Permian-Triassic Boundary in middle and eastern Tethys

The recent investigation on the conformable Permian-Triassic transition beds in South China revealed the existence of the mixed-fauna beds immediately above the Changhsing Formation or its equivalent, which contain the Permian-type brachiopods and the Triassic-type ammonoids and bivalves. Three successive mixed-fauna beds, numbered 1 to 3, can be distinguished at many places. The first two are referred as the Otoceras Zone and the last one as the Ophiceras Zone based on the new discovery of Otoceras sp. from the mixed-fauna bed no. 1 and a common occurrence of Ophiceras and Claraia in bed no. 3. The correlation of the Chinese sections with Permian-Triassic sequences in other parts of the Tethys province, such as Iran, Pakistan, and India, shows some time gap between the Upper Permian and Lower Triassic in those regions with the exception of Kashmir region. The Chinese sequences contain abundant ammonoids, brachiopods and conodonts that are useful for international correlation. Thus, the Chinese section, especially of the Changxing area, is considered to be a candidate of the stratotype of the Upper Permian and the Permian-Triassic boundary.