Middle Permian high Sr/Y monzogranites in central Inner Mongolia: reworking of the juvenile lower crust of Bainaimiao arc belt during slab break-off of the Palaeo-Asian oceanic lithosphere

Min, Liu; Lai, Shaocong; Zhang, Da; Zhu, Rixiang; Qin, Jiangfeng; Xiong, Guangqiang

doi:10.1080/00206814.2019.1579057

Cited by 7 publications

(1 citation statement)

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“…Yuan, Zhang, Xue, Lu, and Zong (2016) also suggested that the late Permian (~250 Ma) high‐Mg andesites in the Kaiyuan city were most likely to represent the onset of post‐collisional magmatism corresponding to hot asthenospheric upwelling triggered by slab break‐off. All these data point to the finish of the Palaeo‐Asian Ocean plate subduction before the Triassic (Liu et al, 2019 and references therein). Thus, southward subduction of the Palaeo‐Asian Ocean plate could not be the cause for the crust thickening and subsequent high Sr/Y magmatism in the Early‐Middle Triassic.…”

Section: Discussionmentioning

confidence: 93%

Early‐Middle Triassic high Sr/Y granites in the northern margin of the North China Craton: Petrogenesis and tectonic implications

2022

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Handling Editor: E. Bozkurt Radiometric dating results and geochemical and isotopic data obtained in this study for two granitic plutons in the northern margin of the North China Craton (NNCC) provide important information on the tectonic environment of the North China Craton (NCC) in the Early to Middle Triassic. The two plutons, Wanlongchang and Baiyanaobao, were dated being formed at 247 Ma (our previous study) and 237 Ma (this study), respectively. These two granites are characterized by low initial 87 Sr/ 86 Sr ratios (0.7055-0.7073), ε Nd (t) values (À9.9 to À15.0), and zircon ε Hf (t) values (À8.7 to À27.0), suggesting their magmas originated from ancient lower crust. Both granites display high Sr/Y ratios (most >30) and (La/Yb) N (most >30), but low Cr (8.31-40.9 ppm), Ni (3.59-13.8 ppm), MgO (0.12-1.17%) contents, and low Mg # values (26-39), which suggests that the melts that formed the two granites were derived from thickened lower crust. When elemental concentration data and compiled Sr/Y ratios in the previous works are evaluated, it is revealed that many Early-Middle Triassic felsic rocks in this region have high Sr/Y ratios characters. Combining tectonomagmatic investigations, we further proposed that the Early-Middle Triassic crustal thickening may have resulted from the collision between the NCC and the South Mongolia Terranes after the final closure of the Palaeo-Asian Ocean.

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Section: Discussionmentioning

confidence: 93%