Cotinguiba Formation
The Cotinguiba Formation is a geologic formation of Late Cretaceous (Cenomanian to Coniacian) age in the northeastern Brazil's Sergipe-Alagoas Basin. The Formation is composed of carbonates with clastic intercalations, moreover, the two members dividing it, the Sapucari and Aracaju members, are defined by the proportion of said carbonates. It also possesses a rich macroinvertebrate fauna, of which stands out its bivalve mollucs, gastropods, ammonites, as well as equinoderms and crustaceans. Description On average, the Cotinguiba Formation had a thickness of around 200 meters, although in some sections over 1000 meters have been measured. It is formed by carbonates with clastic intercalations, and it is also divided into two members, the Aracaju and Sapucaru Members. Said members are defined by the proportions of these carbonates within them. It is 200 km long and 5–10 km wide parallel to the coast. It is mainly composed by limestone–marlstone couplets, with sandstones, coquinas and limestone breccias being included in some places. These sediments were largely produced by algae and bioeroders on a shallow-water ramp. The origin of such rocks has been related with the seasonal oscillations of phytoplankton productivity, mud content and calcium production. The Turonian laminated carbonates of the Sergipe Basin have been