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 |
Received:September 21, 2015 Revised:December 20, 2016 点此下载全文 |
引用本文:DUAN 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 Deposits,36(1):25~37 |
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Author Name | Affiliation | DUAN ShiGang | MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China College of Earth Science and Land Resources, Chang'an University, Xi'an 710054, Shaanxi, China | JIANG ZongSheng | MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China | ZHANG ZuoHeng | Chinese Academy of Geological Sciences, Beijing 100037, China | LI FengMing | Xinjiang Bureau of Geology and Mineral Resources, Urumqi 830000, Xinjiang, China | REN YaQiong | MLR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China |
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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 |
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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。 |
中文关键词:地球化学 磁黄铁矿 LA-ICP-MS Re-Os同位素 铜镍硫化物矿床 天宇 东天山 |
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Re-Os isotopic analysis of pyrrhotite from Tianyu Cu-Ni sulfide deposit in Eastern Tianshan Mountains, Xinjiang: Constraints on sources of ore-forming materials |
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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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