In-site mineral geochemistry and whole-rock Fe isotopes of the quartz-magnetite-pyroxene rocks in the Wuyang area, North China Craton: Constraints on the genesis of the pyroxene-rich BIF
文献类型：期刊论文
| 作者 | Lan, Caiyun1; Long, Xiaoping1; Zhao, Taiping2; Zhai, Mingguo3 |
| 刊名 | PRECAMBRIAN RESEARCH
 |
| 出版日期 | 2019-10-01 |
| 卷号 | 333页码:15 |
| 关键词 | BIF Pyroxene Magnetite Metamorphism North China Craton |
| ISSN号 | 0301-9268 |
| DOI | 10.1016/j.precamres.2019.105445 |
| 英文摘要 | Quartz-magnetite-pyroxene (QMP) rocks with high Fe contents are of greatly economic and petrological importance and generally occur within the oldest and largest exposures of supracrustal rocks preserved on Earth. However, the chemical composition and genesis of QMP rocks remain unclear. To constrain the protolith and genesis, we present new whole-rock geochemistry and Fe isotopic data, mineral EPMA and LA-ICP-MS analysis and X-ray mapping for the QMP rocks in the Wuyang area, North China Craton. The Wuyang QMP rocks have undergone high-temperature metamorphism and have special mineral assemblages with coexisting magnetite, quartz, clinopyroxene and variable orthopyroxene. Pyroxenes of the Wuyang QMP rocks show very distinct major, trace and rare earth element (REE) compositions from those of the nearby pyroxene-marbles and pyroxenite intrusions. Such difference excludes a contact metamorphic origin for pyroxenes of the QMP rocks. X-ray elemental mapping suggests that Fe-poor carbonate minerals (dolomite and calcite) and quartz inclusions are well preserved in these pyroxene grains and no reaction phenomenon can be observed between them, indicating that these pyroxenes are not the product of metamorphic decarbonation reactions of pre-existing sedimentary silica and Fe-rich carbonate phase. Shale-normalized REE + Y patterns of the whole-rock samples and pyroxenes display geochemical features consistent with classic banded iron formations (BIFs), which show light REE depletion, positive La-SN, Eu-SN and Y-SN anomalies. This indicates that the geochemical features are compositionally inherited from their original pure chemical sediments. The Wuyang QMP rocks are therefore considered as pyroxene-rich BIF. Neotocite and hisingerite inclusions in pyroxene grains from the QMP rocks could be metamorphic products of some early Fe- and Mn-rich silicates before pyroxene. Moreover, the Wuyang QMP rocks are enriched in light iron isotopes similar to other Fe- and Ca-rich minerals in Archean BIFs. Therefore, we inferred that pyroxene from the QMP rocks could result from dehydration of initial sedimentary hydrous Ca-, Mg- and Mn-containing Fe(II)-silicate gel during diagenesis and re-crystallization in later metamorphism, providing a new interpretation for the origin of pyroxene-rich BIF. |
| WOS关键词 | BANDED IRON-FORMATION ; RARE-EARTH-ELEMENTS ; NUVVUAGITTUQ SUPRACRUSTAL BELT ; DALES-GORGE-MEMBER ; LA-ICP-MS ; HENAN PROVINCE ; CRUSTAL EVOLUTION ; TAIHUA COMPLEX ; WEST GREENLAND ; ORIGIN |
| 资助项目 | National Natural Science Foundation of China[41890834] ; National Natural Science Foundation of China[41602078] ; National Natural Science Foundation of China[41573041] ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; China Postdoctoral Science Foundation[2019M650272] |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000493218900017 |
| 出版者 | ELSEVIER |
| 资助机构 | National Natural Science Foundation of China ; National Natural Science Foundation of China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; China Postdoctoral Science Foundation ; China Postdoctoral Science Foundation ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; China Postdoctoral Science Foundation ; China Postdoctoral Science Foundation ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; China Postdoctoral Science Foundation ; China Postdoctoral Science Foundation ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; MOST Special Fund from the State Key Laboratory of Continental Dynamics, Northwest University, China ; China Postdoctoral Science Foundation ; China Postdoctoral Science Foundation |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/95750]  |
| 专题 | 地质与地球物理研究所_岩石圈演化国家重点实验室 |
| 通讯作者 | Long, Xiaoping |
| 作者单位 | 1.Northwest Univ, Dept Geol, State Key Lab Continental Dynam, Xian 710069, Shaanxi, Peoples R China 2.Chinese Acad Sci, Guangzhou Inst Geochem, Key Lab Mineral & Metallogeny, Guangzhou 510640, Guangdong, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Lan, Caiyun,Long, Xiaoping,Zhao, Taiping,et al. In-site mineral geochemistry and whole-rock Fe isotopes of the quartz-magnetite-pyroxene rocks in the Wuyang area, North China Craton: Constraints on the genesis of the pyroxene-rich BIF[J]. PRECAMBRIAN RESEARCH,2019,333:15. |
| APA | Lan, Caiyun,Long, Xiaoping,Zhao, Taiping,&Zhai, Mingguo.(2019).In-site mineral geochemistry and whole-rock Fe isotopes of the quartz-magnetite-pyroxene rocks in the Wuyang area, North China Craton: Constraints on the genesis of the pyroxene-rich BIF.PRECAMBRIAN RESEARCH,333,15. |
| MLA | Lan, Caiyun,et al."In-site mineral geochemistry and whole-rock Fe isotopes of the quartz-magnetite-pyroxene rocks in the Wuyang area, North China Craton: Constraints on the genesis of the pyroxene-rich BIF".PRECAMBRIAN RESEARCH 333(2019):15. |
入库方式： OAI收割
来源：地质与地球物理研究所
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