Formation and Evolution of the Andaman Sea, South East Asia.
IPGP - Îlot Cuvier
Soutenances de thèses
Géosciences marines (LGM)
The Andaman Sea is an enigmatic feature hosting an active spreading center between the Malaya Peninsula in the east and the arc-shape Andaman-Nicobar forearc islands in the west, a part of the Sunda subduction that ruptured during the 2004 great earthquake. The present day spreading in the Andaman Sea started ? 4.5 Ma ago, resulting from a combination back-arc extension and pull-apart along the right-lateral strike-slip faults, the Great Sumatra Fault in the south and the Sagaing Fault in Myanmar, resulting from the slip-partitioning of the oblique convergence of the Indian Plate beneath the Sunda plate, leading to the formation of the Burmese sliver plate. As the boundary between the Burmese sliver plate and the Sunda plate lies in the Andaman Sea, it remained poorly understood. As the Andaman Sea is surrounded by continents, a significant portion of the plate boundary, including the active spreading center, is covered by thick sediments recording the evolutionary history of the Andaman Sea. In this thesis I use a set of seismic reflection profiles (? 7 000 km) provided by Petroleum GeoServices (PGS) added to bathymetry and relocated seismicity data, to first provide insight on the crustal accretion processes at sedimented spreading centers (interactions between sediments, magma emplacement and faulting), and then use the information on the 4.5 Ma evolution of the Andaman Sea to provide constraints on the nearby faults and show how the Andaman Sea is embedded in a more general geological context of a slip-partitioning in the region.