Jurassic Jurassic The Jurassic (; from Jura Mountains) was a geologic period and system that spanned 56 million years from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period Mya. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period was marked by the major Triassic–Jurassic extinction event. Two other extinction events occurred during the period: the Pliensbachian-Toarcian extinction in the Early Jurassic, and the Tithonian event at the end; however, neither event ranks among the "Big Five" mass extinctions. The
Lake Parime the Takutu Basin or the Takutu Formation, dates back to the late Paleozoic, roughly 250 million years ago, and the basin connected with the Atlantic via the Takutu Graben. The geologic history of the Takutu Graben is characterized by one phase of volcanic activity and three depositional phases of sedimentary rocks. Rifting (due to divergent tectonic plate movements) occurred in "a lake or delta environment" in the Late Triassic to Early Jurassic periods, between 200 million and one hundred and fifty million years ago. Starting around 66,000 years ago, sea level rise and more humid conditions created flooded zones north