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?

[1] The El Mers formations are composed primarily of marls with intermittent layers of limestone and sandstone, characterized by abundant organic matter and benthic fauna.

The facies associations within the El Mers Group are organized into elementary and mesosequences, delineating the transition from prodelta to deltaic plain environments.

[1] This setting oscillated between a proximal continental shelf, marked by significant terrestrial input, and episodic marine incursions that suggest fluctuating sea levels.

[1] The shifts in facies and microfauna evolution in our study area reveal intriguing patterns, from the establishment of initial supratidal environments characterized by charophytic marls and ostracod limestones followed by a resurgence of marine conditions, evident from the reappearance of coastal facies and the diversification of ostracod faunas, indicating a significant transgressive phase during the Upper Bathonian–Lower Callovian period.