Abstract:

Heilongjiang plate, located in the northeast Asia, consists of Erguna-Hingan, Songnen-Zhangguangcai Ridge, Jiamusi, Xingkai microplates and Wandashan terrane. Since the comprehensive geophysical works on the Manzhouli-Suifenhe geoscience transect (GGT), magnetotellurics (MT), gravity, magnetic, and seismic probing have been conducted in the Northeast China. The obtained results play a basic role in the geodynamical research and mineral exploration in East Asia. The achievements from these works include: 1)Indicated by the seismic wave velocity, formations of Carboniferous-Permian period (C-P) basement exist at least in the north and the south of the Songliao basin, where should be the future regions for oil and gas exploration；there is a great oil-gas potential in the Binbei district of the Songliao basin with the area of 70 thousands km2. 2)The interpretation of MT data show the subduction of intercontinental sea between the microplates in the Heilongjiang plate with the remnants of oceanic crust; the image can be observed that the ancient Asian Ocean subducted to Heilongjiang plate between the Heilongjiang plate and the south of North China plate. 3)The origin of the gravitational gradient zone along Daxinganling Mountains-Taihang Mountains-Wuling Mountains is presented by the “triple-junction model”. The nearvertical seismic reflection profiles show a “break zone” of Moho interface along nearly northsouth direction in Songliao basin. 4)A 3D migration theory with finite aperture is established in seismic imaging for oil and gas exploration. Based on a 1D time-variant median filtering technique to decrease seismic random noises, 2D median filtering technique is developed. Then the time-frequency peak filtering denoise technique is introduced into seismic exploration; the least square support vector regression filter based on Ricker wavelet kernel is established; a reconstruction technique of Seislet transform to seismic data and an extended higher-order Seislet transform are presented; based on the Trace transform, a Co-Core Trace transform is built up to eliminate seismic surface wave. The pseudo-spectral method is used to simulate the wave propagation which shows the attenuation of qS wave is lager than that of qP wave in the viscoelastic anisotropic media; the seismic events are detected in the background with strong noise by the chaotic oscillator system, and the hyperbolic time-distance relation filter is set up. A migration imaging system for ground penetrating radar (GPR) is used for landmine imaging successfully.

Key words: Heilongjiang plate, Chinese Manzhouli-Suifenhe geoscience transect (GGT), formations of Carboniferous-Permian period (C-P) basement in Songliao basin, subduction of intercontinental sea, Moho interface, 3D migration theory with finite aperture, 2D median filtering, chaotic oscillator system, ground penetrating radar (GPR)