Fluid Inclusions and Hydrogen, Oxygen, Sulfur Isotopes of Nuri Cu-W-Mo Deposit in the Southern Gangdese, Tibet

doi:10.1111/j.1751-3928.2011.00179.x

	Fluid Inclusions and Hydrogen, Oxygen, Sulfur Isotopes of Nuri Cu-W-Mo Deposit in the Southern Gangdese, Tibet
	Chen, Lei 1,2; Qin, Kezhang 1; Li, Jinxiang 1; Xiao, Bo 1,2; Li, Guangming 1; Zhao, Junxing 1,2; Fan, Xin 1,2
刊名	RESOURCE GEOLOGY
	2012
卷号	62 期号:1 页码:42-62
关键词	fluid inclusions hydrogen-oxygen isotope sulfur isotope Nuri skarn Cu-W-Mo deposit southern Gangdese Tibet
ISSN号	1344-1698
DOI	10.1111/j.1751-3928.2011.00179.x
文献子类	Article
英文摘要	The Nuri Cu-W-Mo deposit is located in the southern subzone of the Cenozoic Gangdese Cu-Mo metallogenic belt. The intrusive rocks exposed in the Nuri ore district consist of quartz diorite, granodiorite, monzogranite, granite porphyry, quartz diorite porphyrite and granodiorite porphyry, all of which intrude in the Cretaceous strata of the Bima Group. Owing to the intense metasomatism and hydrothermal alteration, carbonate rocks of the Bima Group form stratiform skarn and hornfels. The mineralization at the Nuri deposit is dominated by skarn, quartz vein and porphyry type. Ore minerals are chalcopyrite, pyrite, molybdenite, scheelite, bornite and tetrahedrite, etc. The oxidized orebodies contain malachite and covellite on the surface. The mineralization of the Nuri deposit is divided into skarn stage, retrograde stage, oxide stage, quartz-polymetallic sulfide stage and quartz-carbonate stage. Detailed petrographic observation on the fluid inclusions in garnet, scheelite and quartz from the different stages shows that there are four types of primary fluid inclusions: two-phase aqueous inclusions, daughter mineral-bearing multiphase inclusions, CO2-rich inclusions and single-phase inclusions. The homogenization temperature of the fluid inclusions are 280 degrees C386 degrees C (skarn stage), 200 degrees C340 degrees C (oxide stage), 140 degrees C375 degrees C (quartz-polymetallic sulfide stage) and 160 degrees C280 degrees C (quartz-carbonate stage), showing a temperature decreasing trend from the skarn stage to the quartz-carbonate stage. The salinity of the corresponding stages are 2.9%49.7 wt% (NaCl) equiv., 2.1%7.2 wt% (NaCl) equiv., 2.6%55.8 wt% (NaCl) equiv. and 1.2%15.3 wt% (NaCl) equiv., respectively. The analyses of CO2-rich inclusions suggest that the ore-forming pressures are 22.1 M Pa50.4 M Pa, corresponding to the depth of 0.9 km2.2 km. The Laser Raman spectrum of the inclusions shows the fluid compositions are dominated in H2O, with some CO2 and very little CH4, N2, etc. dD values of garnet are between -114.4% and -108.7% and d18OH2O between 5.9% and 6.7%; dD of scheelite range from -103.2% to -101.29% and d18OH2O values between 2.17% and 4.09%; dD of quartz between -110.2% and -92.5% and d18OH2O between -3.5% and 4.3%. The results indicate that the fluid came from a deep magmatic hydrothermal system, and the proportion of meteoric water increased during the migration of original fluid. The d34S values of sulfides, concentrated in a rage between -0.32% to 2.5%, show that the sulfur has a homogeneous source with characteristics of magmatic sulfur. The characters of fluid inclusions, combined with hydrogen-oxygen and sulfur isotopes data, show that the ore-forming fluids of the Nuri deposit formed by a relatively high temperature, high salinity fluid originated from magma, which mixed with low temperature, low salinity meteoric water during the evolution. The fluid flow through wall carbonate rocks resulted in the formation of layered skarn and generated CO2 or other gases. During the reaction, the ore-forming fluid boiled and produced fractures when the pressure exceeded the overburden pressure. Themeteoric water mixed with the ore-forming fluid along the fractures. The boiling changed the pressure and temperature, oxygen fugacity, physical and chemical conditions of the whole mineralization system. The escape of CO2 from the fluid by boiling resulted in scheelite precipitation. The fluid mixing and boiling reduced the solubility of metal sulfides and led the precipitation of chalcopyrite, molybdenite, pyrite and other sulfide.
WOS关键词	ORE-FORMING FLUIDS ; SKARN DEPOSIT ; ERTSBERG DISTRICT ; PORPHYRY COPPER ; MINES GASPE ; BIG GOSSAN ; AU ; EVOLUTION ; CHINA ; ORIGIN
WOS研究方向	Geology ; Mineralogy
语种	英语
出版者	WILEY-BLACKWELL
WOS记录号	WOS:000298591200004
资助机构	NSFC(40772066 ; NSFC(40772066 ; China Metallurgical Geology Bureau ; China Metallurgical Geology Bureau ; 41072059) ; 41072059) ; NSFC(40772066 ; NSFC(40772066 ; China Metallurgical Geology Bureau ; China Metallurgical Geology Bureau ; 41072059) ; 41072059) ; NSFC(40772066 ; NSFC(40772066 ; China Metallurgical Geology Bureau ; China Metallurgical Geology Bureau ; 41072059) ; 41072059) ; NSFC(40772066 ; NSFC(40772066 ; China Metallurgical Geology Bureau ; China Metallurgical Geology Bureau ; 41072059) ; 41072059)
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/84660]
专题	中国科学院地质与地球物理研究所
通讯作者	Qin, Kezhang
作者单位	1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Chinese Acad Sci, Grad Univ, Beijing, Peoples R China
推荐引用方式 GB/T 7714	Chen, Lei,Qin, Kezhang,Li, Jinxiang,et al. Fluid Inclusions and Hydrogen, Oxygen, Sulfur Isotopes of Nuri Cu-W-Mo Deposit in the Southern Gangdese, Tibet[J]. RESOURCE GEOLOGY,2012,62(1):42-62.
APA	Chen, Lei.,Qin, Kezhang.,Li, Jinxiang.,Xiao, Bo.,Li, Guangming.,...&Fan, Xin.(2012).Fluid Inclusions and Hydrogen, Oxygen, Sulfur Isotopes of Nuri Cu-W-Mo Deposit in the Southern Gangdese, Tibet.RESOURCE GEOLOGY,62(1),42-62.
MLA	Chen, Lei,et al."Fluid Inclusions and Hydrogen, Oxygen, Sulfur Isotopes of Nuri Cu-W-Mo Deposit in the Southern Gangdese, Tibet".RESOURCE GEOLOGY 62.1(2012):42-62.