广西平果、贵州清镇沉积型铝土矿结构特征与沉积环境对比

Contrast of Structure Characteristics and Sedimentary Environment of Sedimentary Bauxite Deposit in Pingguo Guangxi and Qingzhen Guizhou

不同成因的铝土矿具有不同的结构特征,通过铝土矿的结构特征可以进一步推断其成因及沉积环境。通过对广西平果县太平镇、贵州清镇市站街镇大院两个地区的沉积型铝土矿野外及实验室观察分析认为:平果铝土矿中具鲕豆状结构的矿石少,多为碎屑结构、胶状结构,颗粒大小相差较大,分选差,且颗粒的含量较低,指示铝土矿就近沉积的特点,推断其沉积环境为滨海沼泽或泻湖;清镇铝土矿主要由鲕粒构成且具有完整的鲕粒及豆粒结构,颗粒的含量高,磨圆好,分选好,伴有少量碎屑颗粒组成的铝土矿,指示铝土矿经过较长距离搬运,沉积至水体能量高,扰动强烈的沉积区,为滨浅海沉积环境。

Different genesis of bauxite deposit has different structure characteristic. Based on the structure char- acteristics analysis of the bauxite, bauxite deposit genesis and sedimentary environment can discuss, there is a big difference between the Pingguo and the Qingzhen sedimentary bauxite ore structure： Oolite bean structure is less, more elastic structure and colloidal structure is common, grain size is uneven, permeability is poor, indicating bauxite deposits ore field is control nearby provenance, sedimentary environment is coastal marshes and lagoon, in Pingguo bauxite deposit; However, in Qingzhen bauxite is mainly composed of oolite bean structure, also visible is mainly composed of clastic particles of bauxite, high psephicity and permeability, the bauxite deposits of prove- nance are relatively far, carrying a longer time and distance sedimentary environment is the littoral-neritic sea, sed- imentary area water energy is higher and the disturbance effect is stronger, when the waters of rich aluminum hy- droxide clastic particles and gel mass around colloid aluminum hydroxide deposition, rolling, a complete oolitic bean is forming, ore structure of high textural maturity.