摘要
山西义兴寨金矿是五台山—恒山金矿集区内最为典型的金矿床,也是山西省最大的金矿床。近年来,在矿区河湾斑岩体的深部探矿过程中发现了一个大型蚀变斑岩型金矿体(>20 t Au)。然而,关于该蚀变斑岩金矿体的成因还缺乏相关的研究,因而制约了对该矿床深部及外围勘探工作的开展。本文通过对蚀变斑岩的锆石开展了LA–ICPMS原位的U–Pb同位素分析,结果表明蚀变石英斑岩的侵位时间为141±1 Ma,从而限定了蚀变斑岩金矿化的时间在131-141 Ma之间。对硫化物石英脉和蚀变斑岩型金矿石系统的元素地球化学分析结果表明两种类型矿石具有相似的特征,进而提出蚀变斑岩型金矿化与脉状金矿是同期成矿流体作用的结果。
Yixingzhai gold deposit in the Wutaishan Hengshan gold district is the most important and largest gold deposit in Shanxi Province. Recently, new altered-porphyry gold orebody （〉20t Au） has been found in the Hewan quartz porphyry. However, genesis and timing constraints on the altered-porphyry gold mineralization in this deposit are lacking. This fact severely hinders the gold exploration in deep and surround areas of the Yixingzhai deposit. In this paper, U Pb dating of zircon grains from the altered-porphyry was carried out by using laser ablation inductively coupled plasma mass spectrometry （LA ICPMS）. The zircon grains yielded the weighted mean 206pb/23sU dates of 141 ± 1 Ma, which is used to constrain the timing of altered- porphyry gold mineralization ranging from 131-141 Ma. Geochemical characteristics of the altered-porphyry gold ores are consistent with vein-type gold ores, indicating that the formation of altered-porphyry gold min- eralization was genetically related to the vein-type gold mineralization. Therefore, we proposed that both two type gold mineralization origin from the same hydrothermal fluid event.
作者
张立中
ZHANG Li-Zhong(Zijin Mining Group Co.Mineral Exploration Institute,Xiamen 361006,Fujian,China)
出处
《华南地质与矿产》
CAS
2018年第2期134-141,共8页
Geology and Mineral Resources of South China
基金
国家重点研发计划(No.2016YFC0600104)
国家自然科学基金项目(No.41325007)
关键词
蚀变斑岩型金矿
锆石U-Pb定年
元素地球化学
义兴寨金矿
altered -porphyry gold mineralization
zircon U Pb dating
element geochemistry
Yixingzhai gold deposit
