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Geofluids
Volume 2017, Article ID 3107280, 21 pages
https://doi.org/10.1155/2017/3107280
Research Article

Origin and Evolution of the Ore-Forming Fluids in the Liyuan Gold Deposit, Central North China Craton: Constraints from Fluid Inclusions and H-O-C Isotopic Compositions

1State Key Laboratory of Geological Processes and Mineral Resources, Faculty of Earth Resources, Collaborative Innovation Center for Exploration of Strategic Mineral Resources, China University of Geosciences, Wuhan 430074, China
2School of Earth Sciences, East China University of Technology, Nanchang 330013, China
3State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China

Correspondence should be addressed to Shao-Yong Jiang; nc.ude.guc@gnaijyhs

Received 28 January 2017; Accepted 6 June 2017; Published 7 August 2017

Academic Editor: Paolo Fulignati

Copyright © 2017 Ying Ma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The Liyuan gold deposit is hosted within Archean basement metamorphic rocks and controlled by the NNE-trending faults in the central North China Craton. The ore-forming processes can be divided into three stages (early, middle, and late). Three types of primary fluid inclusions (FIs) are identified in the Liyuan, including pure carbonic, carbonic-aqueous, and aqueous inclusions. The primary FIs of three stages are mainly homogenized at temperatures of 318–408°C, 201–329°C, and 136–229°C, with salinities of 2.1–8.9, 0.5–12.4, and 0.4–6.3 wt.% NaCl equivalent, respectively. The main Au mineralization is related to the middle stage, and water-rock interaction caused rapid precipitation of gold in this stage. The initial ore-forming fluids were likely magmatic water or metamorphic fluid and mixed with meteoric water at later stages. Due to the lack of granite body at the present mining levels, we speculate that it was magmatic water that might have been exsolved from a concealed granite body at greater depth or it was metamorphic fluid that was directly transported from depth via deep faults. Based on all the available geological and geochemical evidence, we suggest that the Liyuan deposit belongs to orogenic gold deposit that located in the interior North China Craton.