TECTONICS AND STRUCTURE OF QINLING OROGENIC BELT

The Qinling orogen has 2 kinds of orogenic basements. The main orogeni c phase was characterized by the oblique subduction and collision of 3 plates at 2 suture zones. There are a number of vertical accretionary structures under the control of deep-seated thermo-tectonic processes . The present 3-D model of the Qinling is a ''flyover-like'' framework . Deep geophysical field is featured by nearly South north-trending an omalies, while the upper crust is dominated by east-west-trending stru ctures. Between them are the middle and lower crusts which are in a th eological state of the horizontally flattening. Fundamental structures of the upper crust was built during the main orogenic phase, which co ntains residual structures and is intensively superposed by the late i ntracontinental tectonism. This tectonic model for the Qinling orogen is distinct from the existing ones in that it represents a complicated development of diverse tectonic regimes. This model cannot be either interpreted by an individual existing model.