Geochronology and geochemistry of the Nanfen iron deposit in the Anshan-Benxi area, North China Craton: Implications for similar to 2.55 Ga crustal growth and the genesis of high-grade iron ores
文献类型：期刊论文
| 作者 | Zhu, Mingtian1; Dai, Yanpei1,2; Zhang, Lianchang1; Wang, Changle1,2; Liu, Li1,2 |
| 刊名 | PRECAMBRIAN RESEARCH
 |
| 出版日期 | 2015-05-01 |
| 卷号 | 260页码:23-38 |
| 关键词 | Banded Iron Formation High-grade Iron Ore Zircon U-pb Dating And Hf Isotope Neoarchean Crustal Growth North China Craton |
| DOI | 10.1016/j.precamres.2015.01.001 |
| 文献子类 | Article |
| 英文摘要 | The Nanfen iron deposit, situated in the Anshan-Benxi area of the North China Craton (NCC), hosts scattered banded iron formations (BIFs) and BIF-hosted high-grade iron orebodies (defined by FeOT >80 wt.%). The associated roof and bottom rocks, which occur in parallel to orebodies, are mica quartz schist and chlorite hornblende schist (locally interlayers), respectively. The PAAS-normalized rare earth element (REE) patterns indicate that quartz-magnetite banded iron formations (BIFs) are enriched in Heavy REEs with positive La, Eu and Y anomalies, indicating that the Nanfen BIF precipitated from a mixture of ambient seawater and submarine high-T hydrothermal fluids (similar to 0.1%). In addition, the BIF exhibits low concentrations of Al2O3 and TiO2 with depletion in HFSEs (high field strength elements, e.g., Nb, Ta, Zr, Hf and Ti), suggesting little contamination with continental detritus. Excepting lower Eu/Eu* values, the high-grade iron ores display similar geochemical features to the BIF, likely implying that they have a same iron source but did not form synchronously. Electron microprobe analyses (EMPA) and in situ LA-ICP-MS analyses reveal that in relative to the magnetite grains in high-grade ores, the magnetite grains in the BIF contain higher MnO, MgO and Zn concentrations, and lower Al2O3 and REE abundances, implying different formation conditions. Thus, we argue that high-grade ores are likely to be alteration products of primary BIFs. Chlorite hornblende schist (meta-basalt) samples exhibit low SiO2 contents (43.78-50.30 wt.%) with flat chondrite-normalized REE and N-MORB-normalized trace element patterns, which are similar to those of BABB (back-arc basin basalt). The zircon U-Pb dating results indicate that magmatic and metamorphic zircons from chlorite hornblende schist formed at approximately 2552 Ma and 2482 Ma, respectively. The former volcanic age could constrain the deposition age of the Nanfen BIF, and the latter reflects a subsequent metamorphic event, which is also reflected by the similar to 2480 Ma hydrothermal zircons selected from the BIF. Moreover, most zircons from chlorite hornblende schist have positive epsilon(Hf)(t) values (0.22-7.96) close to the depleted mantle evolutionary curve, implying that the source magma were derived from a depleted mantle with some contamination from ancient crust. Hence, we propose that the Nanfen BIF is a Neoarchean Algoma-type BIF, and its deposition was most likely benefited due to crustal growth. (C) 2015 Elsevier B.V. All rights reserved. |
| WOS关键词 | RARE-EARTH-ELEMENTS ; GREAT OXIDATION EVENT ; EASTERN HEBEI PROVINCE ; SINO-KOREAN CRATON ; U-PB GEOCHRONOLOGY ; TRACE-ELEMENT ; FORMATION AGE ; HF ISOTOPES ; TECTONIC EVOLUTION ; CONTINENTAL-CRUST |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000350935700002 |
| 资助机构 | National 973 Project of China(2012CB416601) ; National 973 Project of China(2012CB416601) ; NSFC(41202066) ; NSFC(41202066) ; National 973 Project of China(2012CB416601) ; National 973 Project of China(2012CB416601) ; NSFC(41202066) ; NSFC(41202066) |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/62552]  |
| 专题 | 地质与地球物理研究所_中国科学院矿产资源研究重点实验室 |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China |
| 推荐引用方式 GB/T 7714 | Zhu, Mingtian,Dai, Yanpei,Zhang, Lianchang,et al. Geochronology and geochemistry of the Nanfen iron deposit in the Anshan-Benxi area, North China Craton: Implications for similar to 2.55 Ga crustal growth and the genesis of high-grade iron ores[J]. PRECAMBRIAN RESEARCH,2015,260:23-38. |
| APA | Zhu, Mingtian,Dai, Yanpei,Zhang, Lianchang,Wang, Changle,&Liu, Li.(2015).Geochronology and geochemistry of the Nanfen iron deposit in the Anshan-Benxi area, North China Craton: Implications for similar to 2.55 Ga crustal growth and the genesis of high-grade iron ores.PRECAMBRIAN RESEARCH,260,23-38. |
| MLA | Zhu, Mingtian,et al."Geochronology and geochemistry of the Nanfen iron deposit in the Anshan-Benxi area, North China Craton: Implications for similar to 2.55 Ga crustal growth and the genesis of high-grade iron ores".PRECAMBRIAN RESEARCH 260(2015):23-38. |
入库方式： OAI收割
来源：地质与地球物理研究所
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