La limite Cénomanien-Turonien dans le Haut Atlas central, Maroc

Ettachfini, El Mostafa; Souhel, Abdellatif; Andreu, Bernard; Caron, M.

doi:10.1016/j.geobios.2003.07.003

Cited by 52 publications

(26 citation statements)

References 6 publications

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“…The Akrabou Formation is fully marine, comprising shallowwater carbonates (mostly dolomitized) at the base, and finely-bedded carbonate mudstone at the top. This formation is similar to the CTB sections described elsewhere in the Central High Alas (ETTACHFINI et al, 2005) and the PreAfrican Trough (LÉZIN et al, 2012). The stratigraphic position of the CTB δ 13 C shift, as well as biostratigraphic data (LÉZIN et al, 2012) suggest that the basal shallow-water carbonates of the formation are latest Cenomanian, and the overlying, evenly-bedded mudstone early Turonian in age.…”

Section: Tinghir Sectionsupporting

confidence: 81%

“…Cenomanian deposits are only known on the shoulders of the two branches of the rift. In these eastern areas, the map is constructed from the works of CISZAK et al (1999) and HADDOUMI et al (2008HADDOUMI et al ( , 2010 in the Middle Atlas, of ETTACHFINI et al (2005) and LÉZIN et al (2012) on the southern border of the High-Atlas in eastern Morocco, and from BENYOUCEF et al (2014) in the Bechar area (Saharan platform, western Algeria). Stratigraphic data from CAVIN et al (2010) and satellite images are used to delineate the Kem Kem embayment.…”

Section: Palaeogeographic Contextmentioning

confidence: 99%

“…The present study deals with uppermost Albian to Cenomanian sequences, in which the relationships between marine and continental facies can be clearly deciphered from a sequence stratigraphic point of view. In the latest Cenomanian to lower Turonian a major marine flooding occurred (ETTACHFINI et al, 2005;GROSHÉNY et al, 2008GROSHÉNY et al, , 2013JATI et al, 2010;LÉZIN et al, 2012) all along the northern margin of the Saharan craton, and is responsible for the temporary disappearance of continental deposits in short-term, high-frequency sequences.…”

Section: Introductionmentioning

confidence: 99%

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Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

Essafraoui¹,

Ferry²,

Groshény³

et al. 2015

Carnets Geol.

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Seven sections, covering the upper Albian to lowermost Turonian, have been correlated from full-marine to continental-dominated deposits across a passive margin, along a transect 425 km long, from the present-day Atlantic coast to the "Pre-African Trough" between the Anti-Atlas and the HighAtlas. The thickness of the Cenomanian succession changes from around 500 metres in the fully marine sections to 250 metres in mostly continental facies in the western High-Atlas, about 150 km updip, to a few tens of metres in the Bou Tazoult area. The strata thicken again eastwards into the Pre-African Trough where they can be traced without major facies changes to the Kem Kem embayment and to the Bechar area in Algeria. Over all this eastern area, continental facies are overlain by the fully-marine shallow-water deposits of the Cenomanian-Turonian boundary interval. A first major conclusion is that fluvial aggradation in high-frequency transgressive-regressive sequences is coeval with the seaward-shift of the shoreline, in accordance with the genetic sequence stratigraphic model of GALLOWAY (1989). Both the flatness of the depositional profile and the corresponding very low energy of the marine environment during the transgressions account for the blanket of red continental clays on top of marine facies in updip depositional sequences, which is then preserved under the marine transgressive surface of the next sequence. Carnets Geol. 15 (12)A second major conclusion is that the high-frequency transgressive-regressive (T-R) sequences do not look like classical parasequences bounded by transgression surfaces. They usually exhibit a surface created by a sea-level fall within the regressive half-cycle. This is interpreted in the following way: regressions did not operate through a regular seaward-shift of the shoreline, but through stepped sealevel falls. The very low slope of the depositional ramp is thought to have enhanced the sequence stratigraphic record of such stepped regressions. Short-term, high-frequency sequences are organized into medium-frequency T-R sequences (seven in the Cenomanian) which show an overall aggrading and slowly retrograding pattern along the whole transect.Comparisons with other basins show that medium-frequency sequences do not fit the third-order depositional sequences described elsewhere, casting doubts about a eustatic mechanism for their deposition. Tazoult), sur environ 250 km. La série s'épaissit à nouveau vers l'est dans le sillon pré-africain où elle peut être suivie sans changements notables vers le golfe des Kem-Kem et le secteur de Béchar en Algérie. Sur toute la partie orientale de la transversale, les faciès continentaux ou mixtes sont recouverts par les dolomies marines du passage Cénomanien-Turonien. Une première conclusion majeure est que, dans les séquences transgression-régression (T-R) à haute fréquence, l'aggradation fluviatile accompagne sans hiatus le déplacement de la ligne de rivage au cours du demi-cycle régressif, en accord avec le modèle génétique de GALLOWAY (...

