Mirror-image thrusting in the South China Orogenic Belt: tectonic evidence from western Fujian, southeastern China

The Mesozoic orogenic belt in south China is readily divided into two fold and thrust belts and a central multiply-deformed zone of ductile deformation dominated by folds with steeply dipping axial planes. Southeast-directed thrusting in the eastern belt and northwest-directed thrusting in the western belt resulted in a mirror image of one another during the Mesozoic. The eastern fold and thrust belt can be further divided into three domains that overlap one another and exhibit a southeast-verging wedge-like geometry and kinematics. Deviatoric stress has been calculated from quartz dislocation density at 91.5 MPa, 74.5 MPa and 73.8 MPa, decreasing toward the southeast. Upper Devonian and Lower Carboniferous sandstones have been used to constrain bed length for cross-section balancing to estimate crustal shortening from three typical areas. These indicate 45%, 41.6% and 37.3% shortening and suggest that 110 km of contraction has been achieved as a result of thrusting. This orogen con-elates with the Ogcheon Belt in South Korea to the northeast. To the southwest it appears to correlate with a thrust belt in western Guangdong. This southeast-verging thrusting may be at least partially controlled by Cathaysia to the east. (C) 1999 Elsevier Science B.V. All rights reserved.