ABSTRACT: The Tectonic Development of South-Central Asia and the Paleogeographic Setting of its Hydrocarbon Resources

Christopher R. Scotese, Willis W. Tyrell, Jr., Kevin A. Maher

The countries of south-central Asia (Afghanistan to Thailand) are made up of fragments of Gondwana that collided with the southern margin of Eurasia during the Mesozoic and Cenozoic. The Cimmerian terranes (Turkey, Iran, Afghanistan, Qiang Tang, and Burma-Malaya) rifted away from Gondwana beginning in the Late Carboniferous and were accreted to Asia during the Late Triassic-Jurassic. The Lhasa terrane, presumably also derived from Gondwana, was accreted during the Late Jurassic. By the Early Cretaceous, India-Madagascar had separated from Africa and from Australia-Antarctica. In the middle Cretaceous, India rapidly rifted away from Madagascar, and during the early Eocene collided with Asia giving rise to the Tibetam Plateau and the mountain belts from Afghanistan through urma. The sedimentary basins and petroleum provinces adjacent to and south of these collision zones are best understood when viewed in the context of their tectonic history and paleogeographic setting.

About 7 billion bbl of oil and 50 tcf of gas have been discovered in south-central Asia, mostly in Cenozoic deltaic sandstones or marine carbonate reservoirs in rift (Cambay), passive margin (Bombay shelf), and foreland basins (Assam, Indux, Potwar, Bengal) in India, Pakistan, and Bangladesh, and in a fore-arc setting in Burma. Source rocks are mostly Paleogene shale, but some Paleozoic and Mesozoic sources are present in Pakistan. New exploration is underway or will begin soon in India, Bangladesh, Nepal, and Burma.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990