Triassic correlation of the Southeast Asian mainland

The Triassic in Southeast Asia is represented mainly by marine sediments. From many areas these sediments furnish abundant fossil collections, composed mostly of bivalves and ammonoids. Based on those groups, biostratigraphic scales have been compiled to make possible the correlation of the Triassic sequences of different Southeast Asian areas. Twelve assemblage zones have been distinguished, among them four are Lower Triassic, four are Middle Triassic and four are Upper Triassic. Triassic faunas from Southeast Asia have many species in common with analogous assemblages from south China and the Himalayas.