黔北后槽下石炭统含铝岩系的粘土矿物

Clay Minerals in Aluminiferous Rock System of Lower Carboniferous in Houcao,North Guizhou

为揭示黔北下石炭统含铝岩系的沉积环境,本文利用贵州遵义县后槽TC718剖面系统试样的粘土矿物进行X-射线衍射测试及特征分析。含铝岩系粘土岩与下伏桐梓组粘土页岩在矿物组合和成分上均有明显的差异,水云母的结晶度指数、开形指数在剖面纵向上有三个变化拐点:一是含铝岩系与下伏桐梓组粘土页岩分界处;二是含铝岩系上、下段的接触带;三是含铝岩系顶部含炭质粘土岩出现的临界面。其变化特征表明,本区下石炭统含铝岩系粘土岩段为海相或海陆过渡相,铝质岩段为残积-坡积相,顶部为大陆湖沼相;下奥陶统桐梓组页岩段为海相。

In order to reveal the sedimentary environment around aluminiferous rock system of lower Car- boniferous, this paper takes clay minerals of the Houcao TC718 profile in Zunyi County, Guizhou as the sample for X-ray diffraction test and the characteristics analysis. Clay rocks of aluminiferous rock system are obviously different from clay shale of underlying Tungtzu group in the mineral comp, ounding and component. There are three changes in inflexion of the crystallization index, the open form index of hydromica in vertical profile. One is at the boundary of aluminiferous rock system and clay shale of underlying Tungtzu group; the second is the contact zone of the higher section and the lower section of aluminiferous rock system; the Third is the interface where carbonaceous clay rocks appear at the top of aluminiferous rock system. Changes in its characteristics indicate that in the area clay section in aluminiferous rock system of lower carboniferous is marine facies or marine - continental transitional facies, the aluminiferous rock section is the eluvial - sloping facies, the top is continental lacustrine bog facies, and shale section of Tungstu group of the lower Ordovician is marine facies.