| 摘要: |
| 爬立山铁矿位于老挝-越南长山铜金铁多金属构造岩浆成矿带中段,为一大型矽卡岩型磁铁矿床。通过对矿床地质特征、岩体产出特征分析,认为该铁矿成矿作用受区内二长花岗岩岩浆活动制约。本文对含矿二长花岗岩进行了岩相学和锆石SHRIMP U-Pb定年研究。所测锆石内部结构、阴极发光图像特征及Th/U比值的研究表明,二长花岗岩中的锆石为岩浆锆石。U-Th-Pb同位素分析结果显示岩体形成年龄为280.3±2.9Ma(MSWD=0.70)。结合区域构造演化及构造岩浆岩带形成的动力学机制,认为爬立山铁矿系早二叠世洋板俯冲背景下弧岩浆作用主导的产物,与长山带海西晚期大规模铜金铁矿同属于一个活动陆缘成矿系统。 |
| 关键词: 爬立山铁矿 二长花岗岩 SHRIMP U-Pb定年 老挝 东南亚 |
| DOI： |
| 附件 |
| 投稿时间：2013-06-06修订日期：2013-06-20 |
| 基金项目:中央地勘基金境外矿产资源风险勘查项目(NO．［2011］D3-03);中国地质调查局国土资源大调查项目(NO．1212011220907;NO．1212011120337) |
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| SHRIMP zircon U-Pb dating of the ore-forming monzogranite from the Phalek iron deposit, Vientiane, Laos and its geological implications |
| WANG Jiang-li, LIN Fang-cheng, ZHU Hua-ping, WANG Hong, SHI Mei-feng |
(1. Chinese Academy of Geological Sciences, Beijing 100037, China;
2. Chengdu Institute of Geology and Mineral Resources, Chengdu 610081, Sichuan, China) |
| Abstract: |
| The Phalek iron deposit is a large-sized skarn-type magnetite deposit in the central part of the Cu-Au-Fe polymetallic structural-magmatic metallogenic belt in the Trung Son zone at the border area of Laos and Vietnam. Judged from the geology and occurrence of ore bodies, the mineralization of the iron deposit is dominantly controlled by the magmatism of the monzogranite in the study area. The present paper focuses on the petrography and SHRIMP zircon U-Pb dating of the ore-bearing monzogranite. The integration of internal structures, cathodoluminescence images and Th/U ratios of the measured zircons shows that the zircons from the monzogranite are of magmatic origin. As indicated by the U-Th-Pb isotopic analysis, the ages of the ore-bearing monzogranite masses are dated at 280.3±2.9 Ma (MSWD=0.70). The regional tectonic evolution and dynamic mechanisms for the formation of the structural-magmatic zone have also disclosed that the Phalek iron deposit resulted from the arc magmatism during the subduction of the Early Permian oceanic plate, and are assigned to the same active epicontinental metallogenic system as the late Hercynian large-sized Cu-Au-Fe deposits in the Trung Son metallogenic belt. |
| Key words: PhaLek iron deposit monzogranite SHRIMP zircon U-Pb dating Laos Southeast Asia |
