| 孙志远,龙灵利,王玉往,罗照华,胡其涛,王孟龙.新疆东天山红云滩铁矿床磁铁矿标型和硫同位素特征及其意义[J].矿产勘查,2018,9(12):2324-2338 |
| 新疆东天山红云滩铁矿床磁铁矿标型和硫同位素特征及其意义 |
| Typomorphism of magnetite and sulfur isotopic characteristics of the Hongyuntan iron deposit in Eastern Tianshan Mountains and its significance |
| 投稿时间：2018-07-15 |
| DOI： |
| 中文关键词: 磁铁矿 矿物化学 硫同位素 红云滩铁矿床 东天山 |
| 英文关键词: magnetite, mineral chemistry, sulfur isotopes, Hongyuntan iron deposit, eastern Tianshan |
| 基金项目:国家重点基础发展研究计划项目(编号:2014CB440803、2017YFC0601204)资助。 |
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| 中文摘要: |
| 红云滩铁矿床是新疆东天山阿奇山-雅满苏构造带中一个富铁矿床,矿体赋存于石炭系雅满苏组安山质凝灰岩和晶屑凝灰岩中,呈层状、似层状或透镜状产出,矿区分为东西两个矿段。矿石以块状和浸染状为主,脉状次之,局部有条带状和网脉状。矿石矿物主要为磁铁矿,脉石矿物组合为绿泥石、石榴石、透闪石、阳起石、绿帘石和石英等。根据野外及镜下观察,可将红云滩矿床分为两期3个成矿阶段,按阶段分别为(1)火山喷溢成矿阶段,(2)矽卡岩+磁铁矿阶段,(3)石英-硫化物+磁铁矿阶段,磁铁矿主要形成于矽卡岩+磁铁矿阶段。磁铁矿的电子探针数据显示FeO含量变化较大,在88.80%~93.19%之间,具有低的TiO2含量(0~0.21%),较高的SiO2(0~1.77%)、MgO(0~1.19%)、CaO(0~1.51%)、Al2O3(0~0.94%)含量,显示出热液型磁铁矿特征。TiO2-Al2O3-(MgO+MnO)、TiO2-Al2O3-MgO和(Ca+Al+Mn) vs (Ti+V)图解表明,磁铁矿形成与火山沉积和火山热液活动有密切关系。红云滩铁矿床黄铁矿硫同位素变化范围较大,δ34S值在-3.8‰~4.7‰之间,指示成矿物质主要来自深部岩浆系统。红云滩铁矿床的形成在时间上和空间上均与海底火山活动密切相关,结合矿床地质特征,认为红云滩铁矿为火山喷溢-火山热液型矿床。 |
| 英文摘要: |
| The Hongyuntan magnetite deposit, which is located in the Aqishan-Yamansu belt of the Eastern Tianshan, Xinjiang, is hosted within Carboniferous submarine volcanic-sedimentary sequences. The orebodies are hosted in the andesitic tuff, crystal tuff, and tuffaceous siltstone of the Yamansu Formation. Structurally, these orebodies display stratiform, stratoid or lenticular forms, and they are in conformable contact with volcanic rocks. This deposit contains two ore sections:the east section and the west section. Massive, disseminated, banded, and veined ores are found in the Hongyuntan ore district. Ore minerals include magnetite and gangue minerals include chlorite, garnet, tremolite, actinolite, epidote, and quartz. On the basis of paragenesis and the crosscutting relationships of these minerals, we can identify two principal periods, and three mineralization stages:(1) volcanic eruption mineralization stage, (2) skarn+magnetite stage and (3) quartz-sulfides+magnetite stage. Electron microprobe analyses show that the magnetite crystals have various content of FeO (88.80%~93.19%), low content of TiO2 (0~0.21%), and high content of SiO2(0~1.77%), MgO (0~1.19%), CaO (0~1.51%), Al2O3(0~0.94%), which show the characteristics of hydrothermal magnetite.The triangle diagrams of TiO2-Al2O3-(MgO+MnO) and TiO2-Al2O3-MgO in addition to the Ca+Al+Mn versus Ti+V diagram show that the Hongyuntan deposit was genetically closely related to volcanic sediment-hydrothermal activity. Sulfur isotopes (δ34S =-3.8‰~4.7‰) of pyrites in the Hongyuntan iron deposit indicate that deep-seated magma provided ore-forming materials but experienced mixing with seawater in the late stage. The Hongyuntan magnetite deposit is spatially and temporally associated with volcanism and may be genetically related to it. Combined with the ore deposit characteristics and the results of chemical analyses, we speculate that the Hongyuntan deposit is a submarine volcanic hydrothermal deposit. |
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