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Physico‐chemical Conditions and Ore‐forming Process of the Zhilingtou Au‐Ag Deposit, Zhejiang
Author(s) -
Minghua Zheng,
Jianming Liu
Publication year - 1988
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/j.1755-6724.1988.mp1001006.x
Subject(s) - boiling , hydrothermal circulation , mineralization (soil science) , geology , pyrite , geochemistry , salinity , fluid inclusions , meteoric water , sulfur , dilatant , mineralogy , high pressure , chemistry , metallurgy , nitrogen , materials science , geotechnical engineering , thermodynamics , oceanography , physics , organic chemistry , seismology
The mineralization of the Zhilingtou Au‐Ag deposit occurred in a heated circulation system of infiltrated meteoric water during the Indosinian and early Yanshanian, at a temperature ranging from 350 to 160°°C and at a depth of less than 2 km. The ore‐forming solution was acidic, strongly oxidized, and poor in sulfur, with moderate Cl − activity and salinity. Au and Ag migrated in the forms of AuCl − 2 and AgCl − 2 , and then were concentrated and precipitated in a pressure‐relief, dilatant zone—a tenso‐shear fracture. Pressure relief and boiling were the major mechanism for unloading of the fluid. The hydrothermal fluid was injected intermittently, and its boiling was characterized by pulsation. The presence of high‐valence manganese might represent the auxiliary mechanism for remobilization of Au and Ag in the Chencai Group and for their entering into the hydrothermal fluid.