贵州铝土矿基底地层特征及其与成矿的关系

目前对于贵州铝土矿含矿岩系基底地层特征及其与成矿关系有一些研究,但缺乏系统性.通过在对省内大量铝土矿床勘查和研究资料的分析,获得一些新的认识.该地区基底地层时空分布上,由南到北、由西到东逐渐变新,黔北主要为硅酸盐岩,但古喀斯特地貌不明显,黔中以碳酸盐岩为主且有显著古喀斯特地貌.基底地层在一定程度上提供了成矿物源,同时也控制了矿体形态.因基底岩性和古喀斯特地貌的不同,使得在铝土物质沉积阶段沉积分选方式有差异,同时导致铝土物质次生富集阶段地下水化学特性及动力系统的差异,使硅排铁作用强弱不同,这些因素都影响矿石类型和品位.

Characteristics of basement strata in bauxite deposits of Guizhou Province and their relationships to regional mineralization

So far there have been some studies on characteristics ore-bearing basement strata in bauxite deposits of Guizhou and their relationships to regional mineralization, but such work remains not systematic. Through the analysis to a large number of survey and research data about bauxite mines in Guizhou, we have obtained some new insights into this issue. On the temporal and spatial distribution of basement strata, there exists a trend that the strata become younger from south to north and from west to east. The basements of northern Guizhou are dominated by silicate rocks, while ancient karst did not develop well. Such strata of central Guizhou are mainly carbonate rocks with conspicuous ancient karst. These basement strata provided mineralization sources to some extent and controlled the features of ore-bodies at the same time. The differentiation between basements lithology and ancient karst geomorphology caused different depositing and sorting modes within deposition phases for aluminous matter, and meanwhile resulted in discrepancies in groundwater chemistry properties and kinetic systems in the secondary enrichment stage for aluminous substance which made silicon iron chelating effect strong or weak. All these factors could affect the types and grades of bauxite ores in this region.