| 鄂西北碱性火山岩型铌矿床榍石矿物学及对铌富集机理的指示 |
| |
| 引用本文： | 苌笙任,苏建辉,秦志军,赵新福.鄂西北碱性火山岩型铌矿床榍石矿物学及对铌富集机理的指示[J].地球科学,2022,47(4):1316-1332. |
| |
| 作者姓名： | 苌笙任 苏建辉 秦志军 赵新福 |
| |
| 作者单位： | 1.中国地质大学资源学院，湖北武汉 430074 |
| |
| 基金项目： | 国家重点研发计划项目(No.2017YFC0602401)；;国家自然科学基金(No.41822203)； |
| |
| 摘 要： | 位于南秦岭武当地区的天宝铌矿床是我国典型的碱性火山岩型铌矿床,但其岩浆成因、演化及成矿机理等方面的研究十分薄弱.天宝碱性火山岩主要分为粗面质岩石和碱性玄武岩两大类,两者在空间上紧密共生.在详细的岩(矿)相学及榍石显微结构研究的基础上,利用LA-ICP-MS分析技术对天宝粗面质火山岩中的榍石进行原位U-Pb定年,并利用E...
|
| 关 键 词： | 鄂西北 碱性火山岩铌矿床 榍石矿物学 成岩成矿过程 矿床 |
| 收稿时间： | 2021-02-05 |
Titanite Mineralogy and Its Implications for Nb Enrichment Mechanism of Alkaline Volcanic-Rock Hosted Nb Deposit in NW Hubei Province |
| |
| Chang Shengren,Su Jianhui,Qin Zhijun,Zhao Xinfu.Titanite Mineralogy and Its Implications for Nb Enrichment Mechanism of Alkaline Volcanic-Rock Hosted Nb Deposit in NW Hubei Province[J].Earth Science-Journal of China University of Geosciences,2022,47(4):1316-1332. |
| |
| Authors: | Chang Shengren Su Jianhui Qin Zhijun Zhao Xinfu |
| |
| Abstract: | The Tianbao niobium deposit, located in the Wudang area of the South Qinling belt, is a typical alkaline volcanic-rock hosted Nb deposit in China. However, the research on the origin and evolution of alkaline magma as well as the enrichment mechanism of Nb is lacking. The alkaline volcanic rocks in Tianbao can be divided into trachyte series and alkaline basalt series, which are spatially associated. In this study, it presents detailed petrography observation combined with in-situ U-Pb dating of titanite by LA-ICP-MS, and in-situ element analyses of different types of titanite by EPMA, to reveal the magma evolution and the Nb enrichment processes. The trachyte rocks have titanite U-Pb age of 432.4±4.4 Ma(n=30, MSWD=2.4), which is consistent with the zircon U-Pb age of other trachytes, mafic dykes, and carbonatite-alkaline complexes in the South Qinling belt, indicating that the study area had large-scale alkaline magmatism activation in the Early Silurian. The titanite from both trachyte and alkaline basalt rock are of magmatic and detrital origins based on their occurrences and geochemical characteristics. Most magmatic titanite grains are euhedral and coarse, and have oscillating zoning, while some grains are present in the form of small particles around the titanite phenocrysts. They have lower Al contents and Al/Fe ratios compared to detrital titanites, which are typically fragmented. The magmatic titanites in the early basaltic rock have lower concentrations of Nb2O5 (< 0.47%), Na2O (< 0.05%) and REE2O3 (< 0.87%), but have a large variety of Al2O3+ Fe2O3 (0.80%-2.91%), indicating that the Nb content in the early basaltic magma is relatively low. The magmatic titanites in the trachyte are obviously enriched in Nb2O5 (0.19%-1.50%) and REE2O3 (0.02%-4.06%). Trachytes also contain fine-grained other Nb minerals such as pyrochlore, columbite, and aeschynite, indicating that the contents of Nb are significantly increased during magma fractionation from basalt to trachyte, and eventually lead to ore-grade mineralization in trachyte. |
| |
| Keywords: | |
| 本文献已被 万方数据 等数据库收录！ |
| 点击此处可从《地球科学》浏览原始摘要信息 |
|
点击此处可从《地球科学》下载全文 |
|
