Geochemical characteristics and tectonic significance of podiform chromitite in the Qielihu in the middle segment of the Bangong-Nujiang suture, Tibet

被引：0
|
作者：
Yan J. [1 ]
Xiong F. [1 ,2 ]
Xu X. [1 ,2 ]
Zhang C. [3 ]
Lu Y. [4 ]
He L. [5 ]
Wang T. [6 ]
Yang J. [1 ,7 ]
机构：
[1] CARMA (Center for Advanced Research on Mantle), Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources, Institute of Geology, Chinese Academy of Geological Sciences, Beijing
[2] Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou), Guangdong, Guangzhou
[3] Second Geo-Exploration Institute of CMGB, Fujian, Fuzhou
[4] CNPC XDEC Geological Research Institute, Xijiang, Karamay
[5] Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing
[6] No.5 Geological Survey Party, Tibet Autonomous Region Geological and Mineral Exploration and Development Bureau, Golumd, Qinghai
[7] School of Earth Sciences and Engineering, Nanjing University, Jiangsu, Nanjing
来源：
Dizhi Xuebao/Acta Geologica Sinica | 2022年 / 96卷 / 12期
关键词：
Bangong-Nujiang suture zone; chromitite; mantle peridotite; ophiolite; Qielihu; whole rock geochemistry;
D O I：
10.19762/j.cnki.dizhixuebao.2022197
中图分类号：
O61 [无机化学]; TQ [化学工业];
学科分类号：
070301 ; 0817 ; 081704 ;
摘要：
Qielihu ophiolite is located to the middle part of the Bangong-Nujiang suture which is rich in chromitite resources. Qielihu ophiolite is mainly composed of altered mantle peridotite, gabbro and diabase, and chromite orebodies are lenticular in the interior of mantle peridotite.The olivine Fo (90.06~ 90.74) and chromite Cr# (67.45~85.42) of the mantle peridotite from the Qielihu are relatively high, the whole rock is rich in MgO, LREE and large ion lithophile elements (such as Rb, Ba, etc.), and depleted in Al2O3,CaO, high field strength elements (such as Th, Ta, Ce, Nb) and PPGE (Rh, Pt, Pd). These characteristics are similar to other mantle peridotites in the Bangong-Nujiang suture zone, indicating that they have the characteristics of Abyssal mantle peridotite and Forearc mantle peridotite. Meantime, it has gone through the process of early high degree melt extraction and late melt metasomatism. The Qielihu chromitite ore has a dense massive and disseminated structure and contains many kinds of inclusions such as spinel, chalcopyrite, galena and so on. The Cr# value of chromitite is 65.5~75.8 and the Mg # value is 64.89~76.04. The equilibrium melt shows the affinity of vitreous melt. Compared with mantle peridotite, the IPGE and PPGE fractionation of Qielihu chromitite is more obvious. The ΔlgfO2 (FMQ) values of mantle peridotite and chromitite are similar, ranging from -1.97 to 0.69, indicating that they are derived from the same tectonic setting. Compared with other ophiolites, it is considered that the ophiolite in the Bangong-Nujiang suture originated from the mid-ocean ridge environment and its formation experienced multi-stage evolution. © 2022 Geological Society of China. All rights reserved.
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页码：4294 / 4311
页数：17
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