文献类型：期刊文献

中文题名：黔北务-正-道地区铝土矿床的矿物学特征

英文题名：Mineralogic Characteristics of the Bauxite Deposit in the Wuchuan-Zheng'an-Daozhen Area,Northern Guizhou Province,China

作者：金中国 周家喜 黄智龙 谢樨 谷静 刘玲 向贤礼 邹林 韩英 代龙省 郭松

第一作者：金中国

机构：[1]贵州省有色金属和核工业地质勘查局;[2]中国科学院地球化学研究所,矿床地球化学国家重点实验室;[3]贵州理工学院;[4]有色金属矿产地质调查中心;[5]昆明理工大学国土资源工程学院

第一机构：贵州省有色金属和核工业地质勘查局,贵阳550005

年份：2015

卷号：89

期号：8

起止页码：1458-1470

中文期刊名：地质学报

外文期刊名：Acta Geologica Sinica

收录：CSTPCD;;Scopus;北大核心:【北大核心2014】；CSCD:【CSCD2015_2016】；

基金：贵州省公益性、基础性研究项目(编号:[2007]-172);国家十二五科技支撑项目(编号:2011BAB04B04)资助的成果

语种：中文

中文关键词：铝土矿;矿物学特征;沉积分异;成因机理;黔北务-正-道铝土矿集区

外文关键词：bauxite; mineralogic characteristics; sedimentary differentiation; formation mechanismWuchuan-Zhen＇an-Daozhen A1 metallogenic district; Northern Guizhou province

摘要：黔北务-正-道铝土矿集区为黔中—渝南铝土矿成矿带的重要组成部分,是贵州省主要的铝土矿成矿区之一。含矿岩系为中二叠统梁山组,矿床成因属古风化壳沉积型。矿石化学成分分析显示,土状、碎屑状铝土矿中Al_2O_3含量较高,Al_2O_3/SiO_2值大,质量好,而豆鲕状、致密块状铝土矿中Al_2O_3含量较低,Al_2O_3/SiO_2值小,质量较差。显微观察、粉晶衍射和电子探针分析表明,铝土矿石中主要矿物为一水硬铝石、勃姆石和粘土矿物,其中一水硬铝石多为短柱、半自形—自形晶体,呈集合体分布,粘土矿物以高岭石为主,呈孤岛、残留环状产出,其次见伊利石、蒙托石、绿泥石等,副矿物有黄铁矿、磁铁矿、长石、石英、金红石、锆石、锐钛矿、方解石和白云石等。铝土岩中主要矿物为粘土矿物,以高岭石为主,其它矿物和铝土矿相似。铝土矿石的主要元素Al_2O_3、SiO_2、TFe_2O_3和TiO_2含量之和大于83%,烧失量小于14%,而铝土岩的Al_2O_3、SiO_2、TFe_2O_3和TiO_2含量之和小于80%,烧失量大于15%。可见铝土矿和铝土岩在主要矿物组成和主要组分总量上具有明显差异。结合以往研究资料,本文解析铝土矿形成过程为韩家店组砂页岩(成矿母岩)在适宜的气候条件下,经风化、淋滤等作用,形成富集Al、Ti等惰性元素的风化残积物和以高岭石为主的粘土矿物,随后被迁移、搬运至河湖盆地环境中,在沉积分异过程中粘土矿物不断脱硅、去铁、富铝,形成铝土岩层,经埋深压实、成岩成矿作用后进一步脱硅、去铁、富铝,最终在中二叠世形成以一水硬铝石为主的铝土矿工业矿体。
The Wuchuan-Zhen＇ an-Daozhen A1 metallogenic district, northern Guizhou province, located in southern Chongqing-central Guizhou bauxite metallogenic belt, is one of the major bauxite regions in Guizhou province. The bauxite-bearing rock series is the Middle Permian Liangshan Formation and the ore genesis of the bauxite belongs to paleo-weathering crust sedimentary type. The results of the chemical compositions analysis show that the Al2O3 contents and Ai/Si ratios of the earthy, clastic bauxite is higher than those of the oolitic, dense massive bauxite. Based on the microscopic observation, powder diffraction and electron microprobe analysis, the major minerals of bauxite ores are the diaspore, boehmite, and clay minerals, of which the diaspore is aggregated distribution and shows a short column, subhedral euhedral crystal form, the clay mineral is mainly kaolinite and shows present island and residual cyclic occurrences, the other clay minerals include illite, montmorillonite and chlorite. Other minerals consist of pyrite minerals, magnetite, feldspar, quartz, rutile, zircon, anatase, calcite and dolomite. The main minerals in bauxite rocks are clay minerals, which are mainly kaolinite, and other minerals are similar with the bauxite. The content of Al2O3, SiO2, TiFe2O3 and TiO2 in bauxite ores is higher than 83% and the content of the loss on ignition is less than 14%, while the content of Al2O3, SiO2, TiFe2O3 and TiO2 in bauxite rocks less than 80% and the content of loss on ignition greater than 15%. This indicates that the bauxite ores is significantly different from bauxite rocks. Combined with previous studies, this paper suggests the formation process of bauxite ores is that under the suitable climatic conditions, the sandshale of the Lower-Middle Silurian Hanjiadian Formation （the ore-forming mother rocks） was weathering and leaching, then formed weathering residues and clay minerals （mainly kaolinite） which enriched in Al, Ti and other inert elements. After migrating to lakes basin environment, the clay minerals continually lost silicon and iron, enriched in aluminum and formed bauxite rocks. Finally, under the processes of deep buried compaction, diagenesis and mineralization, these clay minerals further lost silicon and iron,enriched in aluminum, the industrial bauxite ores formed in the Middle Permian.