eCite Digital Repository

Geology and fluid evolution of the Wangfeng orogenic-type gold deposit, Western Tian Shan, China

Citation

Zhang, L and Chen, Huayong and Chen, Y and Qin, Y and Liu, C and Zheng, Y and Jansen, Nicholas H, Geology and fluid evolution of the Wangfeng orogenic-type gold deposit, Western Tian Shan, China, Ore Geology Reviews, 49, (December) pp. 85-95. ISSN 0169-1368 (2012) [Refereed Article]

Copyright Statement

Copyright 2012 Elsevier B.V.

DOI: doi:10.1016/j.oregeorev.2012.09.002

Abstract

The Wangfeng gold deposit is located in Western Tian Shan and the central section of the Central Asian Orogenic Belt (CAOB). The deposit is mainly hosted in Precambrian metamorphic rocks and Caledonian granites and is structurally controlled by the Shenglidaban ductile shear zone. The gold orebodies consist of gold-bearing quartz veins and altered mylonite. The mineralization can be divided into three stages: quartz-pyrite veins in the early stage, sulfide-quartz veins in the middle stage, and quartz-carbonate veins or veinlets in the late stage. Ore minerals and native gold mainly formed in the middle stage. Four types of fluid inclusions were identified based on petrography and laser Raman spectroscopy: CO2-H2O inclusions (C-type), pure CO2 inclusions (PC-type), NaCl-H2O inclusions (W-type), and daughter mineral-bearing inclusions (S-type). The early-stage quartz contains only primary CO2-H2O fluid inclusions with salinities of 1.62 to 8.03wt.% NaCl equivalent, bulk densities of 0.73 to 0.89g/cm3, and homogenization temperatures of 256°C-390°C. Vapor bubbles are composed of CO2. The middle-stage quartz contains all four types of fluid inclusions, of which the CO2-H2O and NaCl-H2O types yield homogenization temperatures of 210°C-340°C and 230°C-300°C, respectively. The CO2-H2O fluid inclusions have salinities of 0.83 to 9.59wt.% NaCl equivalent and bulk densities of 0.77 to 0.95g/cm3, with vapor bubbles composed of CO2, CH4, and N2. Fluid inclusions in the late-stage quartz are NaCl-H2O solution with low salinities (0.35-3.87wt.% NaCl equivalent) and low homogenization temperatures (122°C-214°C). The coexistence of inclusions of these four types in middle-stage quartz suggests that fluid boiling occurred in the middle-stage mineralization. Trapping pressures estimated from CO2-H2O inclusions are 110-300MPa and 90-250MPa for the early and middle stages, respectively, suggesting that gold mineralization mainly occurred at depths of about 10km. In general, the Wangfeng gold deposit originated from a metamorphic fluid system characterized by low salinity, low density, and enrichment of CO2. Depressurized fluid boiling caused gold precipitation. Given the regional geology, ore geology, fluid-inclusion features, and ore-forming age, the Wangfeng gold deposit can be classified as a hypozonal orogenic gold deposit. © 2012 Elsevier B.V.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Ore Deposit Petrology
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Mineral Exploration
Objective Field:Precious (Noble) Metal Ore Exploration
Author:Chen, Huayong (Dr Huayong Chen)
Author:Jansen, Nicholas H (Dr Nic Jansen)
ID Code:82533
Year Published:2012
Web of Science® Times Cited:22
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2013-02-06
Last Modified:2013-04-23
Downloads:0

Repository Staff Only: item control page