Publications

A major difficulty in interpreting the pre-Cainozoic palaeogeography of the Indonesia-Philippine region results from the Cainozoic tectonics which have considerably altered the original distribution of the pre-Cainozoic rocks. These tectonic effects ary of two kinds, plate margin deformations and the extensional development of marginal basins with associated migration of island arcs.The remarkable similarity between the para-autochthonous and autochthonous Mesozoic facies of the Outer Banda Arc, Sula Spur and Australian NW Shelf indicate that they were on the same plate throughout the Mesozoic. These areas represent part of Australian Gondwanaland.Stratigraphical and structural analysis of eastern Indonesia reveals the presence of overthrusts composed of Permian and Mesozoic rocks that can be correlated with those of western Indonesia and the Philippines. Western Indonesian Mesozoic rocks may be related to a marginal trench and magmatic arc that characterised the northern margin of Tethys in SE Asia. This active margin extended south of the Philippines and Ryukyu Arc to Japan.Late Mesozoic extensional tectonics are thought to have initiated the development of the marginal seas of Indonesia and the Philippines. These Mesozoic extensional tectonics were associated with the migration of the island arcs towards the Tethys Ocean, a process that became more important during the Cainozoic.The Philippines appear to have migrated away from the continental margin of SW China during the Late Mesozoic extension of the South China Sea so that they formed a Mesozoic island arc on the northern margin of Tethys.The western Indonesian ",Sundaland Peninsula", appears to have developed into a mobile accretionary, shelf as a result of ",cratonisation", of the continental margin behind the oceanward migrating Sunda Arc. In contrast the ",Sula Peninsula", of eastern Indonesia, which formed part of the southern margin of Tethys and was part of Australian Gondwanaland, appears to have behaved as a passive rifted-type shelf throughout the Mesozoic.