Azilal Formation

Azilal Formation
Stratigraphic range: Toarcian-Middle Aalenian 182–172 Ma Polymorphum-Murchisonae
Profile near Ikhf n'Ighir, showing the Aganane Formation in the lower Portion, and the Azilal formation in the upper
TypeGeological formation
Unit ofTafraout Group
Underlies
Overlies
AreaHigh Atlas[1][2]
Thickness300-800 m[3]
Lithology
PrimaryArgillite, conglomerate (+quartz-dredge conglomerates)
OtherBrown-red marl, siltstones (micro-sandstones), sandstone-pelitic, breccias with liasic limestone elements, lagoonal shale, sandstone and volcanic minerals.[3]
Location
LocationAzilal Province
Coordinates31°18′N 6°36′W / 31.3°N 6.6°W / 31.3; -6.6
Approximate paleocoordinates26°36′N 3°24′W / 26.6°N 3.4°W / 26.6; -3.4
RegionHigh Atlas[4][5]
Country Morocco
Type section
Named forAzilal
Named by
  • Jenny et al. (Informally)[3][6][7]
  • Milhi (Formally)
LocationNorthwest side of Jbel Mesgounane, 10 kilometers east of Azilal
Year defined
  • 1985 (Informally)[1]
  • 1992 (Formally)
Thickness at type section~250 m (820 ft)
Azilal Formation is located in Morocco
Azilal Formation
Azilal Formation (Morocco)

The Azilal Formation, also known as Toundoute Continental Series and Wazzant Formation (Called Informally "Marnes chocolat"), is a geological unit in the Azilal, Béni-Mellal, Imilchil, Zaouiat Ahansal, Ouarzazate, Tinerhir and Errachidia areas of the High Atlas of Morocco, part of the Tafraout Group that covers the Early Toarcian to Middle Aalenian stages of the Jurassic Period.[8] While there have been atributions of it´s lowermost layers to the Latest Pliensbachian, the current oldest properly measured are part of the Earliest Toarcian regresion ("MRST10"), part of the Lower-Middle Palymorphum biozone.[8] The Azilal Formation consists mainly of claystones rich in continental plant debris and laminated microbial facies.[9] It is a continental deposit which overlies marine dolomites of equivalent age to the Rotzo Formation of Italy, mostly part of the Aganane Formation.[6] The formation is the continental part of a massive Siliciclastic-Carbonate platform ("Tafraout Platform"), best assigned to an alluvial environment occasionally interrupted by shallow marine incursions (tidal flat setting) and marks a dramatic decrease of the carbonate productivity under increasing terrigenous sedimentation.[10] Dinosaur remains, such the sauropod Tazoudasaurus and the basal ceratosaur Berberosaurus are known from the unit, along with several undescribed genera.[11] The toarcian High Atlas is divided in 5 units: the continental layers with paralic deposits belong to the Azilal, along the shoreface layers of the Tagoudite Formation, Tafraout Formation & Aguerd-nˈTazoult Formation, connected with the offshore Ait Athmane Formation and the deeper shelf deposits of the Agoudim 1 Formation.[12]

  1. ^ a b Jenny, J. (1985). "Carte Géologique du Maroc au 1: 100.000, feuille Azilal". Notes et Mémoires du Service Géologique du Maroc. 339 (2): 1–104. Retrieved 25 January 2022.
  2. ^ Jenny, J. (1988). "Carte géologique du Maroc au 1/100 000: feuille Azilal (Haut Atlas central). Mémoire explicatif". Notes et Mémoires du Service géologique. 378 (1): 1–122. Retrieved 25 January 2022.
  3. ^ a b c Le Marrec, A.; Jenny, J. (1980). "L'accident de Demnat, comportement synsedimentaire et tectonique d'un decrochement transversal du Haut-Atlas central (Maroc)". Bulletin de la Société Géologique de France. 7 (3): 421–427. Retrieved 25 January 2022.
  4. ^ Peleogeographiques, C. E. R. (2002). "Les formations lithostratigraphiques jurassiques du Haut Atlas central (Maroc) : corrélations et reconstitutions paléogéographiques". Documents des laboratoires de géologie Lyon. 156 (1): 163. Retrieved 25 January 2022.
  5. ^ El Bchari, F.; Ibouh, H.; Souhel, A.; Taj-Eddine, K.; Canérot, J.; Bouabdelli, M. (2001). "Cadre stratigraphique et étapes de structuration de la plate-forme liasique d'Aït Bou Guemmez (Haut-Atlas central, Maroc)". Revista de Geociências. 16 (3): 163–172. Retrieved 25 January 2022.
  6. ^ a b Souhel, A.; El Hariri, K.; Chafiki, D.; Canerot, J. (1998). "Stratigraphie sequentielle et evolution geodnamique du Lias (Sinemurien terminal-Toarcien moyen) de l'Atlas de Beni-Mellal (Haut Atlas central, Maroc)". Bulletin de la Société Géologique de France. 169 (4): 527–536. Retrieved 25 January 2022.
  7. ^ Jossen, J. A. (1990). "Carte géologique du Maroc au 1/100000, feuille de Zawyat Ahançal". Notes et Mém. Serv. Géol. Maroc. 1 (1): 355. Retrieved 25 April 2022.
  8. ^ a b Krencker, F.-N.; Fantasia, A.; El Ouali, M.; Kabiri, L.; Bodin, S. (2022). "The effects of strong sediment-supply variability on the sequence stratigraphic architecture: Insights from early Toarcian carbonate factory collapses". Marine and Petroleum Geology. 136: 105469. Bibcode:2022MarPG.13605469K. doi:10.1016/j.marpetgeo.2021.105469. ISSN 0264-8172.
  9. ^ Cite error: The named reference Krencker was invoked but never defined (see the help page).
  10. ^ Ettaki, M; Ouahhabi, B.; Dommergues, J. L.; Meister, C.; Chellaï, E. H. (2011). "Analyses biostratigraphiques dans le Lias de la bordure sud de la Téthys méditerranéenne: l'exemple de la frange méridionale du Haut-Atlas central (Maroc)". Bulletin de la Société Géologique de France. 182 (6): 521–532. doi:10.2113/gssgfbull.182.6.521. Retrieved 25 January 2022.
  11. ^ Haddoumi, H.; Charrière, A.; Mojon, P. O. (2010). "Stratigraphie et sédimentologie des "Couches rouges" continentales du Jurassique-Crétacé du Haut Atlas central (Maroc): implications paléogéographiques et géodynamiques". Geobios. 43 (4): 433–451. Bibcode:2010Geobi..43..433H. doi:10.1016/j.geobios.2010.01.001.
  12. ^ Stüder, M.; du Dresnay, R. (1980). "Deformations synsedimentaires en compression pendant le Lias superieur et le Dogger, au Tizi n'Irhil (Haut Atlas central de Midelt, Maroc)". Bull. Soc. Géol. Fr. 34 (3): 391–397. doi:10.2113/gssgfbull.S7-XXII.3.391. Retrieved 28 March 2022.