Correlation and connection of the main suture zones in the Greater Mekong subregion

There are many suture zones in the Greater Mekong subregion. Some views about the N-S extension and connection of these suture zones have been proposed as follows on the basis of the spatio-temporal evolution and arrangement of the suture zones and other tectonic units. (1) The Indo-Burma Ranges suture zone extends northwards connecting with the Putao-Myitkyina suture zone, and then westwards connecting with the Yarlung Zangbo suture zone. (2) The Putao-Myitkyina suture zone is cut off at its southwestern end by the Sagaing dextral fault and the faulted part of the suture zone should be the Xiadusu-Nongdong zone within the northern section of the Inner-Burman central volcanic arc belt. Towards the south, the suture zone may be covered by the Paleogene and Neogene sediments. (3) The Bangong Lake-Nujiang suture zone extends southwards connecting with the Luxi-Mogok suture zone, and towards further south it may hide beneath the nappes of Mergui and Mogok Groups. (4) The Changning-Menglian suture zone extends southwards connecting the Chiang Mai suture zone, and then conjugating the Lancangjiang suture zone. The pre-existing Changning-Menglian-Chiang Mai Ocean together with Mali-Tanggar rift basin and Shuanghu-Gangmarco oceanic basin in Xizang may be aligned like a paternoster, as in the case of the present-day Sea of Japan, East China Sea Trough and South China Sea. (5) The main part of the Lancangjiang suture zone is a concealed suture zone beneath the nappes within the Dongdashan-Lincang-Kengtong granite belt. Towards the south, it connects with the Chiang Rai-Mae Tha concealed suture zone in Thailand and Bentong-Raub suture zone in the Malay Peninsula, and towards the north, it connects with the Hoh Xil-Jinshajiang suture zone in the Xijir Ulan Lake area. The Hoh Xil-Lancangjiang-Bentong-Raub suture zone is interpreted as the boundary between Gondwana and Laurasia during the Late Palaeozoic. (6) The Nan River-Uttaradit suture zone extends northwards to the Xiaohe River west of Simao, Yunnan, and then ends in the area north of it; towards the south, the suture zone connects with the Sa Kaeo and Kampot-Ha Tien suture zone. (7) The Ailaoshan-Srepok suture zone is a newly delineated suture zone, which extends from the Ailao Mountains southwards via the Nam Ou region and Dien Bien Phu mafic and ultramafic rock belt in Laos to Loei suture zone in Thailand and Srepok suture zone in Cambodia. (8) Just like the Ailaoshan suture zone, the Song Ma suture zone is a superimposed zone of the Early and Late Palaeozoic Song Ma suture zones. The Early Palaeozoic Song Ma suture zone connects westwards with the Jinshajiang-Ailaoshan suture zone, and eastwards, if the Red River left-handed fault is completely restorated, it should connect with the Chay River suture zone in northern Viet Nam, which was formed during the subduction of the South China Ocean. The Youjiang rift basin north of the Chay River suture zone can be compared with the Song Da rift basin (or small oceanic basin) in Viet Nam and Garze-Litang oceanic basin in Sichuan, China. All these basins formed a latest Late Palaeozoic-Early Palaeozoic basin belt centred by the Emei mantle plume.