当斜长石双晶片十分纤细时,在旋转台上用常规的双晶法、欧拉角法等进行鉴定是比较困难的,这时必须采用其它方法。常用的方法有:垂直(010)晶带最大消光角法、垂直a轴消光角法、卡斯巴双晶及卡钠复合双晶消光角法。在工作中笔者利用诹访兼位等日本学者根据BPW数据在斜长石的消光角鉴定法研究方面取得的成果,采用了又一种确定斜长石结构状态与成分 When plagioclase bimodal is very slender, it is more difficult to identify with conventional double crystal method, Euler angle method and the like on the rotary table. In this case, other methods must be adopted. Common methods are: vertical (010) band maximum extinction angle method, the vertical a-axis extinction angle method, Caspian double crystal and sodium complex twin-crystal extinction angle method. At work, I used the results of the study by Japanese scholars such as Suwa et al. On the study of the extinction angle of plagioclase based on BPW data, and adopted another method to determine the structure and composition of plagioclase