黔北铝土矿重矿物组合特征及地质意义

Characteristics and geological significance of heavy mineral assemblages in bauxite of northern Guizhou

对黔北地区4件铝土矿样品和6件铝土矿底板样品进行重矿物筛选分析。结果表明:黔北务正道地区铝土矿重矿物以风化碎屑、锆石、黄铁矿、褐铁矿、锐钛矿为主;黔北遵义地区铝土矿重矿物以白钛石、锆石、金红石、锐钛矿和风化碎屑为主;黔北地区铝土矿重矿物组合特征与下伏底板地层重矿物组合面貌基本相似,但铝土矿中含有部分稳定重矿物未在下伏地层中发现,表明黔北铝土矿由多种母岩提供成矿物质;黔北遵义地区黑色矿石中有机质含量高,形成酸性环境使铁向下迁移最终形成黄铁矿;黑色矿石同样经历了氧化淋滤作用,但其成矿机制与浅灰色铝土矿有一定区别,黑色铝土矿的成矿环境酸性强于浅灰色铝土矿。

Four samples of bauxite and six samples from the bottom plate were taken in northern Guizhou area for heavy mineral screening analysis.The heavy minerals of the WZD bauxite of northern Guizhou are mainly weathering debris,zircon,pyrite,limonite and anatase.The heavy mineral combination of the Zunyi bauxite of northern Guizhou is mainly composed of white titanium,weathering debris,zircon,rutile,anatase and weathering debris.The characteristics of heavy mineral assemblages in the bauxite of northern Guizhou are similar to those of the underlying stratum,but some heavy minerals in bauxite are not found in the underlying stratum,indicating that the mineralization material of the bauxite of northern Guizhou is provided by various parent rocks.The black ore in the Zunyi area of northern Guizhou has a high content of organic matter.The acidic environment causes the iron to migrate downwards to form pyrite.The black ore also undergoes oxidative leaching,but its ore-forming mechanism is different from that of light-gray bauxite.The ore-forming environment of black bauxite is more acidic than that of light-gray bauxite.