Abstract: The orthopyroxenes of granulite facies in Miyun region,Beijing,are hypersthenes,the end members of which are Wo 4% En 52—59%,Fs 37—44%,and ferrous index 38.8—45.5%; while the clinopyroxenes in pyroxene granulite and hornblende granulit ubfacies are augites with end members of Wo 41—43%,En 39—43%,Fs 14—20%,and ferrous index 30.8—34.4%.According to Saxana's two pyroxenes geothermometer method,it has been calculated that metamorphism temperature in this region is 702—887℃,while the pressure 9—10Kb.

摘要： 北京密云麻粒岩相中的斜方辉石为紫苏辉石,斜方辉石的端员成分Wo4%,En52—59%,Fs37—42%,含铁度f_opx39—46,化学成分特征是富Mg、Ca、Al贫Fe²⁺、Mn。角闪麻粒岩亚相和辉石麻粒岩亚相中的单斜辉石为普通辉石,端员成分Wo41—43%,En39—43%,Fs14—20%,含铁度f_opx31—35,化学成分特征是富Mg、Al、Na贫Fe²⁺、Ca。通过Saxana二辉石地质温度计的计算表明,本区麻粒岩相变质作用的温度为702℃—887℃,压力为9—10Kb。并用Mereier单个辉石地质温度计进行了验算,结果是吻合的。