The Tectonic Deformation About The South Edge Of Dabie Orogenic Belt

This paper studied the regions in the southern edge of the Dabie orogenic belt Xishui– Malong area. The rocks exposed in this region can be divided into Tie Ye group, Ma Qiao group and Feihu Shan group. The observations of rock micro-structure, finite strain and temperature and pressure analysis are carried out on these three groups. This paper get the region's tectonic geometry model tube. Tie Ye group in the center of tubular model, capable of strong; Ma Qiao group and Fei Hushan group are model composed of tubular outer wall. There are rock felsic veins filling. The experiment of rock finite strain has made on the Ma Qiao region, the shouthern edge of Dabie orogenic belt, measured the strain ellipse axial rate Rs=1.5-2.0, this result also indicates that the tectonic belt rocks plastic deformation occurs. Southwestern edge of the study area developed fault yindian - Ma Long fault is strike-slip fault. The analysis of the geology of the area deformation of the North West - South East, the impact of the tensile stress, the stress of the direction of the Yangtze plate to the North China plate oblique compression plate arising from the weight and superimposed the Pacific Plate to the East Asia plate collision in the North West - South East to the horizontal component of force generated. Zircon U-Pb dating used for gneiss of Tectonic belt in the southern edge of the Dabie Mountains. The southern edge of the Dabie Mountains belt Malong granitic gneiss area of the original rock age of 837±22Ma, MSWD = 3.0, with the former southern edge of the belt in the Dabie Mountains of age obtained is consistent for the multi-phase tectonic activity remaining after the Proterozoic period Yangtze craton of the original rock. The distribution of proceeds under the age spots near the intersection of the inconsistencies in line, derived from belonging to the Triassic age, Indo-China period, the weighted average of its 207Pb/206Pb age were 222±31Ma, MSWD = 81, the age of the Yangtze plate relative to the Qinling - Dabie orogenic belt intracontinental subduction of time. The age of Fei Hushan group harmonic line below the line under the intersection with the concordia age of 151±79Ma, record Yanshan period tectonic activity in the area, is the era of returned ultra-high pressure metamorphic rocks.