LATE PALEOZOIC AND MESOZOIC PALEOGEOGRAPHY OF SOUTHEAST-ASIA

Southeast Asia comprises a complex assemblage of allochthonous terranes derived directly or indirectly from Gondwana Land and assembled between the Late Palaeozoic and Cenozoic. The continental ''core'' of the region is made up of four principal continental blocks, South China, Indochina, Sibumasu and East Malaya. South China, Indochina and East Malaya were rifted from northeast Gondwanaland during the Silurian or Devonian and amalgamated to each other during the early Carboniferous. Sibumasu remained attached to northwest Australian Gondwana land until the late early Permian when it rifted away as part of the elongate Cimmerian continent. Collision between Sibumasu and Indochina-East Malaya probably occurred in the early Triassic forming the continental core of Southeast Asia. Other small terranes including Mount Victoria Land, Sikuleh, Natal, Semitau and southwest Borneo were accreted to this core during the Jurassic and Cretaceous to form ''Sundaland''. A series of palaeogeographic maps are presented showing interpreted palaeopositions of the various Southeast Asian terranes in the Late Palaeozoic and Mesozoic which are consistent with the current geological and geophysical constraints.