Tin-polymetallic sulfide deposits in the eastern part of the Dachang tin field (South China) and the role of black shales in their origin

doi:10.1007/s00126-002-0269-4

	Tin-polymetallic sulfide deposits in the eastern part of the Dachang tin field (South China) and the role of black shales in their origin
	Pasava, J ; Kribek, B ; Dobes, P ; Vavrin, I ; Zak, K ; Fan, DL ; Tao, Z ; Boiron, MC
刊名	MINERALIUM DEPOSITA
	2003
卷号	38 期号:1 页码:39-66
关键词	black shale China Dachang stable isotopes tin-polymetallic ores
ISSN号	0026-4598
DOI	10.1007/s00126-002-0269-4
文献子类	Article
英文摘要	The Dafulou and Huile vein and stratabound cassiterite-sulfide deposits and sheeted ore veins at the Kangma cassiterite-sulfide deposit are located in the eastern part of the Dachang tin field. These deposits are hosted in a sedimentary sequence containing significant concentrations of organic matter in the form of Lower Devonian calcareous black shales and hornfels. These rocks together with the younger intrusion of Longxianggai granite (91 +/- 2 Ma) actively participated in the formation of Sn-polymetallic deposits. The following three major stages have been distinguished in stratiform and vein-type orebodies at Dafulou, Huile and Kangma: stage I (cassiterite, pyrrhotite, arsenopyrite, tourmaline, carbonate), stage II - main sulfide stage (quartz, cassiterite, arsenopyrite, pyrrhotite, sphalerite, stannite, pyrite, carbonates) and stage III (native Bi, galena, electrum, sulfosalts). Stage IV (post-ore), recognized at Huile is represented by barren carbonates and zeolites. Whole rock geochemistry has revealed that at Dafulou, Bi and Cu correlate strongly with S, whereas V and Pb correlate well with C-org (organic carbon). The similar distribution patterns of selected elements in average slightly mineralized low-Ca black shales indicate a fluid composition similar for all deposits studied. Studies of graphitization of the organic matter in black shales adjacent to orebodies indicate that d((002)) and FWHM (full width in half maximum)/peak height values gradually decrease in the following sequence: Dafulou deposit --> Kangma deposit --> Huile deposit. The pyrolysate of wall rocks at the Dafulou deposit is relatively enriched in asphaltenes and maltenes (55.6-72.0% of the pyrolysate) comparable with pyrolysate obtained from more distal black shales (19.2-28.5%). Typical GC-MS spectra of pyrolysate from distal black shales are dominated by alkanes in the n-C15 to n-C25 range, aromatic molecules being represented mostly by alkyl-naphthalenes. In contrast, only traces of aliphatic hydrocarbons in the n-C14 to n-C18 range and elemental sulfur were identified in pyrolysates from pyrrhotitized wall rocks. The earliest fluid inclusions of the studied system occur in the quartz-tourmaline-cassiterite assemblage of stage I at Dafulou. These inclusions are H2O-CO2-CH4-rich, with 10 to 20 vol% of aqueous phase. P-T conditions of the trapping of inclusions are estimated to be up to 400 degreesC and 1.3 to 2.0 kbar (between 5.0 and 7.5 km under lithostatic pressure). In contrast, the presence of a low density gaseous CO2-CH4 phase indicates relatively low pressures during the formation of the breccia-type quartz-calcite-cassiterite-sulfide mineralization (stage II), when P-T conditions probably reached approx. 380 to 400 degreesC and 0.6 kbar (up to 6 km under hydrostatic pressure). Fluid inclusion data and oxygen isotope thermometry indicate that cassiterite-sulfide ores of the main sulfide stage (stage II) formed from aqueouscarbonic fluid (CO2/CH4 = approximate to 10) at temperatures of up to 390 degreesC at Dafulou and in a temperature range of 250 to 360 degreesC at Huile and 260 to 370 degreesC at Kangma. The delta(34)S values of sulfides from Dafulou range mostly between -1 and -6parts per thousand, whereas sulfides from the Kangma and Huile deposits are characterized by more negative delta(34)S values (between -8 and -11parts per thousand, and between -9 and -12parts per thousand.
WOS关键词	CARBON ISOTOPE COMPOSITION ; REPUBLIC-OF-CHINA ; FLUID INCLUSIONS ; SYSTEM ; METALLOGENY ; GUANGXI ; OXYGEN ; FRACTIONATION ; TEMPERATURES ; CASSITERITE
WOS研究方向	Geochemistry & Geophysics ; Mineralogy
语种	英语
出版者	SPRINGER-VERLAG
WOS记录号	WOS:000180493900003
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/78126]
专题	中国科学院地质与地球物理研究所
通讯作者	Pasava, J
作者单位	1.Czech Geol Survey, Prague 11821 1, Czech Republic 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 3.Univ Henri Poincare, UMR GR2, F-54506 Vandoeuvre Les Nancy, France 4.Univ Henri Poincare, CREGU, F-54506 Vandoeuvre Les Nancy, France
推荐引用方式 GB/T 7714	Pasava, J,Kribek, B,Dobes, P,et al. Tin-polymetallic sulfide deposits in the eastern part of the Dachang tin field (South China) and the role of black shales in their origin[J]. MINERALIUM DEPOSITA,2003,38(1):39-66.
APA	Pasava, J.,Kribek, B.,Dobes, P.,Vavrin, I.,Zak, K.,...&Boiron, MC.(2003).Tin-polymetallic sulfide deposits in the eastern part of the Dachang tin field (South China) and the role of black shales in their origin.MINERALIUM DEPOSITA,38(1),39-66.
MLA	Pasava, J,et al."Tin-polymetallic sulfide deposits in the eastern part of the Dachang tin field (South China) and the role of black shales in their origin".MINERALIUM DEPOSITA 38.1(2003):39-66.