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Section: Tinghir Sectionsupporting

confidence: 81%

Section: Palaeogeographic Contextmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

Essafraoui¹,

Ferry²,

Groshény³

et al. 2015

Carnets Geol.

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“…The magmatic outcrops and associated structures from the High Atlas are described in Schaer & Persoz (1976), Monbaron (1980), Laville & Harmand (1982), Jenny (1984, Studer (1987), Brechbühler et al (1988), El Kochri & Chorowicz (1996, and Laville & Piqué (1992). For the Cretaceous marine transgressions, see , Andreu (1989), Charrière & Vila (1991), Ennslin (1992), Charrière (1996), Charrière et al (1998), Ciszak et al (1999), Ettachfini et al (2005). The paleogeography at the scale of the Maghreb in general is described in Fabre (2005).…”

Section: From the Late Jurassic Emersion To The Late Cretaceous Transmentioning

confidence: 99%

The Atlas System

Lamotte

Zizi

Missenard

et al.

Lecture Notes in Earth Sciences

124

114

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“…) and in the USA, in the Western Interior Basin (Caron et al 2006;Desmares et al 2007). In North Africa, its repercussions were also widely studied, in particular in Tunisia (Accarie et al 2000;Burollet and Robaszynski 1991;Robaszynski et al 1990Robaszynski et al , 1993aRobaszynski et al , 1993bCaron et al 1999Caron et al , 2006Zagrarni et al 2008), and to a lesser extent in Morocco (Tsikos et al 2004;Ettachfini and Andreu 2004;Ettachfini et al 2005) and in Algeria (Naili et al 1995;Groshény et al 2007). According to these various authors, the C/T crisis, which involved a major upheaval of the environment, is at the origin of the deposit of important quantity of organic carbon at the bottom of the oceans (Schlanger et al 1987;Arthur et al 1988;Jenkyns et al 1994), which appears in the form of 'black shales' layers.…”

Section: Paleoenvironmentmentioning

confidence: 99%

Micropaleontological study (foraminifera, ostracods) and characterization of the paleoenvironment of middle Cretaceous deposits (Djebel Chemla area, north-eastern Algeria)

Ruault-Djerrab

Kechid-Benkherouf

2010

Arab J Geosci

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The Djebel Chemla section is situated in the north-east of Algeria, close to the town of Tébessa and just a few kilometers from the Tunisian border. This section is composed mainly of a sequence of marl and marly limestone levels, alternating with recurring oyster levels which range in age from Vraconnian to the Early Turonian. Firstly, the micropaleontological study of the content (counting of foraminifera and ostracods, thin sections) allows the subdivision of the section into four biozones, with Rotalipora appenninica, Rotalipora globotruncanoides, Rotalipora cushmani, and Whiteinella archaeocretacea as bio-indicators; and, secondly, it provides the opportunity to specify the paleoenvironment. The supposed depositional environment is rather calm and deep, of an external platform type, with a maximum depth of 200 m. Bottom waters seem to be commonly poorly oxygenated. The end-Cenomanian anoxic crisis was also characterized by the presence of Bahloul facies levels, rich in TOC, in filaments and of globulous planktic foraminifera, including a considerable proportion of Heterohelix. The genus Rotalipora has disappeared a few levels lower down.

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La limite Cénomanien-Turonien dans le Haut Atlas central, Maroc

Cited by 52 publications

References 6 publications

Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

Sequence stratigraphic architecture of marine to fluvial deposits across a passive margin (Cenomanian, Atlantic margin, Morocco, Agadir transect)

The Atlas System

Micropaleontological study (foraminifera, ostracods) and characterization of the paleoenvironment of middle Cretaceous deposits (Djebel Chemla area, north-eastern Algeria)

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