摘要
西宁盆地含坡缕石粘土赋存于第三系中,它由粘土矿物(伊利石、坡缕石、绿泥石等)、碳酸盐矿物(白云石、方解石)和陆源碎屑矿物(石英、长石、云母)组成。通过岩石化学统计相关系数和二次平差曲线对变化指数、相依系数、均方差研究,总结了坡缕石含量从东到西、从南到北增高的变化规律;碳氧同位素组成显示了湖相沉积特点,微量元素含量偏高,pH值8.75—9.23,反映了坡缕石形成环境为富镁弱碱—碱性的淡—咸水湖。研究了坡缕石的成矿地球化学作用,指出了寻找坡缕石的方向。
The palygorskite-bearing clays of the Xining basin occured in Tertiary systemand consist of clay minerals (illite, palygorskite,chlorite,etc.), carbonate minerals (dolomite, cal-cite)and terrestrial clastic minerals (quartz, feldspar, mica). Based on the study of petrochemistryand statistics the authors have summarized up the variation regularity of palygorskit content in-creasing from east to west and from south to north. The isotbpe composition of carbon-oxygen,high content trace elements and pH value 8.75-9.23 all reflected that the palygorskites wereformed in an environment of fresh to brackish lake,characterized by rich magnesium and pooralkaline. At last the authors described the minerogenic geochemical process and pointed out thedirection to prospect palygorskite deposits.
