The formation model of the carbonatite-syenite complex REE deposits in the east of Tibetan Plateau: A case study of Dalucao REE deposit

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	The formation model of the carbonatite-syenite complex REE deposits in the east of Tibetan Plateau: A case study of Dalucao REE deposit
	Liu Yan 1,2,3; Chen Chao 4; Shu XiaoChao 4; Guo DongXu 3; Li ZiJing 3; Zhao HaiXuan 5; Jia YuHeng 6
刊名	ACTA PETROLOGICA SINICA
	2017-07-01
卷号	33 期号:7 页码:1978-2000
关键词	Dalucao deposit Carbonatite-syenite complex Cryptoexplosion breccia type REE deposit Ore formation model
ISSN号	1000-0569
文献子类	Article
英文摘要	Mianning-Dechang (MD) REE Belt is located in the east of Tibetan Plateau and western Sichuan Province, southwestern China. It is controlled by a series of cenozoic strike-slip faults. Dalucao REE deposit is the only large deposit identified in the southern part of the MD REE Belt. Detailed comparison including metallogenic characteristics, host rock alteration, ore types, source of ore forming fluids and evolution of fluid inclusions of Dalucao and other deposits within MD REE Belt has been concluded based on latest geological surveys, studies on petrographic features; and the metallogenic process of carbonatite-type (including carbonatite-syenite complex) REE deposits is summarized The No. 1 and No. 3 orebodies in Dalucao deposit are both hosted in breccia pipes, located in carbonatite-syenite host rocks. Previous studies suggested that both No. 1 and No. 3 orebody in Dalucao deposit are formed at about 12Ma, but the latest research indicate there had already exist magmatic activity of carbonatite-syenite complexes at about 26. 49 +/- 0. 63 Ma. And the ores in Dalucao deposit are mainly classified as weathered and breccia type ores; the high levels of brecciation and weathering in the Dalucao deposit make it difficult to recognize the ore veins or gangue minerals from the hand specimen or field of microscope. Based on field observations, study of paragenetic association of minerals and analyses of inclusion in these REE deposits, the total mineralization in Dalucao deposit is similar to that of Maoniuping except for the smaller size of Dalucao REE deposit. The mineralization process can be divided into magmatic stage, pegmatite stage ( > 600 degrees C), high-temperature hydrothermal stage (450 similar to 350 degrees C) and low-temperature hydrothermal stage ( < 350 degrees C), the bastnasite precipitated during the later period of low-temperature hydrothermal stage. Based on the geological characteristics of inclusions found in pegmatite and hydrothermal fluids, the multiple episodes of explosive breccia activities leads to the addition of meteoric water and CO, deriving from the decarbonation of carbonatite; the density (0. 732 similar to 0. 631g/cm(3)) and pressure (2436 similar to 101bar) of the ore forming fluids gradually decreased. Meanwhile, various types of inclusions are found within the mineralization stages by the microscopic observation and Raman analysis. The variation of inclusion types changed from melt-inclusions to CO2-riched and gas-liquid inclusions bearing daughter minerals such as barite, fluorite and celestite, indicating the conversion process of ore-forming fluid changing from magmatic to hydrothermal fluid. The anion of inclusions in Dalucao REE deposit is mainly composed of SO42- ; CO2 count for most of gas in inclusions; the cations in the ore-forming fluids may mainly contain K+ , Na+ , Ca2+ , Sr2+ , Ba2+ and rare earth cations, all of these mentioned above reflected that the ore forming fluids are belong to SO42--Co-2-H2O system, and this is consistent with those of other REE deposits in the MD Belt. The mainly components of the ore forming liquids is magmatic water, meteoric water and CO2 originated from the decarbonation of carbonaite. And the latter may changed the 0 isotopic compositions of the hydrothermal calcite and bastnasite relative to the bulk primary carbonatite (bastnasite and calcite; delta O-18 = 5. 8 parts per thousand similar to 12.
WOS关键词	RARE-EARTH-ELEMENTS ; U-PB AGES ; WESTERN SICHUAN PROVINCE ; ENRICHED MANTLE SOURCE ; SOUTHWESTERN CHINA ; SW CHINA ; HYDROTHERMAL MOBILIZATION ; GEOCHEMICAL CONSTRAINTS ; ZONE CARBONATITES ; QINLING OROGEN
WOS研究方向	Geology
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000408702200002
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/62010]
专题	地质与地球物理研究所_其他部门
通讯作者	Liu Yan
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 2.Nanjing Univ, State Key Lab Mineral Deposit Res, Nanjing 210093, Jiangsu, Peoples R China 3.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China 4.China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China 5.Inst Reg Geol & Mineral Resources Survey Hebei Pr, Langfang 065000, Peoples R China 6.Guilin Univ Technol, Sch Earth Sci, Guilin 541004, Peoples R China
推荐引用方式 GB/T 7714	Liu Yan,Chen Chao,Shu XiaoChao,et al. The formation model of the carbonatite-syenite complex REE deposits in the east of Tibetan Plateau: A case study of Dalucao REE deposit[J]. ACTA PETROLOGICA SINICA,2017,33(7):1978-2000.
APA	Liu Yan.,Chen Chao.,Shu XiaoChao.,Guo DongXu.,Li ZiJing.,...&Jia YuHeng.(2017).The formation model of the carbonatite-syenite complex REE deposits in the east of Tibetan Plateau: A case study of Dalucao REE deposit.ACTA PETROLOGICA SINICA,33(7),1978-2000.
MLA	Liu Yan,et al."The formation model of the carbonatite-syenite complex REE deposits in the east of Tibetan Plateau: A case study of Dalucao REE deposit".ACTA PETROLOGICA SINICA 33.7(2017):1978-2000.