The Early Precambrian Collisional Orogenic Process and Plate Tectonics: Chance and Challenge of Precambrian Geology

One of the important issues for the current geological research focuses on when the plate tectonic process began.It is generally believed that modified plate tectonic model can be used to Neoarchean geological time. However,there is significant difference between the early Precambrian and modern plate tectonics,such as size of continental block,type of orogen and collisional orogenic process,etc.The initial occurrence of classical collisional orogenic belts in the history of the earth has important implication for tectonic evolution,which involved the onset of plate tectonics,the occurrence of the first supercontinent,Wilson cycle and collisional orogeny.The study of early collisional orogenic belts will provide a relatively comprehensive understanding of Archean plate tectonics.In the central part of North China craton(NCC) basement,a north-to-south trending collisional orogenic belt(2600~2500 Ma) has been identified,which preserved distinct composite fold of supracrustal sequences,thrust-fold structures of different crustal levels,ophiolitic melanges.It is suggested here the 2.50 Ga tectonothermal episodes associated with the Orogenic Belt provide an important constraint for the early Precambrian tectonic evolution of North China.Its correlation with other orogenic belts of the world has important implication for the reconstruction of the NCC within the early supercontinents or supercraton.So,the study of collisonal orogenic belt is one of the most important target topics for early Precambrian plate tectonics.The investigation on the vertical variation of structural patterns with foreland fold-thrust belt and foreland basins will provide insight to understanding of early plate tectonic boundary-related orogenic process.