Research On The Early Cretaceous Tectonic Uplift History Of The North Dabie Belt

This study tests C-axis fabric patterns of the plutons and gneiss quartz in the NorthDabie belt (NDB), much of the patterns contain non-coaxial deformation characteristics andrecord direction of motion of top-to-NW. Therefore, quartz C-axis patterns indicate thedeformed plutons and gneiss in the NDB had similar direction of motion. Because they hadsimilar deformation time, the deformation of these plutons occurred in migmatizationprocess. This work supports the lower crust flow occurred in the migmatization process.This work takes electron probe test on the early Cretaceous deformed plutons in theNDB. Using the amphibole Al (aluminum) pressure gauge to calculate rock emplacementpressure and convert the emplacement depth. Using the previous dating results of theseplutons, this work analysize the uplift history of the NDB. Based on these works, we getsome new knowledges of the Dabie orogenic belt: Early Cretaceous uplift activities can bedecomposed into homogeneous and inhomogeneous uplift. Homogeneous uplift wasproduced by detachment shear zone and a series of brittle fault; inhomogeneous upliftrelated to granite emplacement process. The early Cretaceous extensional activities haveled to a uniform uplift of at least10km. The deepest exposure occurred north Luotian area,the total uplift is about22km, which contains inhomogeneous uplift at least5km. There aredifferent uplifts in the western and eastern part in the NDB, supporting two secondarydomes in the Dabie orogenic belt.