角闪石成因矿物族及其应用

GENETIC CLASSIFICATION OF HORNBLENDES AND ITS APPLICATION

作者选用成因、产状清楚的581个角闪石化学分析资料,在详细研究不同成因属的晶体化学一成因特征后,选择能反映成因特点的端元作晶体化学一成因图解,圈定九个角闪石成因区,并说明了它的实际应用。

This article introduced the idea of Genetic Mineral Groups and using hornblendes as an example illustrated how the genetic classification was made on the base of rystallochemistry of this group of minerals.The author has reviewed 624 reports on chemical analysis of amphiboles and after choosing and checking 589 of them with their occurrences, renamed them with the IMA nomenclature(1978). Plots are drawn according to the values of Si-Mg-AlVI-AlIV-Fe3+-Fe2+-Ca-Na-K in different rent crystal sites. Genetic varieties and subvarieties are distinguished by these characteristic values,, This implies that the values are related to factors such as host rock, temperature, pressure and thermal fluids appearing at later stage and are reflected in different isomorphisms at different cryst-allographicsites which results in the change of crystal system, space group and mineral species. In more complicated structural types this means a polygene history of the mineral.This article has provided with crystallochemistry-genesis diagrams for subclasses of Mg-Fe-Ca-amphibole, Ca- amphibole, Na-Ca-amphibole, and alkaline amphibole. So it is possible for any kinds of amphibole to find its position in the rhombic picture plotted with different genesis regions(or subregions). At last, the usage and the reliability of the picture are exemplified.