北京密云太古宙片麻岩研究

A Study of the Archeozoic Gneiss in Miyun,Beijing

本文研究了北京地区密云幅、墙子路幅、高岭幅范围内的太古宙片麻岩，英云闪长岩—花岗闪长岩—奥长花岗岩系列，辉长岩—石英闪长岩系列，晚期片麻岩脉群和小侵入体。研究后认为：①各片麻岩系均为变质侵入岩；②英云闪长岩—花岗闪长岩—奥长花岗岩系（ＴＴＧ）的岩浆来源于深部基性岩的部分熔融；③辉长岩—石英闪长岩系列（ｇｄ－ｑｄ）岩浆来源于上地幔岩石部分熔融；④构造运动引起的矿物晶格变形和摩擦可转换为变质作用的重要热源；⑤晚期酸性片麻岩脉体的岩浆形成于早期ＴＴＧ岩系和ｇａ－ｑｄ岩系在变质过程中的部分熔融。密云地区的太古宙片麻岩可能在２９００Ｍａ以前基本结束麻粒岩相变质阶段，在早元古代时期结束角闪岩相变质阶段。

his paper studies the archeozoic gneisses of which the primacy ricks includ tonalitegranodiortetrondhjemite series,gabbroquartz diorite series,later gneiss vein system and minor intrusions in the sheets of Miyun,Qiang Zhilu,and Gaolin of Beijing areaAfter studying the writer thinks:1,the gneiss series are all metamorphosed intrusive rocks;2,the magma of tonelitegranodioritetrondhjemite series (TTG) is originated from the partial fusion of the basic rocks in the depth;3,the magma of gabbroquartz diorite series (gaqd) is derived from the partial fusion of the upper mantle rocks;4,the heat source of the metemorphism comes from the transformation of the tectonic deformation and friction of mineral crystal lattice;5,the magma of the later acid gneiss vein body forms from the partial fusion during the metamorphic process of the earlier TTG rock series and gaqd rock seriesThe archeozoic gneiss in Miyun area might probably conclude the granulite facies before 2900 Maand the amphibolite facies might conclude in the earlier proterozoic era