| 陈伟军.内蒙古鸡冠山斑岩型钼矿床S、Pb同位素组成：对成矿物质来源的指示[J].地质与勘探,2020,56(1):68-77 |
| 内蒙古鸡冠山斑岩型钼矿床S、Pb同位素组成：对成矿物质来源的指示 |
| S, Pb isotopic composition of the Jiguanshan porphyry molybdenum deposit in Inner Mongolia: Indication of ore-forming material sources |
| 投稿时间：2019-01-31 修订日期：2019-12-10 |
| DOI：10.12134/j.dzykt.2020.01.007 |
| 中文关键词: 成矿物质来源 S同位素 Pb同位素 鸡冠山斑岩型钼矿床 内蒙古 |
| 英文关键词: source of ore-forming materials, S isotope, Pb isotopes, Jiguanshan porphyry molybdenum deposit, Inner Mongolia |
| 基金项目:国家自然科学基金（编号：41602099）资助 |
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| 中文摘要: |
| 内蒙古鸡冠山钼矿床位于中亚—蒙古巨型造山带东段，是西拉沐沦钼金属成矿带中一典型的大型斑岩型钼矿床。矿床产于燕山晚期火山侵入杂岩中，矿体与岩体关系密切，矿化类型以细脉浸染状斑岩型矿化为主。在野外地质观察的基础上，本文对矿石矿物黄铁矿、辉钼矿进行了S同位素组成分析，对矿床围岩全岩及黄铁矿单矿物进行了Pb同位素组成分析。结果表明钼矿石δ34S变化范围为4.617‰～7.072‰，平均值为5.653‰，离散度小，硫化物δ34S值全为正值，表明矿石中S源是均一的。辉钼矿δ34S变化范围为4.617 ‰～5.351‰，平均值为4.875‰。硫同位素比值5.653‰具花岗质岩浆硫特征，推测其硫可能主要来源于下地壳岩浆源，并有一定量的地幔物质的混入。全岩的206Pb/204 Pb、207Pb/204Pb和208Pb/204Pb分别为17.876～19.618、15.519～15.609和38.111～40.408，表明鸡冠山钼矿床围岩的全岩铅同位素组成均变化较大。矿石矿物黄铁矿的206Pb/204 Pb、207Pb/204Pb和208Pb/204Pb分别为17.781～17.830、15.523～15.526和38.084～38.102，表明矿石矿物铅同位素组成变化较小。围岩全岩和矿石硫化物的铅同位素投影点均落在造山带演化线的下方，表明铅很可能源于地幔或者下地壳。 |
| 英文摘要: |
| The Jiguanshan molybdenum deposit, inner Mongolia, is located in the middle of Xilamulun Mo metallogenic belt in the northern margin of North China Craton, is a typical large large-porphyry type molybdenum deposit. The deposit occurs within the volcanic-intrusive complex, is characterized by the veinlet and disseminate mineralization. On the basis of field geological observation, this paper deals with ore minerals, pyrite, molybdenite S isotopic composition analysis of whole rock and surrounding rock of the ore deposits, single mineral analyzed the Pb isotopic composition of pyrite. Results show that the sulphide δ34S value all positive, molybdenum stone δ34S range of 4.617‰~7.072‰, with a mean of 5.653‰, the discrete degree of small, show that the uniformity of S in the ore source. Molybdenite δ34S range of 4.617‰~5.351‰, with a mean of 4.875‰. Sulfur isotope ratio 5.653‰ has the feature of granitic magma sulfur, speculated that the sulfur may mainly comes from the lower crust magma source, and have a certain amount of mantle material mixed with. Whole rock 206Pb/204 Pb, 207 Pb /204 Pb and 208 Pb/204 Pb were 17.876 ~ 19.618, 15.519 ~ 15.609 and 38.111 ~ 40.408, show that the Jiguanshan molybdenum deposit of whole rock lead isotopic composition changes are larger. Single mineral ore mineral pyrite in 206Pb/204 Pb, 207Pb/204Pb and 208Pb /204Pb were 17.781 ~ 17.830, 15.523 ~ 15.526 and 38.084 ~ 38.102, indicates that ore mineral Pb isotopic composition changes small. Pb isotope of surrounding rock of whole rock and ore sulfides projection points are below the falls in line with the evolution of orogenic belt, show that Pb probably originated from mantle or lower crust. |
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