Le dévonien supérieur du sahara nord-occidental (algérie) : faciès, environnements et signification géodynamique des calcaires griottes

Abbache, Abdelkader; Mehadji, Abdelkader Ouali; Crônier, Catherine; Felllah, Ahmed hamza; Allaire, Ninon; Monnet, Claude

doi:10.4267/2042/70192

Cited by 6 publications

(22 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Maïder basins to the southeast in the Algerian Sahara (Wendt et al 1984;Wendt, 1985;Abbache et al 2019). In this area, the top of the Cheffar el Ahmar Formation is a distal ramp sedimentation with green shales interbedded with nodular limestones followed by 'griotte' limestones interbedded with red shales.…”

Section: The Influence Of Palaeogeography On Trilobitesmentioning

confidence: 99%

“…At the beginning of Frasnian time, the Tafilalt Platform emerged before being flooded again (Michard et al 2008) and the Maïder Platform partly emerged (Wendt, 1985). On the northwestern margin of the Algerian Sahara, a tectono-eustatic control is reflected in differences in lateral facies and thickness in sediments accumulated on a distal platform and in basins (Abbache et al 2019). The Late Devonian period marked the most important phase of epeirorgenic movements in the Saoura, leading to an important subsidence (Benhamou et al 2004).…”

Section: C Late Devonianmentioning

confidence: 99%

“…The Late Devonian period marked the most important phase of epeirorgenic movements in the Saoura, leading to an important subsidence (Benhamou et al 2004). The Upper Devonian is characterized by alternate deposits of clay-sand and limestone, especially including 'griotte' nodular limestones with benthic and pelagic faunas, which indicates an opening to marine environments (Crônier et al 2018a;Abbache et al 2019).…”

Section: C Late Devonianmentioning

confidence: 99%

“…In this area, the top of the Cheffar el Ahmar Formation is a distal ramp sedimentation with green shales interbedded with nodular limestones followed by 'griotte' limestones interbedded with red shales. The fauna consists of ammonoids, ostracods and chitinozoans (Abbache et al 2019).…”

Section: The Influence Of Palaeogeography On Trilobitesmentioning

confidence: 99%

“…the Moroccan Anti-Atlas and the Algerian Ougarta Range. These two areas are famous for their detailed stratigraphy, their numerous faunal studies and their recognized environmental changes (Wendt et al 1984;Wendt, 1985Wendt, , 1993Wendt, , 2021aWendt & Belka, 1991;Benhamou et al 2004;Ouali Mehadji et al 2011;Abbache et al 2019;Frey et al 2019). The trilobite fauna from this North African area was first studied by Le Maître (1952) followed by numerous publications by G. Alberti (e.g.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

The influence of palaeogeography and tectonic events on trilobite distributions in Morocco and northwestern Algeria

2022

View full text Add to dashboard Cite

The effects of sea-level changes and anoxia on Devonian trilobites have been studied for a long time, but the importance of palaeogeographic and tectonic events in this key-period is still not well understood. In the Devonian Period, trilobites invaded many different marine environments and areas in North Africa where important palaeogeographic changes occurred. Distribution patterns of trilobites through time and space have been analysed using a hierarchical cluster analysis and diversity indices. Our examination of the literature suggests that trilobites were scarce during Lochkovian time before an important diversification in Pragian time. Trilobites flourished in many North African regions without there being important taxonomic differences between basins, because of free migration in relatively flat palaeo-topography and homogeneous environments. During Middle Devonian time, early Variscan tectonic movements transformed the eastern Anti-Atlas area into a basin with a platform topography. Geographical barriers such as deep basins prevented trilobite migrations. At the beginning of Eifelian time, the reduction in migration between the different regions of this area coincided with a decrease in diversity. Consequently, tectonic events played an important role in the decline of trilobites during Middle Devonian time, especially when these were combined with sea-level changes and anoxic/hypoxic events. A recovery occurred in Famennian time involving only new genera. As at the global scale, cyrtosymbolines developed in shallow seas, whereas phacopids evolved in deeper environments. The basin and platform system still hampered migrations, although sea-level variations led to episodic exchanges. The late Famennian regression reduced trilobite diversity dramatically in the study area.

show abstract

Section: The Influence Of Palaeogeography On Trilobitesmentioning

confidence: 99%

Section: C Late Devonianmentioning

confidence: 99%

Section: C Late Devonianmentioning

confidence: 99%

Section: The Influence Of Palaeogeography On Trilobitesmentioning

confidence: 99%