大柴旦盐湖地表卤水底部沉积中硼酸盐的发现

Discovery of Pinnoite from the Deposit of Dachaidan Salt Lake

１９５７年中国科学院盐湖科学调查队在大柴旦盐湖地表卤水区内进行钻探。结果表明，在地表下３．６─５．１米处有一层由碳酸盐、硫酸盐、硼酸盐和淤泥形成的坚硬胶结层。该层岩芯样经系统的全化学分析、Ｘ─射线粉末衍射和结晶光学测定。确定该湖底硼酸盐是柱硼镁石（ＭｇＯ·Ｂ２Ｏ３·３Ｈ２Ｏ），这是除硼土之外，最早在该湖区发现的第一个天然硼酸盐矿物。

Early in 1957, a scientific investigation team, Chinese Academia of Sciences, came to Dachaidan town and began to investigate the salt resources of Dachaidan salt lake, from a drilling bore in the surface brine area of the lake, it was found that from 3. 6 to 5. lm under the brine floor, there was a lager precipitation with hard material which consists of carborate, sulfate, borate and clay. The results of chemical analysis and X-ray powder diffraction showed that the borate is pinnoite.