Cretaceous–Paleogene extinction event Cretaceous–Paleogene extinction event The Cretaceous–Paleogene (K–Pg) extinction event, also known as the Cretaceous–Tertiary (K–T) extinction, was a sudden mass extinction of some three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the exception of some ectothermic species such as the leatherback sea turtle and crocodiles, no tetrapods weighing more than survived. It marked the end of the Cretaceous period and with it, the entire Mesozoic Era, opening the Cenozoic Era that continues today. In the geologic record, the K–Pg event is marked by a thin layer of sediment called the K–Pg boundary, which can
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.