华北地台某些地区变质岩中的钙质角闪石

本文研究了华北地台某些地区变质岩中的130个钙质角闪石的化学成分、多色性等特征及其控制因素,认为角闪石的含铁度主要决定于寄主岩石的〈FeO〉/MgO比值,而Ti、Al~(IV)、(Na+K)含量主要决定于变质条件,Ng方向多色性主要与Ti的含量有关。

CALC-AMPHIBOLES OF METAMORPHIC ROCKS FROM DIFFERENT PARTS OF THE NORTH CHINA PLATFORM

130 samples of calc-amphibole from Precambrian metamorphic terrains in Shanxi, Hebei, Liaoning, Jinlin and shandong Provinces of the north part of North China Platform were studied in respect of their chemical composition and pleo-ghrpic property. It is recognized that the (Fe2++Fe8+)/(Fe2+ + Fe3+ +Mg) of the amphiboles was mainly related to the FeO/MgO ratio of the host rock, the Ti, AlTV, and (Na+K) contents are mainly to the metamorphic condition,and the pleochroism in Ng direction to Ti content of the mineral.Calc-amphiboles of different generations were frequently met in metamorphic rocks in these districts.Hence,they may be used as an important criteron to trace the metamorphic evolution.