| 略论我国前寒武纪变质作用和地壳演化的某些特征 |
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| SOME CHARACTERISTICS OF THE PRECAMBRIAN METAMORPHISM AND CRUSTAL EVOLUTION OF CHINA |
| The Precambrian crust of China mainly consists of four metamorphic domains, namely, North China, South China, Northwest China and Southwest China metamorphic domains.High temperature metamorphism (granulite facies) prevailed in the northern of North China domain in the Early and Middle Archean (about 2800-3000Ma and earlier), and the metamorphism which mainly represents medium temperature (ampbibolite facies) metamorphism widely occurred in whole North China in Late Archean (about 2500Ma), resulting in the first cratonization of this region. In Early Proterozic, continent crust grew up along the craton margin, which was characterized by regional dynamothermal metamorphism, and aulacogens were formed in some weaker belts inside the solidified craton, which was characterized by regional low temperature dynamic metamorphism (greenschist facies).In Northwest China, regional dynamothermal metamorphism widely occur- red during Early Proterozoic. This was followed by cratonization of Northwest China together with North China and the western part of South China around 1800-1900Ma, thus constituting the initial continent craton of China. Regional low temperature dynamic metamorphism (greenschist facies) took place along some aulacogens in Middle-Late Proterozoic.The western part of South China domain was subjected to regional dynamothermal rnetamorphism in Early Proterozoic. This was succeed during Middle-Late Proterozoic by the extensive development of regional low temperature dynamic rnetamorphism (greenschist facies) in South China, the major part of which was then cratonized and combined with North China craton and Northwest China craton to form a single major tectonic domain, the craton of China in Late Proterozoic (about 800Ma).The Southwest China metamorphic domain (including Tibet and a part of West Yunnan as well as the southern part of Qinghai), which probaly underwent extensive, regional dynamothermal metamorphism in Late Proterozoic, formed a part of the basenent of the northern margin of the Gondwana craton.Taking the Precambrean basement of China as a whole, the Archean terrains of China are marked by the wide distribution of medium temperature amphibolite facies and by the rather peristent occurrence of high temperature gianulite facies along the northern border of the North China domain and a few other regions. Regional dynamothermal metamorphism, which varied from greenschist to amphibolite facies (later is dominant), was the result of metamorphism chiefly in the Early Proterozoic epoch. Regional low temperature dynamic metamorphism (greenschist facies) was mostly limited in the aulaco-gens after the continental cratonization. It seems that the aulacogens might have formed in a transitional stage to further consolidation of the continental craton or served as the predecessors to further disintegration of the continental craton. |
| ZHANG Shou-guang.1987.SOME CHARACTERISTICS OF THE PRECAMBRIAN METAMORPHISM AND CRUSTAL EVOLUTION OF CHINA[J].Acta Geoscientica Sinica,9(2):27-39. |
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