Report
Evolution of the Tethyan Bangong-Nujiang Ocean and its SE Asian connection: Perspective from the Early Cretaceous high-Mg granitoids in SW China
| العنوان: | Evolution of the Tethyan Bangong-Nujiang Ocean and its SE Asian connection: Perspective from the Early Cretaceous high-Mg granitoids in SW China |
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| المؤلفون: | Ma, Peng-Fei, Xia, Xiao-Ping, Lai, Chun-Kit, Cai, Ke-Da, Cui, Ze-Xian, Xu, Jian, Zhang, Le, Yang, Qing |
| بيانات النشر: | ELSEVIER |
| سنة النشر: | 2021 |
| المجموعة: | Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) / 中国科学院广州地球化学研究所机构知识库 |
| مصطلحات موضوعية: | Geochemistry & Geophysics, Mineralogy, Early Cretaceous, Tengchong Terrane, Bangonghu-Nujiang suture, High-Mg diorite, Mafic enclave |
| الوصف: | High-Mg diorites (HMDs) have important implications on crust-mantle interactions and subduction processes, and are widely used to delineate ancient convergent plate margins. In this study, we described a newly identified high-Mg diorite-granodiorite suite in the Tengchong terrane (SE Tibetan Plateau), and presented its petrography, whole-rock geochemistry, Sr-Nd isotopes, and zircon U-Pb-Hf-O isotopic compositions. High precision SIMS zircon U-Pb dating yielded consistent Early Cretaceous ages (similar to 120 Ma) for all lithologies in this high-Mg suite. The high-Mg diorite is characterized by high MgO (4.7-9.2 wt%), Cr (169-323 ppm) and Ni (32-138 ppm) contents, together with high (Sr-87/Sr-86)(i) (0.70867-0.71060) and negative epsilon(Nd)(t) (-4.07 to - 6.80) values. Their zircon epsilon Hf(t) vary from -5.64 to +4.12, and their delta O-18 (6.0 to 6.9%0) are slightly higher than the average mantle value. The granodiorite has higher SiO2 and lower MgO contents, and varying zircon epsilon Hf(t) (-12.19 to -2.71) and delta O-18 (6.3 to 8.1%0). The rocks are characterized by enrichments in large ion lithophile elements (LILEs: e.g., Rb, Th, U, K) and light rare earth elements (LREEs), but depleted in high field strength elements (HFSEs), and have also high (Sr-87/Sr-86)(i) (0.71057-0.711860) and negative epsilon(Nd)(t) (-8.42 to - 9.14). Mafic microgranular enclaves (MMEs) in the granodiorite have intermediate SiO2, MgO, and trace elements and Sr-Nd-Hf-O isotope compositions between the high-Mg diorite and the granodiorite. Based on these geochemical and isotopic features, we interpreted that the high-Mg diorite was generated from the interaction of subducted sediment-derived melt with the overlying mantle wedge, whilst the granodiorite was sourced from the ancient continental crust with minor mantle-derived input. Mixing between the mantle derived high-Mg dioritic melt and the crustal-derived granodioritic melt may have formed the MMEs. Our new geochemical (incl. isotopic) data, combined with published ones ... |
| نوع الوثيقة: | report |
| اللغة: | English |
| Relation: | LITHOS; http://ir.gig.ac.cn/handle/344008/61426 |
| DOI: | 10.1016/j.lithos.2021.106074 |
| الاتاحة: | http://ir.gig.ac.cn/handle/344008/61426 https://doi.org/10.1016/j.lithos.2021.106074 |
| رقم الانضمام: | edsbas.F558E211 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1016/j.lithos.2021.106074 |
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