鄂尔多斯盆地陇东地区太原组铝土岩分布规律研究

Research on distribution regularity of Taiyuan formation bauxite in Longdong Area of Ordos basin

鄂尔多斯盆地陇东地区太原组铝土岩是目前勘探热点。铝土岩横向变化快、厚度薄的特点,严重制约了铝土岩的勘探进程。综合钻井、岩心观察、扫描电镜、岩石薄片、模型正演等实验方法,对太原组铝土岩分布规律进行了深入研究。结果表明:陇东太原组含铝岩系纵向上具有三段式,岩性组合主要受岩溶古地貌单元控制。铝土岩厚度随着太原组波谷振幅的增强而变大,说明铝土岩厚度与波谷振幅呈正相关性。铝土岩在岩溶高地、岩溶斜坡及岩溶洼地分别呈“鸡窝”状、带状及片状展布。

The bauxite rock of Taiyuan Formation in Longdong area of Ordos Basin is the current exploration hotspot.The characteristics of fast lateral change and thin thickness of bauxite rock seriously restrict the exploration process of bauxite rock.Comprehensive drlling,core observation,scanning electron microscopy,rock thin sections,model forward and other experimental methods,the distribution of bauxite in Taiyuan Formation was studied in depth.The results show that the aluminum-bearing rock series of Taiyuan Formation in Longdong has three sections in the longitudinal direction,and the lithology combination is mainly controlled by karst paleogeomorphology unit.The thickness of bauxite rock increases with the increase of trough amplitude of Taiyuan Formation,indicating that the thickness of bauxite rock is positively correlated with trough amplitude.In karst highlands,karst slopes and karst depressions,the bauxite rocks are distributed in the shape of'chicken nest',belt and sheet.