Incursion of meteoric water triggers molybdenite precipitation in porphyry Mo deposits: A case study of the Chalukou giant Mo deposit

doi:10.1016/j.oregeorev.2019.04.011

CORC > 地质与地球物理研究所 > 中国科学院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

	Incursion of meteoric water triggers molybdenite precipitation in porphyry Mo deposits: A case study of the Chalukou giant Mo deposit
	Li, Zhen-Zhen 1,2; Qin, Ke-Zhang 1,2,3; Li, Guang-Ming 1,2; Jin, Lu-Ying 1,2; Song, Guo-Xue 3; Han, Ri 1,2,3
刊名	ORE GEOLOGY REVIEWS
	2019-06-01
卷号	109 页码:144-162
关键词	Chalukou Porphyry Mo deposit Quartz Oxygen isotope Meteoric water Metal precipitation
ISSN号	0169-1368
DOI	10.1016/j.oregeorev.2019.04.011
英文摘要	There has been a long-term debate about the timing of the incursion of meteoric water into porphyry systems and whether it plays an important role in ore precipitation. To evaluate the role of meteoric water in the mineralization in porphyry Mo deposits, typical hydrothermal veins of different stages from the Chalukou giant porphyry Mo deposit are selected for combined scanning electron microscope cathodoluminescence (SEM-CL), fluid inclusion microthermometry and high-resolution secondary ion mass spectroscopy (SIMS) oxygen isotope analyses. Multiple generations of quartz are identified in almost all of the veins. The barren quartz veins and quartz-magnetite veins of the early Mo mineralization stage are dominated by granular CL-bright quartz (EMQ1), which usually shows dissolution and re-deposition textures and are overprinted by CL-dark quartz (EMQ2)-filled healed fractures. The molybdenite precipitation in the quartz-molybdenite veins of the main Mo mineralization stage is synchronous with small volumes (< 15%) of CL-dark quartz (MMQ2) and postdates the large volume (> 85%) of CL-bright quartz (MMQ1). Similar to the quartz-molybdenite veins, the precipitation of pyrite in the quartz-pyrite veins during the transitional stage and sphalerite in the quartz-sphalerite-pyrite veins during the Zn-Pb mineralization stage are also directly associated with CL-dark quartz (TSQ2, ZPQ2). The SIMS oxygen isotopic values of EMQ1 and MMQ1 fall into the range of 5.42-9.79%o with calculated equilibrium fluid compositions of 2.07-6.45%0, indicating a magma-dominated fluid composition, whereas MMQ2, TSQ2 and ZPQ2 have very low oxygen isotopic values from -4.68 to -4.29 parts per thousand with corresponding fluid compositions of -13.64 to -5.94 parts per thousand, implying that the fluid formed by the mixing of magmatic water and a large proportion of meteoric water. The contrasting SEM-CL features and oxygen isotopic compositions of the two generations of quartz in the quartz-molybdenite veins demonstrate that the incursion of meteoric water into the hydrothermal system occurred earlier than the molybdenite precipitation. Based on these results and the crosscutting relationships and spatial distribution of the veins, we reconstructed the quartz evolutionary sequence during the vein development process. After the early precipitation of barren quartz, the reduction in fluid pressure from lithostatic to hydrostatic conditions allowed the incursion of convecting cool meteoric water into the relatively hot hydrothermal system, and the temperature of the evolved Mo-rich fluid decreased rapidly from > 500 degrees C to < 400 degrees C, leading to concentrated molybdenite precipitation with small volumes of quartz. Fluid cooling resulting from the incursion of meteoric water may have played a greater role in the metal precipitation in the Chalukou Mo deposit than wallrock interactions and fluid boiling. Moreover, this process may have also occurred in other porphyry Mo deposits.
资助项目	National Key R&D Program of China[2017YFC0601306] ; National Natural Science Foundation of China[41502094] ; National Natural Science Foundation of China[41390444]
WOS关键词	NE CHINA IMPLICATIONS ; CU-AU DEPOSIT ; MAGMATIC-HYDROTHERMAL SYSTEM ; OXYGEN ISOTOPE EVIDENCE ; RE-OS GEOCHRONOLOGY ; GREAT XINGAN RANGE ; STABLE-ISOTOPE ; FLUID INCLUSIONS ; INNER-MONGOLIA ; U-PB
WOS研究方向	Geology ; Mineralogy ; Mining & Mineral Processing
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000472686500009
资助机构	National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Key R&D Program of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; National Natural Science Foundation of China
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/92681]
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
通讯作者	Li, Zhen-Zhen; Qin, Ke-Zhang
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Chinese Acad Sci, Inst Earth Sci, Beijing 100029, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Li, Zhen-Zhen,Qin, Ke-Zhang,Li, Guang-Ming,et al. Incursion of meteoric water triggers molybdenite precipitation in porphyry Mo deposits: A case study of the Chalukou giant Mo deposit[J]. ORE GEOLOGY REVIEWS,2019,109:144-162.
APA	Li, Zhen-Zhen,Qin, Ke-Zhang,Li, Guang-Ming,Jin, Lu-Ying,Song, Guo-Xue,&Han, Ri.(2019).Incursion of meteoric water triggers molybdenite precipitation in porphyry Mo deposits: A case study of the Chalukou giant Mo deposit.ORE GEOLOGY REVIEWS,109,144-162.
MLA	Li, Zhen-Zhen,et al."Incursion of meteoric water triggers molybdenite precipitation in porphyry Mo deposits: A case study of the Chalukou giant Mo deposit".ORE GEOLOGY REVIEWS 109(2019):144-162.