Zircon U–Pb ages, Hf isotope data, and tectonic implications of Early–Middle Triassic granitoids in the Ailaoshan high-grade metamorphic belt of Southeast Tibet

Multistage Remobilization of the Southwestern Margin of the South China Plate: Insights From Zircon U‐Pb Geochronology and Hf Isotope of Granitic Rocks From the Yao Shan Complex, Southeastern Tibet Plateau

“…Passive margin rifting is another important phase of remobilization of the southwestern margin of the South China plate, although not much evidence is preserved in the Yao Shan complex. Paleo‐Tethyan tectonics profoundly affected the Sangjiang‐Southeast Asian Tethyan domain, which is evidenced by the existence of the Changning‐Menglian, JAS and other suture zones, and related magmatic activities and deformation features (Faure et al, ; J. L. Liu et al, ; Metcalfe, , ; W. B. Wu et al, ). Widely exposed arc‐type Permo‐Triassic granitic and volcanic rocks to the west of the JAS suture zone are suggestive of westward subduction of the JAS oceanic plate beneath the Indochina plate.…”

“…Paleogeographic reconstruction showing the tectonic evolution of the Ailao Shan‐Red River belt and contiguous tectonic units at four main stages, (a) Neoproterozoic, (b) Paleo‐Tethys, (c) Late Cretaceous, and (d) Oligocene‐Miocene (modified after Chen et al, ; Metcalfe, ; Morley, ; W. B. Wu et al, ). ALS = Ailao Shan; ASRRSZ = Ailao Shan‐Red River shear zone; GZ‐LT‐ALS‐SD rift = Ganzi‐Litang‐Ailao Shan‐Song Da rift; IC = Indochina; JAS = Jinshajiang‐Ailao Shan‐Song Ma; L = Lhasa; LC‐SKT = Lincang‐Sukhothai arc; N = Nam Co; NC = North China; NQT = North Qiangtang; SQT = South Qiangtang; SC = South China; SI = Sibumasu; SU = Sundaland; T = Tarim; WB = West Burma; ZZ = Zhongzan.…”

“…Sketch maps showing plate interactions at (a) Neoproterozoic stage, (b) Paleo‐Tethys (Permo‐Triassic), (c) Late Cretaceous, and (d) Oligo‐Miocene stages (modified after Chen et al, ; J. L. Liu et al, ; W. B. Wu et al, ). (a) Subduction of oceanic plate beneath the South China plate forming the Neoproterozoic magmatic belt along the ASRRB.…”

“…In addition, another important suture zone, the Jinshajiang‐Ailao Shan‐Song Ma (JAS) suture zone, was also developed along the eastern margin of the Tethys domain (Figure ). The suture zone is suggested to be the relics of a subsidiary Paleo‐Tethys ocean from Early Carboniferous to Middle‐Late Triassic that closed due to the collision of Indochina and South China plates (Jian et al, ; Metcalfe, , ; W. B. Wu et al, ). Besides, there are two other suture zones in the northwestern part of the fan‐shaped area, that is, the western Kalaymyo and Myitkyina suture zones (Figure ).…”

“…Since the assembling of the Rodinia supercontinent in Neoproterozoic, the South China plate, especially along its margins, experienced evident magmatic activities owing to multistage oceanic subductions and intraplate tectonic activities. These include Neoproterozoic oceanic subduction from surrounding the block, and closure of the Qinling ocean to the north and the Jinshajiang‐Ailao Shan‐Song Ma ocean to the southwest during Paleo‐Tethyan evolution (Chen et al, ; Qi et al, ; W. B. Wu et al, ). Subsequently, flat‐slab subduction from the east initiated at circa 250 Ma (Z. X. Li & Li, ) and lasted for about 100 Ma, Paleo‐Pacific subduction in Cretaceous, and extrusion of the Sundaland block during the India‐Eurasian plate collision in Cenozoic had profound effects on the South China plate and part of its west neighbor‐the Sanjiang‐Southeast Asia Tethys domain.…”