CHARACTERISTICS OF PLATE TECTONICS AND DIVISION OF GEOTECTONIC UNITS IN LIAONING REGION

Based on the theory of plate tectonics and the results of the 1:50000 regional geological survey in recent years and related achievements, the crustal evolution and development of Liaoning region are analyzed. It is suggested that the crustal development in the region should be divided into Early Precambrian continental accretion tectonic system and Mesoproterozoic plate tectonic system. Because of the discovery of the Mesoarchean-Paleoproterozoic greenstone terrane and Paleoproterozoic rift, the Early Precambrian era can be regarded as primitive plate period; while the Mesoproterozoic to Paleozoic as ancient plate period; and since Mesozoic, modern plate. On this basis, the tectonic units of Liaoning region are divided. The Grade Ⅰ unit is Tarim-North China plate. Grade Ⅱ involves Tianshan-Chifeng continental margin active belt and North China landmass. The Grade Ⅲ units include Jianping-Xifeng Variscan continental margin orogeny, HebeiLiaoning massif, Tieling-Qingyuan micro-massif, Liaoning-Jilin massif and Lower Liaohe-Liaodong Bay Cenozoic rift. There are 16 tectonic units of Grade IV. The characteristics of the 5 units of Grade Ⅲ are described in this paper to clarify the crustal evolution in the region.