中国地质2019，Vol.46Issue(1)：115-125,11.DOI:10.12029/gc20190107
雅鲁藏布江缝合带西段错不扎铬铁矿特征及形成环境
Features of the Cuobuzha podiform chromitite along western Yarlung Zangbo suture zone in Tibet:Implications for its tectonic setting
摘要
Abstract
Most of chromitite ores produced in China are from the Yarlung Zangbo ophiolite belt (YZSZ), which is divided into three parts: the eastern part (Qu Shui to Mo Tuo), the middle part (Ang Ren to Ren Bu) and the western part (Saga to the Sino-Indian border). Furthermore, the western part contains north sub-belt and south sub-belt. For a long time, most of studies have focused on the eastern part and middle part, with very insufficient studies conducted on the western part, especially on the north subbelt, which inhibits mineral exploration along the YZSZ. Cuobuzha ophiolite is located in the north sub-belt, which occurs along a NW-SE trending belt and is mainly composed of harzburgite with diabase dykes. The field investigation discovered several chromite orebodies 0.5-1 m long and 0.2-0.5 m thick within the ophiolite. All of the ores are massive. The analytical results by electron-probe micro-analyzer (EPMA) show that the Cuobuzha chromitite is of typical high-Cr variety with Cr number [Cr#= 100× Cr/ (Cr + Al) ] ranging from 75 to 78, and Mg number [Mg#= 100 × Mg/ (Mg + Fe2 +) ] ranging from 66 to 69. Calculated results show that the ratio of FeO/MgO ranges from 0.51 to 0.65, and that the values of Al2O3 and TiO2 are 11.27％-12.1 ％ and 0.19％-0.4 ％, respectively, revealing that the Cuobuzha chromitite has boninitic affinities. However, the occurrence of clinopyroxene exsolution indicates that it should have experienced a deep process.关键词
雅鲁藏布江缝合带/错不扎铬铁矿/铬尖晶石/玻安质岩浆/单斜辉石出溶体Key words
Yarlung Zangbo Suture Zone/Cuobuzha chromitite/Cr-spinel/Boninitic magma/clinopyroxene exsolution分类
天文与地球科学引用本文复制引用
赵慧,杨经绥,刘飞,熊发挥,连东洋,姚虎,董玉飞..雅鲁藏布江缝合带西段错不扎铬铁矿特征及形成环境[J].中国地质,2019,46(1):115-125,11.基金项目
国家科学技术部项目(2014DFR21270) （2014DFR21270）
中国地质调查局项目(DD20160023-01,DD20160022-01) （DD20160023-01,DD20160022-01）
国家自然科学基金项目(41720104009,41672063,41773029)联合资助 （41720104009,41672063,41773029）
