GRAVITY AND MAGNETIC EVIDENCES FOR THE SUTURE ZONE BETWEEN NORTH CHINA PLATE AND SIBERIAN PLATE

By reprocessing the gravity and magnetic data in Northeast China, the paper discusses the location of suture zone between North China Plate and Siberia Plate, which has been controversial for long, and gains a new understanding. It is considered that, in Northeast China, the suture is with an approximately equal width about 240 km, starting from north Chaoyang-south Tongliao in the west with NEE trend, turning SEE through north Shenyang-north Changchun, to north Tonghua-south Hunchun. Such understanding mainly comes from the comprehensive analysis of regional gravity and magnetic data, including the primary data, vertical and horizontal derivatives, horizontal gradient mode, different upper continuation heights, several filtering such as wavelet, small subdomain and interpolation, and anomaly characteristics reflected by various processing like signal extraction and enhancement. There are obvious differences in gravity and magnetic anomaly between the south and north, inside and outside of the zone, commonly showing anomaly dislocation, curve distortion, trend change, scale difference and feature interaction between inside and outside. For example, the Songliao Basin has undergone significant changes in the north-south width, and even the terrains and mountains are differentiated due to the existence of the suture zone.