--> ABSTRACT: Geologic Evolution of the Thailand Andaman Sea Basins, by M. W. Andreason, J. E. St. Onge, and M. V. Filewicz; #91021 (2010)

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Geologic Evolution of the Thailand Andaman Sea Basins

ANDREASON, MARK W., JAMES E. ST. ONGE, and MARK V. FILEWICZ

The Thailand Andaman Sea has recently gained renewed exploratory interest due to recent gas discoveries offshore Myanmar and juxtaposition to the petrolific North Sumatra basin to the south. There have been only twelve exploratory wells drilled within the Thailand sector including two gas discoveries. Two back-arc basins, the Mergui and the North Sumatra basin northern extension, exist within the Thailand Andaman Sea with sedimentary thicknesses exceeding 10,500 meters. Miocene reefs and Oligocene to Miocene fluvio-deltaics and turbidites constitute the major exploratory plays.

A shallow sag basin formed between the Burman and Shan plates during the Eocene due to the northward drift of the Indian Plate. With the northward drag of the Burman Plate, the North Sumatra, Mergui, and Martaban rift basins open during the early Oligocene. Marine incursions from the south advanced throughout the Late Oligocene and large deltaic complexes formed in the Mergui basin. The Burman and Shan Plates slowly rotated clockwise during this time due to the Indian subcontinent's northward push. Tectonic quiescence, a sea-level maxima, and an explosion of reef growth characterized the Early Miocene. During the Middle Miocene, the continued northward movement of the Indian and Burman Plates caused the modern Andaman basin to open. As compressional movements intensified during the Late Miocene and Pliocene, the Barisan Mountains rose on Sumatra and the Andaman basins deepened. The North Sumatra basin southern margin down-warped as sediments poured off the rising Barisan Mountains while sediment starvation characterized the Thailand Andaman Sea. 

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.