--> Abstract: Late Oligocene and Early Miocene Evolution of the Carbonate System in the Gulf of Martaban (Northern Andaman Sea): Comparison with the Maldives, by Dipanjan Mitra, Andre W. Droxler, Philippe Lapointe, and Arthur H. Saller; #90039 (2005)

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Late Oligocene and Early Miocene Evolution of the Carbonate System in the Gulf of Martaban (Northern Andaman Sea): Comparison with the Maldives

Dipanjan Mitra1, Andre W. Droxler1, Philippe Lapointe2, and Arthur H. Saller3
1 Rice University, Houston, TX
2 Total Exploration and Production, 64018 Pau Cedex, France
3 Unocal Corp, Sugar Land, TX

The Gulf of Martaban (GM) carbonate system, established in a back arc of the Andaman Sea and consisting of a series of short lived (late Oligocene – early Miocene), relatively thin, isolated platforms, lies today buried under a thick pile of middle Miocene or younger siliciclastics. In spite of its limited geographical extent, its active tectonic setting and evolution in proximity of large input of siliciclastics, in addition to its short lifespan, the comparison between the evolution of the GM carbonate system and the Maldives neighboring carbonate edifice, is still worthwhile.

This study is based on the interpretation of a 3D seismic cube merged into a more regional 2D seismic grid and groundtruthed by wells. Basement tectonics controlled the establishment and early evolution of two isolated carbonate platforms, separated by an intervening channel partially infilled with banktop derived sediments during the latest Oligocene. This carbonate growth phase was terminated by a lateral input of siliciclastics, filling the channel and fully covering the platform tops by a 20 m-thick layer of shale, during a well-established sea-level fall at the Oligocene-Miocene boundary. A single platform established on this smoothed relief, systematically back-stepped while aggrading during a long term early Miocene sea-level transgression. This platform drowned ~18 Ma, with a gap of several million years before being buried during the series of middle Miocene sea-level regressions. The Maldives, because of its bigger size, greater growth potential, and lack of siliciclastics, kept up with those early Miocene rates, while the GM carbonate system drowned.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005