如何正确使用玄武岩判别图

为了正确使用玄武岩判别图,在投图之前要对样品加以筛选并对数据作出估计。还要将样品适当分组,投图时应遵循一定的程序。文中讨论了可能出现的几种判别结果及可能的解释方案,指出了判别图的局限性,认为玄武岩判别图所标定的各种构造环境的分区,实际上代表的是各种不同的岩浆类型。作者认为,投在洋中脊玄武岩区域的玄武岩绝大多数并非来自大洋中脊环境。

THE CORRECT USE OF THE BASALT DISCRIMINATION DIAGRAM

To use the basalt discrimination diagram correctly it is necessary to sort the specimens carefully, to make an order of magnitude estimate and to group the samples properly before plotting starts, Some procedures should be followed during plotting. The paper deels with the interpretation of the resulting plots, likely causes of ambiguous resualts and limitation of basalt discrimination diagram. The author indicates that all areas of the tectonic setting determined by basalt discrimination diagram, in practice, show distinctive magma types, It is quite possible that most of basalts plotted into MORB area are not from mid ocean ridge setting.