| 冈底斯东段羌堆铜钼矿床年代学、矽卡岩石榴
石成分及其意义 |
| 投稿时间：2010-09-18 修订日期：2010-11-06 点此下载全文 |
| 引用本文：李金祥.冈底斯东段羌堆铜钼矿床年代学、矽卡岩石榴
石成分及其意义[J].地质与勘探,2011,47(1):11-19 |
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| 基金项目:本文受中国冶金地质总局“冈底斯东段南部矽卡岩-斑岩Cu-Au-Mo 矿床成矿模式及成矿条件综合研究冶和国家自然科学基
金(编号:40772066)资助。 |
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| 中文摘要:[摘要]羌堆铜钼矿床是在冈底斯成矿带东段新发现的一处斑岩-矽卡岩型矿床。二长花岗斑岩
是该矿床的主要成矿斑岩体,本文用精确的LA-ICP-MS 锆石U-Pb 定年获得其年龄为16. 7依0. 9Ma,确
定该矿床为中新世成矿,与冈底斯成矿带上驱龙、甲马矿床为同一期成矿事件。对该矿床矽卡岩中石榴
石系统研究表明,早期矽卡岩主要以钙铝榴石为主,晚期以钙铁榴石为主;并暗示相应的成矿流体温度
和盐度逐渐降低,而氧逸度和pH 逐渐升高。另外,部分石榴石含有高含量的F,暗示成矿流体可能富含
一定的F。同时,矽卡岩中发育石英-黄铜矿-辉钼矿等脉系,暗示有类似于斑岩型的后期热液活动叠
加,以及钻孔中发现岩枝状产出的成矿二长花岗斑岩,综合显示下部有斑岩型矿床找矿前景。 |
| 中文关键词:LA-ICP-MS 锆石U-Pb 定年 羌堆铜钼矿床 石榴石成分 中冈底斯东段 |
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| Zircon U-Pb Geochronology and Garnet Composition of the Qiangdui Cu-Mo Depositin the Eastern Section of Gangdese and Their Significances |
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| Abstract:Abstract:The Qiangdui Cu-Mo deposit is a newly discovered porphyry-skarn type deposit in the eastern section of the Gangdese metallogenetic belt.
Argillic monzogranite porphyry is the major ore-forming rock. In this study, ore-forming monzogranite porphyry yields the precise LA-ICP-MS zircon U
-Pb age of 16. 7依0. 9Ma, confirming this deposit formed in the Miocene. This age indicates that the Qiangdui Cu-Mo deposit belongs to the same metallo鄄
genetic event as the Qulong and Tinggong Cu-Mo deposits, Jiama Cu-Pb-Zn deposit in the central Gangdese belt. Additionally, the systematic researches
of garnets in the skarn indicate the early-stage skarn is dominated by grossular, and the late-stage skarn is dominated by andradite. This observation also
suggests that the salinity and temperature of ore-forming fluid gradually decrease, while oxygen fugacity and pH gradually increase. Besides, partial gar鄄
nets show high content of F, possibly suggesting the ore-forming fluids have a certain amount of F. It is worth noting that the quartz-chalcopyrite-molyb鄄
denite veinlets occur in the skarn, implying they may be superposed by the later hydrothermal activity similar to the porphyry type deposit. Ore-forming
monzogranite porphyry apophyses appear in the drill holes. These observations may indicate that there is a prospecting potential of the porphyry type miner鄄
alization in the deep subsurface. |
| keywords:LA-ICP-MS zircon U-Pb age, garnet, Qiangdui Cu-Mo deposit, eastern section of Gangdese |
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