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U‐Pb SHRIMP Dating of Zircon from Quartz Veins of the Yangshan Gold Deposit in Gansu Province and Its Geological Significance
Author(s) -
Jinzhong QI,
Shisong YUAN,
Zhijie LIU,
Dunyi LIU,
Yanbin WANG,
Zhihong LI,
Junhua GUO,
Bin SUN
Publication year - 2004
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.1755-6724.2004.tb00152.x
Subject(s) - zircon , geology , geochemistry , quartz , hydrothermal circulation , vein , mineralization (soil science) , mineralogy , cretaceous , paleontology , soil water , psychology , psychiatry , soil science
The Yangshan gold deposit is a super‐large fine‐grained disseminated gold deposit located in southern Gansu Province. Its metallogenic age has been determined by using the cathodoluminescence image and ion probe U‐Pb dating techniques. It is found that zircons from quartz veinlet of the fine‐grained disseminated gold ore show characters of magmatic origin with prism idiomorphism, oscillatory zoning and dominant Th/U ratios of 0.5–1.5. Three main populations of zircons are obtained, giving average 206 Pb/ 238 U ages of 197.6±1.7 Ma, 126.9±3.2 Ma and 51.2±1.3 Ma respectively. The first age corresponds to the K‐Ar age of the plagiogranite dike, while the latter two ages indicate that buried Cretaceous and Tertiary intrusives exist in the orefield, suggesting that the Yangshan gold deposit was genetically related to the three magmatic hydrothermal activities. By contrast, zircons from coarse gold‐bearing quartz vein in the mining area are much older than the host rock, indicating that the vein was formed earlier and was not contaminated by later magmatic fluids. It is concluded that the coupling of multiperiodic hydrothermal activities in the mining area has contributed a lot to mineralization of the Yangshan gold deposit.