What Were Some Major Geologic Events in the Triassic Period?

The Triassic Period is characterized by two main geologic events. The first was the creation and subsequent rifting of the supercontinent Pangaea. The second was the evolution of dinosaurs and mammals.

At the beginning of the Triassic Period, the continents came together to form one large supercontinent called Pangaea. Pangaea was C-shaped and located on the equator. During this time, there were no ice caps at the north or south poles, causing a hot, dry climate. By the end of the Triassic Period, Pangaea began to rift and separate into two landmasses: Gondwana and Laurasia.

By the middle to late Triassic Period, dinosaurs and mammals evolved. Large reptiles called Therapsids were dominant during this period, and they were eventually replaced by Archosaurs. Archosaurs evolved to become bipedal, marking the beginning of dinosaurs. Aquatic reptiles and small, bird-like reptiles were also present.

The first observation of mammals occurred in the late Triassic Period. The Eozostrodon, a shrew-like mammal, was approximately 3 feet long. There is still much that is unknown about early mammals, but it is evident they had fur and three ear bones, and produced milk to feed their young. The Triassic Period ends with the Triassic-Jurassic mass extinction that widely affected ocean life and ushered in the dinosaur-dominated Jurassic era.