Systematic Revision of Archaeocyatha of Western Anti-Atlas of Morocco; Preliminary Results - Archive ouverte HAL
Communication Dans Un Congrès Année : 2022

Systematic Revision of Archaeocyatha of Western Anti-Atlas of Morocco; Preliminary Results

Résumé

Archaeocyatha are sessile, benthic Porifera, characteristic of the carbonate-shelf and reef environments of the Lower Cambrian and early Middle Cambrian. They represent the oldest calcified aspiculate sponges and the first metazoans to build bioconstructions in association with calcimicrobes. Archaeocyatha are found in all continents and regarded as a key group in biology, biostratigraphy, paleoecology and paleogeography of the early Cambrian In Morocco, the archaeocyaths are specifically distributed in the Jbilets, the High Atlas and the Anti-Atlas. Previous work carried out on this fauna is back to the beginning of the XXth century with the pioneering work of Bourcard and Le Villain (1927, 1931), Russo (1927), Roch (1927, 1930) and Neltner (1929) (see Debrenne, 2014 for references) [1]. The most recent works on Moroccan archaeocyaths were published during the second part of the XXth century by F. and M. Debrenne. Their studies were based on the fossils collected by the mapping geologists of the “Service Gé ologique du Maroc “(Debrenne, 1964) [2], private collections (Debrenne F.& M, Faure-Muret A. 1992) [3] and from some of the typical localities they revisited in 1963 and 1973. (Debrenne, 1978 [4]; Debrenne F.et M., 1995 [5]). During the field work of Asmaa El Bakhouch and Adelfattah Azizi, in the Fouanou and Issafen Synclines (western Anti-Atlas), a much-diversified archaeocyath fauna was collected from reef bioconstructions developped in the upper part of 110 m thick black oolitic limestone of the Tioute Member (Igoudine Formation = Cambrian stage 3). The Renalcis and Epihyton calcimicrobes were dominant in the reef core with accessory Archaeocyathida ; at the periphery , cups of Capsulocyathida and Ajacicyathida were mostly preserved in life position. Calcimicrobial-archaeocyaths bioherms (up to 5m in diameter) intercalated within the calcareous shale unit of the Amouslek formation have been sampled. In the Fouanou syncline, the upper shales of the Issafen formation (Cambrian stage 3 and beginning of the stage 4) contain numerous giant mound complexes (up to 600 m in diameter), hosting a great diversity of Ajacicyathida The great diversity of well-preserved specimens present in the collected material allows revision and improvement of the previous works. Results are presented in this preliminary note which includes new precisions on geographical, stratigraphical and spatio-temporal distribution of Moroccan Archaeocyatha

Domaines

Paléontologie
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Dates et versions

hal-03722679 , version 1 (13-07-2022)

Identifiants

  • HAL Id : hal-03722679 , version 1

Citer

Asmaa El Bakhouch, Adeline Kerner, Abdelfattah Azizi, Françoise Debrenne, Khadija El Hariri. Systematic Revision of Archaeocyatha of Western Anti-Atlas of Morocco; Preliminary Results. 28TH session of the Colloquium of African Geology (CAG 28), Jul 2022, Fez, Morocco. pp.70-71. ⟨hal-03722679⟩
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