| Geochemistry and iron isotope systematics of coexisting Fe-bearing minerals in magmatic Fe-Ti deposits: A case study of the Damiao titanomagnetite ore deposit, North China Craton | |
Wei, Youqing1,2,4; Niu, Yaoling1,3,4,5; Gong, Hongmei1,4; Duan, Meng1,4; Chen, Shuo1,4; Guo, Pengyuan1,4; Sun, Pu1,4
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| 2020-05-01 | |
| Source Publication | GONDWANA RESEARCH
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| ISSN | 1342-937X |
| Volume | 81Pages:240-251 |
| Corresponding Author | Wei, Youqing(yqwei49@126.com) ; Niu, Yaoling(yaoling.niu@durham.ac.uk) |
| Abstract | Geochemical and iron isotopic compositions of magnetite, ilmenite and pyrite separates from the Fe-Ti oxide ores hosted in the Damiao anorthosite-type Fe-Ti ore deposit were analyzed to investigate sub-solidus cooling history of the titanomagnetite. The Fe-Ti oxides form two series of solid solutions, namely, ulvospinel-magnetite (Usp-Mt(ss)) and hematite-ilmenite (Hem-Ilm(ss)) solid solutions. The magnetite separates have 14-27 mol% ulvospinel, while the ilmenite separates have 5-8 mol% hematite. Major element compositions of the mineral separates suggest that the ilmenites were mainly exsolved from the Usp-Mt(ss) by oxidation of ulvospinel in the temperature range of similar to 820-600 degrees C and experienced inter-oxide re-equilibration with the magnetites. Associated with the exsolution is the substantial inter-mineral iron isotope fractionation. The magnetite separates are characterized by high delta Fe-57 (+0.27 - +0.65 parts per thousand), whereas the ilmenite separates have lower delta Fe-57 (-0.65 to -028 parts per thousand). Two types of pyrite are petrographically observed, each of which has a distinctive iron isotope fingerprint. Type I pyrite (pyrite(I)) with higher delta Fe-57 (delta Fe-57 = +0.63 - +0.95 parts per thousand) is consistent with magmatic origin, and type II pyrite (pyrite(II)) with lower delta Fe-57 (delta Fe-57 = -0.90 to -0.11 parts per thousand) was likely to have precipitated from fluids. Iron isotopic fingerprints of the pyrite(I) probably indicate variations of oxygen fugacity, whereas those of the pyrite(II) may result from fluid activities. The iron isotopic fractionation between the magnetite and ilmenite is the net result of sub-solidus processes (induding ulvospinel oxidation and inter-oxide re-equilibration) without needing varying oxygen fugacity albeit its presence. Although varying composition of magnetite-ilmenite pairs reflects variations of oxygen fugacity, inter-oxide iron isotopic fractionation does not. (C) 2019 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. |
| Keyword | Iron isotopes Titanomagnetite Exsolution Sub-solidus cooling |
| DOI | 10.1016/j.gr.2019.12.001 |
| Indexed By | SCI |
| Language | 英语 |
| Funding Project | National Natural Science Foundation of China (NSFC)[41806080] ; National Natural Science Foundation of China (NSFC)[41630968] ; National Natural Science Foundation of China (NSFC)[41776067] ; 111 Project of China[B18048] ; Shandong Provincial Key Laboratory of Depositional Mineralization & Sedimentary Mineral of China[DMSM2018059] |
| WOS Research Area | Geology |
| WOS Subject | Geosciences, Multidisciplinary |
| WOS ID | WOS:000523559700006 |
| Publisher | ELSEVIER |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.qdio.ac.cn/handle/337002/167060 |
| Collection | 海洋地质与环境重点实验室 |
| Corresponding Author | Wei, Youqing; Niu, Yaoling |
| Affiliation | 1.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 2.Shandong Univ Sci & Technol, Shandong Prov Key Lab Deposit Mineralizat & Sedim, Qingdao 266590, Peoples R China 3.China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China 4.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Geol, Qingdao 266061, Peoples R China 5.Univ Durham, Dept Earth Sci, Durham HD1 3LE, England |
| First Author Affilication | Institute of Oceanology, Chinese Academy of Sciences |
| Corresponding Author Affilication | Institute of Oceanology, Chinese Academy of Sciences |
| Recommended Citation GB/T 7714 | Wei, Youqing,Niu, Yaoling,Gong, Hongmei,et al. Geochemistry and iron isotope systematics of coexisting Fe-bearing minerals in magmatic Fe-Ti deposits: A case study of the Damiao titanomagnetite ore deposit, North China Craton[J]. GONDWANA RESEARCH,2020,81:240-251. |
| APA | Wei, Youqing.,Niu, Yaoling.,Gong, Hongmei.,Duan, Meng.,Chen, Shuo.,...&Sun, Pu.(2020).Geochemistry and iron isotope systematics of coexisting Fe-bearing minerals in magmatic Fe-Ti deposits: A case study of the Damiao titanomagnetite ore deposit, North China Craton.GONDWANA RESEARCH,81,240-251. |
| MLA | Wei, Youqing,et al."Geochemistry and iron isotope systematics of coexisting Fe-bearing minerals in magmatic Fe-Ti deposits: A case study of the Damiao titanomagnetite ore deposit, North China Craton".GONDWANA RESEARCH 81(2020):240-251. |
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