A reconstruction of the last 50 My of South-East Asia's tectonic history

We present 2-D reconstructions representing the extended version of the continental extrusion model, on which late Paul Tapponnier worked with the co-authors, and which provides a coherent mechanism for the origin of most major faults and basins in South-East Asia, in the last 50 My. In that model, the northward progression of India within Asia induces the nucleation and motion along a series of major strike-slip faults allowing the extrusion to the southeast of slices of Sundaland. Along the faults, and at their tips, pull-apart basins form, corresponding to the basins around Sundaland. A first NNE trending right-lateral fault opens the Mergui basin. From ~42 until 32 Ma, five NW-SE left-lateral faults activate from SW to NE extruding blocks toward the SE, allowing the formation of the Pattani, Malay, Tonle Sap, Yinggehai, and Natuna-Rajang pull-apart Basins, and terminating in the Makassar, Nam Con Son, Cuu Long Basins and the South China Sea. The faults are the Three Pagodas, Wang Chao, Tonle Sap, and the Ailao Shan / Red River shear zones. After ~15 Ma extrusion stops in Sundaland and migrates further north. A major tectonic reorganization follows on land with offshore inversion of motion of several microplates, initiating a thrust of Borneo over the southern margin of the South China Sea, forming a sedimentary prism often misinterpreted as evidence for subduction of a proto-South China Sea. We discuss how the motion on strike-slip faults resulting from India-Asia collision explains most of the rifting and seafloor spreading in the region. • A simple though very elaborated 2-D model of deformation of Southeast Asia is presented with 1 My step animation. • The extrusion model of deformation of Southeast Asia accounts for most major Cenozoic strike-slip fault and basin formation in the last 50 My. • The indentation of India into Eurasia since 55 Ma has been the driving force for most of the deformation of Southeast Asia.