ORIGIN OF PSEUDOTACHYLITES FROM THE EASTERN DABIESHAN OROGENIC BELT

Recent field survey in the eastern Dabieshan has revealed extensive occurrences of pseudotachylite. The pseudotachylite tends to occur in the NE-SW trending fracture zones or shear zones which parallel the Tan-Lu fault zone and cut all the pre-Cretaceous geological bodies. Mylonitic bands are developed in some pseudotachylites. This paper mainly discusses the origin of the pseudotachylites according to the geochemistry between the pseudotachylites and their host rocks, as well as the characteristics of the microstructures gained by optical microscope and SEM imaging.