THE CHARACTERISTICS OF SUBPLATE DIVISION OF CRUST AND UPPER MANTLE IN THE CONTINENT OF CHINA
Based on the deep seismie sounding and other geophysical data, thecontinent of China can be divided into five subplates and further dividedin to 25 microplates. The South China plate has an average crustal thickness of 32--45km,with a high P--wave velocity and clear layered structure.The depth ofasthenosphere changes from 80 km in southeastern margin to 200 km inwestern margin.North China plate has average crustal thickness of 35--45km,P--wave velocity is lower and a low velocity zone is clearly obsenved.Depth of asthenosphere in that area is 60--100km. The Qinghai--Tibet Plateconsists of several microplates split from the Gondwanaland and Eurasia.Crust of this area has thickness of 60--76km,depth of asthenosphere is 120--140km, Mean P--wave velocity is the lowest. Comparing the results of body wave, we found that the velocity in uppermantle at 100--300km depth is 8.3--8.4km/s in Qinghai--Tibet and inNorth China Plates, while it is only 8.1--8.2km/s in South China Plate. The density contrasts of crust and upper mantle are estimated for eachplate.Map of crustal thickness in the continent of China is obtained.Therelationships between subplate division and present tectonic activity in thecontinent of China are discussed in detail. A possible reconstruction of theof the continent of Chins is illustrated.