Permo–Triassic
adjective
Geology- relating to or denoting the boundary of the Permian and Triassic periods, about 245 million years ago. Mass extinctions occurred at this time, marking the end of the Palaeozoic era.
- (as noun the Permo–Triassic or Permo–Trias) the Permian and Triassic periods together or the system of rocks deposited during them.