Le Cénomanien et le Turonien de la Plate-forme Préafricaine du Maroc

Ettachfini, El Mostafa; Andreu, Bernard

doi:10.1016/j.cretres.2004.01.001

Cited by 109 publications

(107 citation statements)

References 12 publications

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“…As a result, the Kem Kem compound assemblage, as defined here, encompasses fossils from two formations: the lower Ifezouane Formation and the upper Aoufous Formation (Ettachfini and Andreu, 2004). Although most of the vertebrate remains described to date are from the lower Ifezouane Formation, the Aoufous Formation also contains a number of vertebrate records; however many occurrences from across the Kem Kem, because they lack field data, cannot be assigned to either of these formations with confidence.…”

Section: Age Palaeoenvironment and Palaeogeographymentioning

confidence: 96%

“…The hamada domain extends to the south of the High-Atlas, mainly over the Sahara craton (Zouhri et al, 2008) and belongs to the Plateforme Préafricaine (Ferrandini et al, 1985;Ettachfini and Andreu, 2004). It comprises the Imini and Goulmima narrow plateaus wedged between the Anti-Atlas and the High-Atlas and is limited to the north by the major South-Atlasic fault, the Guir Hamada in the East, the Kem Kem Plateau in the South, and the Draa Hamada in the southwest (Zouhri et al, 2008).…”

Section: Geological Settingmentioning

confidence: 99%

“…Following Ettachfini and Andreu (2004), we thus propose use of the names Ifezouane, Aoufous and Akrabou formations to classify the Cretaceous sediments in the area. We also suggest retention of the term 'Kem Kem beds' to characterise the vertebrate assemblages of both the Ifezouane and Aoufous formations as so far we have not been able to distinguish two different sets of taxa in this package of sediments.…”

Section: Geological Settingmentioning

confidence: 99%

See 2 more Smart Citations

Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

Cavin

Tong

Boudad³

et al. 2010

Journal of African Earth Sciences

186

174

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Section: Age Palaeoenvironment and Palaeogeographymentioning

confidence: 96%

Section: Geological Settingmentioning

confidence: 99%

Section: Geological Settingmentioning

confidence: 99%

See 1 more Smart Citation

Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

Cavin

Tong

Boudad³

et al. 2010

Journal of African Earth Sciences

186

174

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“…Mass accumulations of thin bivalve shells ("filaments") occur in several distinct limestone and marly intervals throughout the Mesozoic Tethyan realm [e.g., Robaszynski et al, 1994;Maamouri et al, 1994;Molina et al, 1997;Accarie et al, 2000;Abdallah et al, 2000;Wan et al, 2003;Ettachfini and Andreu, 2004;Caron et al, 2006;Zagrarni et al, 2008;Navarro et al, 2009]. Jurassic filaments are thought to represent protoconchs or juvenile shells of posidoniid bivalves (Bositra, Posidonia), while Triassic occurrences are attributed to halobiid bivalves [Lapparent, 1923;Colom, 1955;Flügel, 2004].…”

Section: Introductionmentioning

confidence: 99%

The filament event near the Cenomanian-Turonian boundary in Tunisia: filament origin and environmental signification

Negra

Zagrarni

Hanini

et al. 2011

Bulletin De La Société Géologique De France

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Abstract. -Near the Cenomanian-Turonian boundary, the filament event corresponds to the massive occurrence of thin elongate shells, probably bivalves which constitute, in the Bahloul Formation, about 40% of allochems. This biosedimentary event was described in several areas, such as in Tunisia, Algeria, Morocco, North America, Oman and Tibet. In Tunisia, filaments are well represented within well laminated black shales constituting the Bahloul Formation, late Cenomanian -early Turonian in age. These black shales were deposited under anoxic conditions developed in an outer ramp environment. Filaments are particularly abundant in the upper part of the Bahloul Formation, which is topped by a condensation level exhibiting encrusted ammonites associated with frequent burrows, and phosphatic and glauconitic grains. In terms of depositional environments, the filament concentrations announce an evolution towards "normal"-marine conditions, which followed the anoxic conditions favouring black-shale formation. This trend coincided with a deepening that led to maximum flooding at the condensation surface. The petrographic study of samples taken along a N-S transect shows a clear evolution of filament structures from distal to proximal ramp. Limestones deposited in the outer ramp environment mainly contain well preserved "pelagic" bivalve shells showing a thin-shelled structure composed of elongated filaments. Laterally, toward the proximal ramp, the bivalve shells are progressively disintegrated, the filaments being arranged parallel to bedding. In an even more proximal setting, filaments appear finer, highly fragmented and arranged without preferential orientation. The Cenomanian-Turonian "pelagic" bivalves thus probably lived in an outer ramp environment and their thin shells disintegrated progressively into filaments. This happened during high energy conditions generated by storms.The filament event, which is associated to other bio-events expressed by the extinction and the first occurrence of some pelagic species, could be used to establish local to global correlations.When the ammonite Watinoceras, the main early Turonian marker, is rare or absent, the filament-rich facies could indicate the proximity of the Cenomanian-Turonian boundary.At a global scale, the filament event illustrates a sea-level rise in relation with eustatic and climatic changes. The maximum flooding of this transgressive event was identified in several localities and dated about 93 Ma. The very high sea-level conditions are favourable to accumulation and preservation of organic-rich facies such as black shales, which illustrate the anoxic event OAE2.The abundance of filaments near the Cenomanian-Turonian boundary is an indicator of high organic productivity following a climatic change to warmer conditions. The latter have clearly influenced oceanic water-masses circulation, water column stratification and nutrient partitioning. L'événement "à filaments" à la limite Cénomanien -Turonien en Tunisie : origine et milieux de genèse des filamentsMots-c...

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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: 97%

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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Le Cénomanien et le Turonien de la Plate-forme Préafricaine du Maroc

Cited by 109 publications

References 12 publications

Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

Vertebrate assemblages from the early Late Cretaceous of southeastern Morocco: An overview

The filament event near the Cenomanian-Turonian boundary in Tunisia: filament origin and environmental signification

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

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