判别分离结晶作用和部分熔融作用的一种新方法

A NEW METHOD OF DISCRIMINATION BETWEEN FRACTIONAL CRYSTALLIZATION AND PARTIAL MELTING

分离结晶作用和部分熔融作用， 是控制玄武岩浆化学成分变异的两种主要方式。笔者通过对比研究上述两种不同的岩浆作用过程中各种组分的变化特点。提出了一种应用皮尔斯比率图解， 判别分离结晶作用和部分熔融作用的新方法。即分离结晶成因的一套同源岩浆岩的岩石成分直线， 一般不通过坐标原点； 而部分熔融成因的一套同源岩浆岩的岩石成分直线， 必定通过坐标原点。并列举了若干实例进行讨论。该方法是以运动的观点去考察一套岩石化学分析数据，与传统的、描述性的岩石化学成分研究方法相比， 在岩石成因研究方面的确能获得更为丰富的信息。

Both fractional crystallization and partial melting are important processes that control the variation of chemical composition of basaltic magma. According to the comparison and study of the variation characteristics of each component in these different magmatic processes, we offer a new discrimination method between fractional crystallizaion and partial melting with Pearce ratio diagram in this paper. The foundation is that the composition lines of a set of cogenetic magmatic rocks formed by fractional crystallization generally don`t pass through the coordinate origin but those by partial melting certainly pass through the origin. And it is discussed with some examples. This method is characterized by studying the chemical analysis of a set of rocks with kinematic viewpoint, which can obtain more informations in petrogenesis in comparison to the traditional petrochemical study method.