Jurassic System

The Jurassic System refers to the rock strata formed during the Jurassic Period, which spanned from 201.3 to 145 million years ago. This period, the second of the Mesozoic Era, followed the Triassic and preceded the Cretaceous. The Jurassic System is divided into three epochs: Early, Middle, and Late Jurassic, each with distinct stages often identified using index fossils like ammonites and bivalves.12

During the Jurassic, the supercontinent Pangea began to break apart, leading to significant geological changes, including the formation of the Atlantic Ocean and increased volcanic activity. On land, dinosaurs were the dominant animals, and the earliest birds appeared. Marine life was diverse, with abundant mollusks and coral reefs, alongside extinct marine reptiles and squid-like creatures. Rock formations from this period, such as the Morrison Formation in the United States and the Solnhofen Limestone in Germany, are renowned for their exceptionally preserved fossils.23