白云鄂博西矿火山岩岩石学特征

Petrological Characteristics of the Volcanic Rocks in the West Mine of Bayan Obo Deposit

自1927年丁道衡教授发现白云鄂博铁矿迄今已近90年。该矿床不仅仅是铁矿,而成为铌-稀土多金属矿床,其中稀土储量已成为世界最大的稀土矿床。国内外许多地质专家进行了多次考察和研究。曾有人预测矿区应有火山岩存在。直到1982年笔者才在西矿发现了火山岩。这些火山岩赋存于铁矿体附近的板岩中。它们是中酸性火山岩系列。包括英安质角砾凝灰熔岩、英安质熔结角砾岩和英安岩。这些火山岩具斑状构造,基质为隐晶质凝灰构造。英安岩基质为微晶结构。长石和石英斑晶微裂隙密布,石英有很好熔蚀的港湾结构,长石发育次生边,还见到火山玻璃及其碎屑。

It has been 90 years since Prof.Ding Daoheng found the Bayan Obo iron ore in 1927.Follow-up research and production show that the deposit is not just an iron ore,but world＇s largest rare earth and niobium deposit.Many geological experts both home and abroad have conducted numerous investigation and research.And volcanic rocks had been predicted to occur in this area.It was not until 1982 that the authors found volcanic rocks in the west mine of this area,which occur mainly in the slate surrounding iron orebodies.They are mainly composed of intermediate or acidic volcanic rock series,including dacitic breccia tuff,dacitic fused breccia,and dacite.The volcanic rocks are characterized by porphyry structure and aphanitic tuff texture.The dacite is microcrystalline structure,while feldspar and quartz phenocrysts are of well-developed microcracks.The quartz shows a harbor structure with good ablation.Secondary sides,volcanic glass and its debris also occur in the feldspar.