Tectonic Roles of Sediment Transport and Deposition in the Northern Andaman Sea and Eastern Bay of Bengal
Studies of the long-term geological tectonic history and recent uplift and subsidence of the Ayeyarwady Delta show: 1) Uplift induced by the oblique subduction of the Indian plate beneath the overriding southeast Asian plate has led to subsidence in the back-arc basin and created a 130-m-deep, 100-km-wide Martaban Depression. Extension created by the Andaman spreading center in the south has allowed for increased accommodation space within the depression where a 60-m-thick mud wedge has accumulated. 2) Conversely, uplift off the river mouth has led to shoaling and strong wave resuspension; therefore, sediment deposition adjacent the shelf is negligible. Instead, sediment is either diverted towards the Gulf of Martaban or along the western Myanmar coastline. 3) In the eastern Bay of Bengal, the subduction created deep sea trench may also receive sediment that has escaped from the western Myanmar shelf.