El Mers Group
| El Mers Group | |
|---|---|
| Stratigraphic range: Bajocian-Callovian ~ | |
| Type | Group |
| Sub-units | El Mers Formations 1–3 |
| Underlies | Unconformity with Barremian or Plio-Pleistocene sediments |
| Overlies | Ich Timellaline–Bou Akrabene Formation |
| Thickness | Over 500 m (1,600 ft) |
| Lithology | |
| Primary | Marl, gypsum (only in unit 3) |
| Other | Sandstone, limestone |
| Location | |
| Coordinates | 33°30′N 4°18′W / 33.5°N 4.3°W |
| Approximate paleocoordinates | 28°18′N 2°00′W / 28.3°N 2.0°W |
| Region | Boulemane and Azilal Provinces |
| Country | Morocco |
| Extent | Middle Atlas |
The El Mers Group is a geological group in the Middle Atlas of Morocco. It is subdivided into three formations named the El Mers I, II, and III Formations, respectively. It is a marine deposit primarily consisting of marl, with gypsum present in the upper part of unit 3. It is the lateral equivalent of the terrestrial Guettioua Sandstone. Dinosaur remains are among the fossils that have been recovered from the group, most notably those of sauropods and the unusual thyreophorans Adratiklit, Thyreosaurus, and Spicomellus. This formation records a series of coastal to shallow marine settings of Middle Jurassic (with an age of Bajocian-Bathonian for El Mers 1 and a Bathonian-Callovian? for El Mers II-III), based on detailed stratigraphical biomarkers such as ammonites or Foranimifera.