西藏查藏错铜铅锌矿床成因:C-H-O-S-Pb同位素制约

Abstract

Chazangcuo Cu-Pb-Zn deposit,hosted by the Linzizong Group volcanic rocks in the west of Gangdese metallogenic belt,is a copper polymetallic deposit discovered in recent years.So far,the genesis of the deposit is still lack of clear under-standing.The results of C,H,O,S,Pb isotopic analysis show that theδ13 CV-PDB values range from -5.60‰ to -2.40‰,δDV-SMOW values range from -111.00‰ to -68.00‰,andδ18 OV-SMOW values range from -8.65‰ to 0.27‰,indicating that the ore-forming fluid mainly derived from the magma hydrothermal in the early time,however,with the mineralization continu-ing,the proportion of atmospheric precipitation gradually turned larger.δ34 SCDT values range from 0.50‰ to 2.50‰ and pos-sess the distribution characteristics of tower,indicating that the sulfur isotope derived from the single magma source.Lead iso-tope ratios are relatively stable and have largeμvalues (more than 9.58),possessing the characteristics of the upper crust lead. The lead isotope characteristics are similar to the ore sulfides from the deposits in the north subzone of Gangdese metallogenic belt,but obviously different from the lead isotope characteristics of volcanic rocks of Dianzhong Formation.Therefore,the au-thors infer that the source of ore-forming materials mainly came from the magmatic source of the upper crust.Combining with the geological characteristics of Chazangcuo deposit,and contrasting the typical magmatic hydrothermal vein-type deposit at home and abroad,the authors think that it belongs to the typical magmatic hydrothermal vein-type deposit.