旋转台五轴法对Nm近于水平和垂直的单斜辉石、单斜角闪石C∧Ng的测定方法

The Method of Five-Axis Universal Stage in Determination of C∧Ng of Monocline Pyroxenes and Amphiboles

前人用旋转台对单斜辉石,单斜角闪石的C∧Ng测定方法主要分两大类,一类是解理法,另一类是双晶法。解理法又分一组解理和两组解理四轴投影法及两组解理五轴法。在双晶法中分C·柯尔仁斯基直接求C∧Ng法和间接(投影)求C∧Ng法(T·Nemoto1938年和F·J·特涅尔1942年提出)。前人识为双晶直接测定法中,当Nm近于垂直于薄片平面时,不能按正常方法进行测定,C·柯尔仁斯基提出了用统计方法求出C∧Ng。但这种统计法总是存在不同程度的误差。当Nm近于平行薄片平面时(<20°)这种颗粒用柯尔仁斯基方法即不能.

The four-axis cleavage method and twin method are used now as main means in determining CANg of monoclinic pyroxenes and amphiboles.However,these methods can not determined satisfactorily in case mineral’s Nm is nearly parallel or method in determination of CANg of these minerals with five-axis universal stage,which not only counteract the weakness of the former method,but also make the determination of the monoclinic pyroxene and am-phibole species more rapid and accurate.