Calcaires du Bou Dahar

The Calcaires du Bou Dahar (also known as Djebel Bou Dahar Paleoshoal, Djebel Bou Dahar, Calcaires du Bou Dahar Formation, or Bou Dahar Formation) is a geological formation or a sequence of formations of Late Sinemurian to Pliensbachian-Toarcian boundary (Early Jurassic) age in Bni Tadjite, the Central High Atlas, Morocco. This unit represents an excepcional record of an evolving reef complex (mountain laterals), platform slopes (Steep slopes between 20° and 35° on various sides) and a emerged shoal (nearly horizontal limestone layers on the top flat Bou Dahar plateau) developed inside a carbonate platform, recording the evolutionary cycles of this environment with notorious precision, also yielding what is considered one of the greatest/most diverse marine biotas of the entire Jurassic Tethys Ocean. The Bou Dahar carbonate platform shoal stands prominently and structurally above surrounding plains, spanning 35-40 km in length and 4-15 km in width, with a relief of 100-450 m. This carbonate formation originated on metamorphosed Silurian to Ordovician siliciclastic rocks and tholeiitic volcanic layers tied to Central Atlantic Magmatic Province basalts, forming a corridor oriented WSW to ENE. Surrounding alluvial plains expose green marls, shales, and dark lime-mudstones representing basinal deposits contemporaneous or subsequent to the platform. It has been considered to be a sequence of different coeval inner geological formations, including the Foum Zidet Formation, the Aganane Formation and Ouchbis Formation, but is usually interpreted as a single major unit due to it´s unique preservation.