塔里木盆地累托石的发现及其地质意义

Discovery of Rectorite and Its Geologic Significance in Tarim Basin

通过X射线衍射、扫描电镜、差热等多种手段分析,发现塔里木盆地志留系某些层段沉积砂岩中存在累托石粘土矿物,但其不是伊利石层和蒙脱石层完全按11∶规则交替排列的典型累托石,可称“似累托石”。该累托石属于沉积-成岩作用成因,是在pH值为4～5的弱酸性水介质、120℃左右或更高一些的温度条件下,由钙蒙脱石加积转化而成的钾累托石。累托石的研究成果对于地层划分与对比、储集层物性及油气藏的形成等方面的研究有重要意义。

Rectorite,a elay mineral,was diseovered in Silurian sandstone strata in Tarim basin by means of XRD,SEM,DTA,etc,Because the rectorite in not composed of 1：1 alternate arrangement of illite-montmorillonite layers,it eould be named “pararectorite”,The study indieates that the pararetorite belongs to K-rectorite transformed by Ca-rectorite,and sedimentation-diagenesis origin in weak acidie aqueous media with pHvalue raging from 4 to 5 and under 120℃or more,The results from the pararectorite research will be of great significance to te stratigraphic classification or comparison,the reservoir rock feature and the formation of the hydroearbon reservoirs in Tarim basin.