Azilal Formation

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, Ouarzazate, Tinerhir and Errachidia provinces of the High Atlas of Morocco, that cover the Latest Pliensbachian to Middle Aalenian stages of the Jurassic Period. It is a terrestrial deposit which overlies marine dolomites of equivalent age to the Rotzo Formation of Italy, mostly part of the Aganane Formation. Dinosaur remains, such the sauropod Tazoudasaurus and the basal ceratosaur Berberosaurus are known from the unit, along with several undescribed genera. The Units inside the group have been considered individual on the past, being a division of the so-called "Couches rouges", and subdivided by a supposed geological scale. The strata of the group extends towards the Central High Atlas, covering different anticlines, and topographic accidents along the range of the Mountains. Although new studies have suggested that the strata is coeval in age, and should be referred to as a unique unit. The formation is 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. The Azilal Formation consists mainly of claystones rich in continental plant debris and laminated microbial facies. 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 and Tafraout Formation, both connected with the offshore Ait Athmane Formation and the deeper shelf deposits of the Agoudim 1 Formation.

Azilal Formation
Stratigraphic range: Latest Pliensbachian-Middle Aalenian Spinatum-Murchisonae
Panoramic of the High Atlas on Gorges du Dadés with Toarco-Aalenian Redbeds
TypeGeological formation
Unit ofTafraout Group
Underlies
  • Azrif Formation
  • Bin el Ouidane Formation
  • Tanat Formation
Overlies
  • Aganane Formation
  • Azmerai Formation
  • Choucht Formation
  • Tagoudite Formation
  • Trafraout Formation
  • Tamadout Formation
AreaHigh Atlas
Thickness300-800 m
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.
Location
LocationAzilal Province
Coordinates31.3°N 6.6°W / 31.3; -6.6
Approximate paleocoordinates26.6°N 3.4°W / 26.6; -3.4
RegionHigh Atlas
Country Morocco
Type section
Named forAzilal
Named by
  • Jenny et al. (Informally)
  • Milhi (Formally)
LocationNorthwest side of Jbel Mesgounane, 10 kilometers east of Azilal
Year defined
  • 1985 (Informally)
  • 1992 (Formally)
Thickness at type section~250 m (820 ft)
Azilal Formation (Morocco)
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