斜切[010]晶带切片上直接测定斜长石⊥[010]晶带Np′∧[010]_(max)角的新方法

• 作 者: 傅德彬
• 机 构: 吉林省地质科学研究所 长春
• 出 处: 矿物学报
• 发表日期: 1987年03期
• 关键词: 晶带 Np max 消光角 晶体侧角 钠长石 双晶面 解理面 卡斯巴双晶 函数关系

本文作者研究出来的测定Np′∧[010]_(max)的新方法,以测定斜长石斜切[010]晶带切片中钠长石面律双晶结合面(010)的倾角(θ)为手段,按a=90°-θ公式求出斜切[010]晶带切面的倾角(a)。然后,根据视消光角(φ′)和⊥(010)晶带最大消光角(φ)与a角三者间的三角函数关系求出φ角。最后,依φ角查有关图表定出斜长石成分(An％)。

A new method for the determination of Np’∧ [010] _ (max) was developed by the authors to determine the tilt angle (θ) of the albite surface (010) in the plagioclase plagioclase [010] ) As means, the tilt angle (a) of the beveled [010] crystal plane is obtained by a = 90 ° -θ formula. Then, the φ angle is obtained from the trigonometric relationship between the apparent extinction angle (φ ’) and the ⊥ (010) band maximum extinction angle (φ) and the angle a. Finally, according to the φ angle check the chart to determine the plagioclase composition (An%).