Amphibole and whole-rock geochemistry of early Late Jurassic diorites, Central Tibet: Implications for petrogenesis and geodynamic processes
文献类型：期刊论文
| 作者 | Hu, Wan-Long2,3; Wang, Qiang2,3,4; Yang, Jin-Hui1; Tang, Gong-Jian2,4; Qi, Yue2; Ma, Lin2; Yang, Zong-Yong2; Sun, Peng2 |
| 刊名 | LITHOS
 |
| 出版日期 | 2020-10-01 |
| 卷号 | 370页码:17 |
| ISSN号 | 0024-4937 |
| 关键词 | Amphibole Diorite Arc magma Thermobarometry Central Tibet |
| DOI | 10.1016/j.lithos.2020.105644 |
| 英文摘要 | Arc magmas are generated by complex geological processes in subduction settings. Due to the complexity of source materials and geological processes, the genesis of arc magmatic rocks can be difficult to disentangle. Here, we report on diorites from the Kenama area of the middle-eastern part of the Bangong-Nujiang suture zone in central Tibet. New SIMS and IA-ICP-MS zircon U-Pb dating for three diorite samples indicates that they crystallized during the early Late Jurassic (ca. 161 Ma). The diorites can be divided into two groups based on whole-rock major element compositions and mineralogical characteristics: Group I diorites with relatively low SiO2 (47.6-53.4 wt%), and high MgO (4.97-9.10 wt%) and amphibole contents (50-54 vol%); and Group II diorites with slightly higher SiO2 (56.9-59.5 wt%), and low MgO (2.9-3.8 wt%) and amphibole contents (25-30 vol%). The Group I diorites exhibit relative enrichment in light rare earth element (LREE) (La/Yb)/N = 5.7-10.5) with slightly negative Eu anomalies, and are characterized by enrichment of large ion lithophile elements (ULEs; K, Rb, Ba, Th, and U), the depletion of high field strength elements (HFSEs: Nb, Ta, Zr, Elf, and Ti). The Group I diorites have relatively high initial Sr-87/ Sr-86 ratios (0.7073-0.7094), variably negative epsilon(Nd)(t) values ( -103 to -5.9), negative zircon epsilon(Hf)(t) values (-14.8 to-4.4), and slightly elevated delta O-18 values (6.5 parts per thousand-73 parts per thousand). The Group II diorites show similar trace element characteristics to Group I. They also have high initial Sr-87/Sr-86 ratios (0.7083-0.7087), uniformly negative epsilon(Nd)(t) values (-9.5 to -9.0), negative zircon epsilon(Hf)(t) values (-10.3 to -4.2), and elevated delta O-18 values (6.6 parts per thousand-7.5 parts per thousand). Amphiboles from Group I and Group II diorites have low Al2O3 contents (3.6-9.9 wt% and 5.6-85 wt%, respectively), and formed at similar P-T conditions (751-871 degrees C and 69-226 MPa and 745-832 degrees C et and 77-162 MPa, respectively). On primitive mantle-normalized spider diagrams, these low-Al amphibole grains have slightly convex upward REE patterns with distinctly negative anomalies in Pb, Sr, Eu, Zr, Hf, and Ti, suggesting that amphiboles from both groups crystallized from the similar arc magmas after plagioclase and magnetite crystallization. These mineralogical, geochemical and isotopic characteristics suggest that both groups of Kenama diorites probably originated from an enriched lithospheric mantle metasomatized by subducted oceanic sediment-derived melts. Their parental magmas may have similar geochemical characteristics and underwent varying degrees of accumulation and fractional crystallization. The Group I diorites were likely generated by accumulation of amphibole and fractional crystallization of olivine, clinopyroxene, and plagioclase from mafic magmas, and the Group II diorites were formed by the fractional crystallization of clinopyroxene and plagioclase from mafic magmas that were geochemically similar to the Group I diorites. In combination with regional geology, in particular adjacent ophiolites, high-magnesian andesitic rocks and Cretaceous sedimentary rocks, we conclude that all of the Kenama diorites were probably generated in an early Late Jurassic arc setting related to the subduction of the Bangong-Nujiang Tethys oceanic lithosphere. (C) 2020 Elsevier B.V. All rights reserved. |
| WOS关键词 | ZIRCON U-PB ; NUJIANG TETHYAN OCEAN ; NORTHERN LHASA TERRANE ; HIGH-MG ANDESITES ; HF-O ISOTOPES ; ARC MAGMAS ; CRUSTAL GROWTH ; FRACTIONAL CRYSTALLIZATION ; SOUTHERN QIANGTANG ; WORKING REFERENCE |
| 资助项目 | Strategic Priority Research Program (A) of the Chinese Academy of Sciences[XDA2007030402] ; National Natural Science Foundation of China[41630208] ; National Natural Science Foundation of China[91855215] ; Second Tibetan Plateau Scientific Expedition and Research (STEP)[2019QZKK0702] ; National Key R&D Program of China[2016YFC0600407] ; Key Program of the Chinese Academy of Sciences[QYZDJ-SSW-DQC026] ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project)[135TP201601] |
| WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
| 语种 | 英语 |
| 出版者 | ELSEVIER |
| WOS记录号 | WOS:000558896300029 |
| 资助机构 | Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; National Key R&D Program of China ; National Key R&D Program of China ; Key Program of the Chinese Academy of Sciences ; Key Program of the Chinese Academy of Sciences ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) ; Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; National Key R&D Program of China ; National Key R&D Program of China ; Key Program of the Chinese Academy of Sciences ; Key Program of the Chinese Academy of Sciences ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) ; Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; National Key R&D Program of China ; National Key R&D Program of China ; Key Program of the Chinese Academy of Sciences ; Key Program of the Chinese Academy of Sciences ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) ; Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; Strategic Priority Research Program (A) of the Chinese Academy of Sciences ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; Second Tibetan Plateau Scientific Expedition and Research (STEP) ; National Key R&D Program of China ; National Key R&D Program of China ; Key Program of the Chinese Academy of Sciences ; Key Program of the Chinese Academy of Sciences ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) ; Guangzhou Institute of Geochemistry, Chinese Academy of Science (GIGCAS 135 project) |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/97628]  |
| 专题 | 地质与地球物理研究所_岩石圈演化国家重点实验室 |
| 通讯作者 | Wang, Qiang |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 2.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Isotope Geochem, Guangzhou 510640, Peoples R China 3.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 100049, Peoples R China 4.CAS Ctr Excellence Tibetan Plateau Earth Sci, Beijing 100101, Peoples R China |
| 推荐引用方式 GB/T 7714 | Hu, Wan-Long,Wang, Qiang,Yang, Jin-Hui,et al. Amphibole and whole-rock geochemistry of early Late Jurassic diorites, Central Tibet: Implications for petrogenesis and geodynamic processes[J]. LITHOS,2020,370:17. |
| APA | Hu, Wan-Long.,Wang, Qiang.,Yang, Jin-Hui.,Tang, Gong-Jian.,Qi, Yue.,...&Sun, Peng.(2020).Amphibole and whole-rock geochemistry of early Late Jurassic diorites, Central Tibet: Implications for petrogenesis and geodynamic processes.LITHOS,370,17. |
| MLA | Hu, Wan-Long,et al."Amphibole and whole-rock geochemistry of early Late Jurassic diorites, Central Tibet: Implications for petrogenesis and geodynamic processes".LITHOS 370(2020):17. |
入库方式： OAI收割
来源：地质与地球物理研究所
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