Cretaceous Cretaceous The Cretaceous (, ) is a geologic period and system that spans 79 million years from the end of the Jurassic Period million years ago (mya) to the beginning of the Paleogene Period mya. It is the last period of the Mesozoic Era, and the longest period of the Phanerozoic Eon. The Cretaceous Period is usually abbreviated K, for its German translation "Kreide" (chalk, "creta" in Latin). The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now-extinct marine reptiles,
Late Triassic the impact of an asteroid, climate change, or rising sea levels. The Carnian Age is the first stage of the three to occur during the duration of the mass extinction era. The Carnian age developed about 228 to 217 million years ago, and signals the start of the Late Triassic Epoch. The Carnian stage can further be broken down to relative species activity during the time, based on fossils and evidence found dating back to this time period. For example, marine life such as "serenites nanseni" and "Trachyceras Obesum" can be dated back to the early Carnian stage. Meanwhile, "Tropites