投稿时间：2015-09-21
修订日期：2016-12-20
网络发布日期：2017-03-11
中文摘要:天宇岩浆铜镍硫化物矿床的矿体由浸染状矿体和块状矿体组成。采用同位素稀释Triton-plus测定了浸染状矿石和块状矿石的磁黄铁矿Re-Os同位素比值。结果表明：浸染状矿石w（Re）为11.82×10-9~45.28×10-9，w（Os）为0.944×10-9~8.528×10-9，187Os/188Os初始比值为0.885~2.332，γOs为607~1763；块状矿石w（Re）为49.38×10-9~315.10×10-9，w（Os）为0.191×10-9~42.420×10-9，187Os/188Os初始比值为0.654~3.322，γOs为423~2555。Re、Os含量、同位素组成和特征值表明，该矿床物质为壳-幔混合来源，块状矿石可能比浸染状矿石经历了更强的地壳物质混染。浸染状矿体发育透闪石化、蛇纹石化、绿泥石化蚀变，表明存在岩浆期后热液活动，但块状矿体热液蚀变不明显，块状矿石的Re-Os同位素特征可能是与地壳岩石直接作用的结果。地壳混染作用发生在深部岩浆房，同时也发生在岩浆侵位及再次迁移过程中，这些过程造成块状矿体与浸染状矿体不同的同位素特征。
Abstract:The Tianyu Cu-Ni sulfide deposit is composed of spatially adjacent disseminated orebody and massive orebody, with the former formed earlier than the latter. In this study, the authors used isotopic dilution Triton-plus to determine the Re-Os isotopic ratios of pyrrhotite from the disseminated ore and the massive ore. In the disseminated ore, the Re content is from 11.82×10-9 to 45.28×10-9, the Os content is from 0.944×10-9 to 8.528×10-9, the initial 187Os/188Os ratio is from 0.885 to 2.332, and γOs is from 607 to 1763. In massive ore, the Re content is from 49.38×10-9 to 315.10×10-9, the Os content is from 0.191×10-9 to 42.420×10-9, the initial 187Os/188Os ratio is from 0.654 to 3.322, and γOs is from 423 to 2555. Element content, isotopic composition and characteristic values of Re and Os indicate that the ore-forming material in the Tianyu ore deposit was a mixed source of the crust and the mantle, and the massive ore experienced a higher degree of crustal contamination than the disseminated ore. Alteration of tremolite, serpentine and chlorite is developed in the disseminated ore, which indicates post-magmatic hydrothermal activity. In contrast, the massive ore does not show obvious magmatic hydrothermal alteration. Re-Os isotopic characteristics of the massive ore might have resulted from direct interaction with crustal rocks. As a result, crustal contamination was developed both in the deep magma chamber and at the present position of the orebody.
keywords:geochemistry pyrrhotite LA-ICP-MS Re-Os isotope copper-nickel sulfide deposit Tianyu Eastern Tianshan Mountains
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中图分类号：P597
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基金项目:本文为中央科研院所基本科研业务费项目（编号：K1202）、国家自然科学基金项目（编号：41203035）和地质矿产调查评价项目（编号：1212011220894-2、1212011090300）资助成果
引用文本：
段士刚,蒋宗胜,张作衡,李凤鸣,任雅琼.2017.东天山天宇铜镍硫化物矿床磁黄铁矿Re-Os同位素物质来源示踪[J].矿床地质,36(1):25~37DUAN ShiGang,JIANG ZongSheng,ZHANG ZuoHeng,LI FengMing,REN YaQiong.2017.Re-Os isotopic analysis of pyrrhotite from Tianyu Cu-Ni sulfide deposit in Eastern Tianshan Mountains, Xinjiang: Constraints on sources of ore-forming materials[J].Mineral Deposits36(1):25~37
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