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
Gangdese batholith Gangdese batholith The Gangdese batholith or Gangdese volcanic arc is a major geological structure in the south of the Lhasa terrane in Tibet, to the north of the Himalayas. The batholith formed around 100 million years ago, and was volcanically active for about 20 million years. It reactivated around 65 million years ago as the Indian plate approached Eurasia, and was active for another 20 million years. The Lhasa terrane moved northward and collided with the Qiangtang terrane along the Bangong-Nujiang suture towards the end of the late Jurassic (). Collision activity continued until the early Late Cretaceous () Ma.