Publications

A plate tectonic model for the development of the region of SE Asia and Australasia is presented and its implications are summarised. The complexity of the present-day tectonics of the region and the observable rates of plate motions indicate that major oceans, or multiple small oceans, have closed during the Cenozoic, and that the configuration of the region has changed significantly during this time. Despite the long-term convergence there has been frequent opening of marginal basins, and extension related to strikc-slip faults resulting from partitioning of oblique Convergence at plate boundaries. Present-day plate motions, based for example on GPS measurements and seismicity, illustrate the complexity of processes but appear to have little relevance in understanding the long-term kinematic development of the region. There are threc important periods in regional development: at about 45 Ma, 25 Ma and 5 Ma. At these times plate boundaries and motions changed, probably as a result of major collision events. Indentation of Asia by India may have modified the Eurasian continent but there is little indication that India has been the driving force of tectonics in SE Asia. The movement of Australia northwards has caused rotations of SE Asia blocks and accretion of microcontincntal fragmcnts to SE Asia. Since 25 Ma the oceanic region east of Eurasia has been driven by motion of the Pacific plate. To improve our tectonic models, detail is needed which can be compiled from proprietary data, such as coastline, shelf edge, age and lithofacies information, held by c'ornpanies. Improved dating of events is required in order to identify regional events and their consequences and identify the processes that cause the effects. Few sedimentary basins in the region will fit into simple basin models because of the frequency and rapidity of changes in regional tectonics.