West Qinling - Songpan Tectonic Node 3d Lithospheric Structure,

The western Qinling - Songpan tectonic node is an enormous structure, which was formed through various conjunction and transformation of different orogens and massifs that constitute the China continent during the completion of main amalgamation of China continent under the coactions of the Alps - Himalayas, the Pacific ocean and the circum Siberia tectonic dynamic systems. With the complex structures and constituents , the tectonic node provides an excellent site for study of China continental geology and continental dynamics.Today's 3-dimension lithospheric structure of the tectonic node is the basis of doing research for tectonic evolution and answering relevant continental dynamic questions. The 3-dimension lithospheric structure is described by common processing and wavelet analysis of Bouguer anomaly, geoid anomaly computation and digital elevation model(DEM) analysis, in combination with deep seismic sounding (DSS) ,magnetotelluric(MT), seismic tomographic(ST) and geological data.The faults are compartmentalized into different categories and the planar combinatorial charateristics of the faults is analysed. It is considered by the author that the formation of the NW-trending and NE-trending conjungate shear faults and NS structures is resulted from the interaction of the three tectonic dynamic systems. Structures in different trending direction and different depth and their relationship are interpreted and deduced. There is uncoupling beteewn the relatively shallow structures and deep structures in Songpan-Ganzi, where the existence of the weak layers with lower density (lower velocity, lower electrical resistivity) is an important condition of the uncoupling. Several important faults are interpreted and personal opinions about the westward extending of Mianlue and Shangdan sutures are given. Finally exploratory research of dynamic mechanism is done.