|
Original Article |
Department of Petroleum Geosciences, Universiti Brunei Darussalam, Tunku Link, Bandar Seri Begawan, Brunei Darussalam (e-mail: chrissmorley@yahoo.co.uk)
The Late CretaceousPalaeogene structural and tectonic events in the northern region of Sundaland represent a poorly known, but potentially important orogenic development in SE Asia. Extensive Late Cretaceous S-type granites extending from Malaysia through Thailand to Myanmar have long been used to infer an episode of crustal thickening, an inference supported by the presence of late CretaceousEocene ophiolites in Myanmar. However, structural evidence for a well-developed associated fold and thrust belt has been lacking. Apatite and zircon fission-track studies of Thailand indicate a broad regional uplift from about 80 Ma to 40 Ma, suggesting an episode of crustal thickening, but the uplift amount is modest, and not that expected for a major fold and thrust belt. Left lateral motion on major NWSE-trending strike-slip fault zones (Mae Ping and Three Pagodas faults) in Myanmar and Thailand has been attributed to HimalayanTibetan escape tectonics. This paper demonstrates that the fault zones are considerably more complicated than just NWSE trends. They are a network of branching faults with important northsouth trends as well as NWSE trends, they form large-scale, nested strike-slip duplex structures and affect a region over 1000 km long and up to 250 km wide. This diffuse, branching network of strike-slip fault trends may represent a substantial Late CretaceousPalaeogene transpressional belt. Himalayan escape tectonics represent later increments of deformation with both Oligocene sinistral and late OligoceneRecent dextral reactivation.
Key Words: Mae Ping Indochina transpression duplexes orogeny
This article has been cited by other articles:
![]() |
G. SHI, W. CUI, S. CAO, N. JIANG, P. JIAN, D. LIU, L. MIAO, and B. CHU Ion microprobe zircon U Pb age and geochemistry of the Myanmar jadeitite Journal of the Geological Society, 2008; 165: 221 - 234. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Smith, S. Chantraprasert, C. K. Morley, and I. Cartwright Structural geometry and timing of deformation in the Chainat duplex, Thailand Geological Society, London, Special Publications, 2007; 290: 305 - 323. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. K. Morley, M. Smith, A. Carter, P. Charusiri, and S. Chantraprasert Evolution of deformation styles at a major restraining bend, constraints from cooling histories, Mae Ping fault zone, western Thailand Geological Society, London, Special Publications, 2007; 290: 325 - 349. [Abstract] [Full Text] [PDF] |
||||
![]() |
M.P. SEARLE Role of the Red River Shear zone, Yunnan and Vietnam, in the continental extrusion of SE Asia Journal of the Geological Society, 2006; 163: 1025 - 1036. [Abstract] [Full Text] [PDF] |
||||