Dating Ore Deposit Using Garnet U–Pb Geochronology: Example from the Xinqiao Cu–S–Fe–Au Deposit, Eastern China

Author： Zhang Yu Shao Yongjun Zhang Rongqing Li Dengfeng Liu Zhongfa Chen Huayong

Publisher： MDPI

E-ISSN： 2075-163x|8|1|31-31

ISSN： 2075-163x

Source： Minerals, Vol.8, Iss.1, 2018-01, pp. : 31-31

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

The large Xinqiao Cu–S–Fe–Au deposit in the Tongling ore district, Eastern China, is characterized by a large-scale stratiform orebody, in which garnet is widely distributed as the main gangue mineral associated with mineralization. Xinqiao garnet can be divided into early (Grt1) and late (Grt2) generations based on extensive back-scattered electron (BSE) imaging observations. Laser ablation (LA)-ICP-MS trace element and U–Pb isotope composition analyses indicate that uranium occurs homogeneously within the Xinqiao garnet, and Grt1 and Grt2 have weighted average ²⁰⁷Pb-corrected ²⁰⁶Pb/²³⁸U ages of 137.0 ± 7.8 Ma (Mean standard weighted deviation (MSWD) = 4.9) and 129.6 ± 7.1 Ma (MSWD = 1.6), respectively, similar to the zircon U–Pb age (139.6 ± 1.5 Ma) of the Jitou intrusion. These garnet U–Pb ages, combined with the low MnO content and various Y/Ho ratios, suggest that the Xinqiao garnet is likely to have a magmatic hydrothermal replacement origin associated with the Jitou stock. Based on previous studies of the Xinqiao deposit, we infer that the Xinqiao stratiform orebody may have formed from the Early Cretaceous magmatic hydrothermal fluids associated with the Jitou stock, and may have been generated by the Early Cretaceous tectono-thermal event in Eastern China.