The greater Moluccas are bounded by the Pacific and Indian oceanic plates and the greater Australian and Sunda continental crustal plates or shelves.The effect of their opposing movement is a giant counterclockwise sworl. The island arcs within this pattern are parts of subduction zones between the opposing plates. The Sorong transform left lateral fault resulted from these forces and offset remnants of the W. Irian shelf terrane at least 700 km westerly to the Sula islands. Sedimentary rocks of pre-Pliocene to Permian age occur notably in Timor and the Sula islands. In most localities they are deformed and indurated to the extent of making them economic basement. Plio-Pleistocene linear sedimentary basins follow the ''S'' trend and reach a maximum of 3,000 m in thickness in NE. Ceram and Timor. Rocks include deep water claystones, shelf and lagoonal clays, bar and beach sands, and barrier coral reefs. Oil seeps occur on Ceram, Timor, and Buton (asphalt) mostly from Plio-Pleistocene rocks. Oil is produced at Bula, Ceram, from Pleistocene bar and shoreline sands in stratigraphic traps. A recent development at Bula has established prolific production from an extremely permeable Pleistocene reef.