Abstract: Gravity Delineation of the Setting and Deep Structure of Southeast Asian Sedimentary Basins

Clive Foss, Mark Parker

Southeast Asia is made up of cratonic blocks of parts of the Eurasian and Indian-Australian plates and of various small continental, island-arc, and oceanic crustal fragments. The tectonic development of the area has been dominated by two separate continental rifting episodes, one of the northwestern margin of Australia and the other of the southern margin of China. Continental fragments separated during these events have traveled large horizontal distances, and their subsequent collisions (mostly with island areas) and entrapment of intervening oceanic crust have caused a very inhomogeneous marginal accretion onto the Eurasian plate of the southwestern Philippines, Borneo, Sulawesi, and the Banda Sea. Gravity data over the relatively stable older continental areas of Sundaland and th northwest Australian shelf indicate many earlier failed rifting events. Southeast Asia has also been subjected to disruption by wrench faulting associated mostly with the continental collision of India with Asia.

Cenozoic sedimentary cover is quite widespread across southeast Asia, blanketing many of the older crustal structures. A wide range of sedimentary basins has formed in varied settings and often with different tectonic controls operative during the period of development of the individual basins, defying efforts at simple basin classification. New compilations of land, marine, and satellite-derived gravity data show how the grain of the crustal basement has controlled the location and form of these basins and reveal the complex deep crustal structure that some of the basins have.

AAPG Search and Discovery Article #90982©1994 AAPG International Conference and Exhibition, Kuala Lumpur, Malaysia, August 21-24, 1994