward the NNE. The analysis of the spatial organisation of lower and middle Lias deposits shows a dominance of carbonated deposits with ammonites, algae and foraminifera, with variations of thickness and lateral facies variations. The upper Lias and the Dogger correspond to clastic deposits and carbonates interbeded with neritic fauna. The structural analysis shows that the sedimentation in the southern margin of the central HighAtlas is controlled, in addition to eustatic factors, by a paleostress field dominated by minimum main stress fields of orientations which change depending on the age. The analysis of structures and their geometry as well as the syn-sedimentary tectonics allowed to establish the directions of the tectonic stress, which controlled the structuration of the studied basin in the Jurassic. The general synthesis of the data shows variations of distensive directions in time and space. In the Sinemurian-lower Carixian the direction of the tectonic stress (σ 3 ) is NW-SE. The middle Domerian was a relative quiet tectonic time. In the upper Domerian the distensive tectonic stress is NNW-SSE to NW-SE. In the Toarcian, the sedimentation takes place in a transtensif tectonic context. The synsedimentary structures are developed by fossilized normal faults, slope deposits and spatio-temporal variations of the facies and thickness. Geodynamic and paleo-1 Faculté Polydisciplinaire -Khouribga, département des Sciences de la Terre, B. P : 145, Khouribga principale 25000, Maroc.

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“…On the main part of the Moroccan Atlasic domain, continental red beds were deposited since the Middle Jurassic to the Upper Cretaceous (du Dresnay, 1956;Faure-Muret, 1960-1962;Jenny et al, 1981;Michard et al, 2008). Their age has been highly debated because of the lack of undisputable chronostratigraphic markers.…”

Section: Introductionmentioning

confidence: 99%

Guelb el Ahmar (Bathonian, Anoual Syncline, eastern Morocco): First continental flora and fauna including mammals from the Middle Jurassic of Africa

et al. 2016

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We report the discovery in Mesozoic continental "red beds" of Anoual Syncline, Morocco, of the new Guelb el Ahmar (GEA) fossiliferous sites in the Bathonian Anoual Formation. They produced one of the richest continental biotic assemblages from the Jurassic of Gondwana, including plants, invertebrates and vertebrates. Both the sedimentological facies and the biotic assemblage indicate a lacustrine depositional environment. The flora is represented by tree trunks (three families), pollen (13 species, five major clades) and charophytes. It suggests local forests and humid (non-arid) conditions. The vertebrate fauna is dominated by microvertebrates recovered by screening-washing. It is rich and diverse, with at least 29 species of all major groups (osteichthyans, lissamphibians, chelonians, diapsids, mammals), except chondrichthyans. It includes the first mammals discovered in the Middle Jurassic of Arabo-Africa. The GEA sites yielded some of the earliest known representatives of osteoglossiform fishes, albanerpetontid and caudate amphibians, squamates (scincomorphans, anguimorphan), cladotherian mammals, and likely choristoderes. The choristoderes, if confirmed, are the first found in Gondwana, the albanerpetontid and caudatan amphibians are among the very few known in Gondwana, and the anguimorph lizard is the first known from the Mesozoic of Gondwana. Mammals (Amphitheriida, cf. Dryolestida) remain poorly known, but are the earliest cladotherians known in Gondwana. The GEA biotic assemblage is characterized by the presence of Pangean and Laurasian (especially European) taxa, and quasi absence of Gondwanan taxa. The paleobiogeographical analysis suggests either a major fossil bias in Gondwana during the Middle Jurassic, and an overall vicariant Pangean context for the GEA assemblage, or alternatively, noticeable Laurasian (European) affinities and North-South dispersals. The close resemblance between the Bathonian faunas of GEA and Britain is remarkable, even in a Pangean context. The similarity between the local Anoual Syncline Guelb el Ahmar and Ksar Metlili faunas raises questions on the ?Berriasian age of the latter.

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Les couches rouges du Jurassique moyen du Haut Atlas central (Maroc); Correlations lithostratigraphiques, elements de datations et cadre tectono-sedimentaire

Cited by 74 publications

References 0 publications

Mid-Jurassic events in the Western High Atlas (Morocco)

Mid-Jurassic events in the Western High Atlas (Morocco)

Tectono-sedimentary events during Lias-Dogger at the southern margin of the Central High-Atlas, Morocco

Guelb el Ahmar (Bathonian, Anoual Syncline, eastern Morocco): First continental flora and fauna including mammals from the Middle Jurassic of Africa

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