Abstract: In the area from Beijing to Chengde the extensive occurrences of the Archaean-Proterozoic crystalline rocks are composed mainly of two suits of metamorphic rock series; the Miyun Group in the lower member dominated by hypersthene-granulite and hornblende-granulite, being the type of orthogneisses and named "gneiss series" in the past: the Zhangjiafeng Group (or Huairou Group) in the upper member in predominance of crystalline schist, belonging to the paragneisses, and which used to be referred to as "crystalline schist series".In this paper the earth’s origin was presumed by virtue of the above-mentioned metamorphic rocks. It is assumed that the original earth may stem from the nebula. Originally the earth would have a layer of " a basic "scoria shell" after it had formed. And this may be the initial embryonic crust of igneous rocks. Because of its outer crust the transmission of heat was difficult, and then the rock differentiation of the inner crust took place, leading to the generation of the magmatic source in the upper crust.Geothermal and magmatic sources having an effect on the scoria shell would cause metamorphisms and then form the crust of basic orthogneiss, the lower crystallized crust.At that time the wavelike folding deformation due to the contraction happened over the crust. However, the deep-seated faults would never occur within the crust. Consequently, a large scale of intrusion and eruption of the magma was of little possibility and only the dissemination and injection of the magma appeared in dispersion form, leading to a general migmatization. The temperature of the ground surface had since decreased rapidly and the solid crust was under the action of the internal and external stresses deformed and fractured to cause uplifts and depressions, and followed by the erosion and sedimentation. The consolidated sedimentary rocks were accompanied by the magmatic activity and the metamorphism to form the paragneisses. i. e. the upper crystalized crust.On the basis of the composition and occurrences of the ancient rocks together with the characteristics of metamorphism, magmatism and tectonic movements, the earth’s origin discussed in this paper may be assumed to be a general rule for the accretion and evolution of the earth.

摘要： 古老变质岩系主要由前人称为“片麻岩系”和“结晶片岩系”两大套岩系组成。当地球成球之后,表面首先形成一层“基性焦壳”,在热封闭条件下,壳内产生花岗岩岩浆源,注入此原始地壳,并引起变质作用,形成基性正片麻岩地壳——第一层结晶地壳。然后,固体地壳发生形变和破裂,产生侵蚀、沉积,并伴随着岩浆活动、变质作用形成副片麻岩类——第二层结晶地壳。由此,本文以北京及其外围地区的古老变质岩系为依据,阐述了地球的形成和演化规律。