Neoproterozoic granitoids along the Ailao Shan-Red River belt: Zircon U-Pb geochronology, Hf isotope analysis and tectonic implications

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

“…Besides the Neoproterozoic granites in the Yao Shan complex, there are many Neoproterozoic granitic intrusions reported from the other three massifs along the ASRRB (Figure ). Their ages range from 799 to 724 Ma with negative Hf values and T DMC ages of 2335.9 to 1632.2 Ma (Chen et al, ), which implies derivation of parental magmas from ancient lower crust sources. Geochemical analyses revealed that they were attributed to arc magmatism due to oceanic subduction (Chen et al, ).…”

“…Their ages range from 799 to 724 Ma with negative Hf values and T DMC ages of 2335.9 to 1632.2 Ma (Chen et al, ), which implies derivation of parental magmas from ancient lower crust sources. Geochemical analyses revealed that they were attributed to arc magmatism due to oceanic subduction (Chen et al, ). The occurrence of the Neoproterozoic granites along the ASRRB provides profound argument for the remobilization of ancient lower crust along the southwestern margin of the South China plate.…”

“…The occurrence of the Neoproterozoic granites along the ASRRB provides profound argument for the remobilization of ancient lower crust along the southwestern margin of the South China plate. Generation of crustal magmas is attributed to subduction of an oceanic plate beneath the plate (Figures a and a, Chen et al, ).…”

“…The South China plate or craton possesses Pre‐Neoproterozoic metamorphic basement that is unconformably overlain by Neoproterozoic to Paleozoic sediments (Tang et al, ). Neoproterozoic magmatic rocks, including contemporaneous granitic and mafic rocks, are widely developed along the margins of the South China plate, especially along its northern and western margins (Cai et al, ; Chen et al, ; Qi et al, , , ). The Qin‐Hang structural belt is a large‐scale suture zone, recording the process of oceanic subduction and continental collision between the Yangtze and Cathaysia blocks in early Neoproterozoic (Zheng et al, ).…”

“…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.…”