LITHOSPHERIC ELECTRICAL STRUCTURE OF THE QINLING OROGEN AND ITS GEODYNAMIC IMPLICATION
CHENG SHUNYOU1\ ZHANG GUOWEI1\ LI LI2 1 The Key Laboratory of Continental Dynamics, Ministry of Education;Department of Geology,Northwest University,Xi'an 710069, China 2 Institute of Geophysical and chemical exploration, Ministry of National land and resources, Langfang 065000, China
Studying in detail three-dimensional lithospheric electrical structure features in the Qinling orogenic belt, and combining with other geophysical and geological data analysis, we find that since Mesozoic-Cenozic eras, particularly late-geological time, as a result of continuous intracontinental subduction beneath the Qinling orogen by the North China block (NCB) southward and the Yangtze block (YZB) northward, present Hinterland fault-bounded fold zone (HLZ) and North Qinling thick-skinned imbricated thrust zone (NQZ) has a superimposed and thickened lithosphere and is in initial delamination period owing to the lithosphere of the South Qinling zone (SQZ) wedging into within that of the NQZ. In contrast, the SQZ is undergoing delamination and underplating to cause mass-energy recycling between crust and mantle, and around the Foping region a new plume is probably developing. In addition, the lithospheres within the Qinling orogen and its southern and northern boundaries also accompany different properties of intensive lithospheric strike-slip faulting to result in mass lateral transfer. Finally, we discuss geodynamic implication of the coexistence of the thickened lithosphere and a large-scale tectonic delamination as well as strike slipping.