Cenomanian

The Cenomanian is a stage in the geologic timescale, specifically within the Late Cretaceous epoch. It is the third and final stage of the Upper Cretaceous series, following the Turonian and preceding the Santonian. The Cenomanian stage spans approximately 6 million years, from about 99 million to 93 million years ago. It is characterized by a period of significant environmental changes, including a global warming event known as the Cenomanian Thermal Maximum, which occurred around 93 million years ago. This event led to a rise in sea levels and a shift in marine ecosystems.

During the Cenomanian, the continents were in a configuration known as Gondwana, with Laurasia in the northern hemisphere. The climate was generally warm and humid, with a high concentration of carbon dioxide in the atmosphere. This contributed to the global warming event and the subsequent changes in marine life. Fossil evidence from this period includes a diverse array of marine organisms, such as ammonites, belemnites, and bivalves, as well as the first appearance of modern birds and the extinction of many dinosaur groups.

The Cenomanian stage is of particular interest to paleontologists and geologists due to the significant changes in the Earth's environment and the evolution of life during this time. The stage is named after the village of Cenoman in Normandy, France, where the first rocks of this age were identified. The Cenomanian is followed by the Santonian stage, marking the transition into the Late Cretaceous and the eventual mass extinction event that led to the end of the Cretaceous Period.