Characteristics of Isotopic Geochemistry and Metallogenesis of the Gala Gold Deposit in Ganzi-Litang Suture Zone, Western Sichuan Province, China
详细信息
- 责任者：Yan Ni (State Key Laboratory of Geological Process and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Zhang Jing
- 刊名：Acta Petrologica Sinica
- 出版年：2013
- 卷期：29(4)
- 关键词：金矿 ; gold ores ; 同位素地球化学 ; isotope geochemistry ; 四川 ; Sichuan Province
- 页码：p.1347-1357
- 图表：illus., 4 tables, 45 refs.
- 分类号：1001
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
The Gala gold deposit is located in the northern Ganzi-Litang suture zone. There is obvious ductile shear deformation in the ore district. The ore bodies are mainly hosted in the ophiolite mixite of Upper Triassic Qugasi Formation and controlled by the NW-trending faults. In this paper, we analyzed the H-O-C isotopic composition of the quartz and ore-forming fluid and S-Pb isotopic composition of the sulfides from different ores in the Gala gold deposit. The δ18OQ values changed from 15.60‰ to 18.38‰, and the δ18OH2O values vary between 8.24‰ and 9.89‰, with the δDH2O values ranging between -121.342‰ and -126.368‰. The δ13CCO2 values of ore fluids are between -11.3‰ and -2.1‰. The δ34S values range from -9.2‰ to -4.9‰, with peaks ranging from -7‰ to -5‰. The ores are rich in U-radiogenic Pb. The studies on isotope systematics indicate that the ore fluids forming the Gala gold deposit were probably initially sourced from a process of metamorphic devolatilization, and gradually mixed with meteoric water; the ore-forming elements were mainly derived from the wallrock. The available K-Ar and Rb-Sr ages indicate that the ore-forming process mainly took place in Late Yanshanian, during the transition geodynamic setting from collisional compression to extension in the collisional process of the Yidun arc orogen, Sanjiang region. The Gala deposit can be determined as an orogenic-type gold deposit.