Ductile shear zone of changed shear sense: EBSD characteristics and kinematics of ductile shear zone from 2010 to 2145m of the main borehole in Chinese Continental Scientific Drilling (CCSD)

作者：Tang ZheMin^*; Chen FangYuan

来源：Acta Petrologica Sinica, 2007, 23(12): 3309-3316.

• main borehole of CCSD
• ductile shear zone
• shear sense

There is a ductile shear zone (2010 similar to 2145m) between eclogite unit (depth 1596 similar to 2038m) and gneiss unit(depth 2038 similar to 2500m) in main borehole of Chinese Continental Scientific Drilling(CCSD) located in southern part of SuLu ultra-highpressure metamorphic terrane. Ductile shear zone is composed of strong deformational rocks of mylonitic retrograde metamorphic eclogite, granitic mylonite et al., foliation of ductile shear zone dip to SEE, dip angle changes from average 52 degrees in upper part to 32 degrees in middle and lower part. Attitude of stretching lineation is basic identical with dip of foliation, ductile shear zone resulted from exhumed deformations in 220 similar to 200Ma. Microstructure and lattice-preferred orientations of quartzs from mylonitic retrograde metamorphic eclogite and granitic mylonite indicate that exhumed early stage have a SEE-NWW thrust shear sense and exhumed later stage have a NWW-SEE normal-slip shear sense. Forming of ductile shear zone(2010 similar to 2145m) in main borehole from CCSD is related with site of ductile shear zone(2010 similar to 2145m) which locate in boundary between eclogite unit and gneiss unit. Attitude of foliation, stretching lineation of the first stage N-S direction ductile shear deformation in ultra-highpressure stage is different from the second, the third stage SEE-NWW direction exhumed deformation.

• 出版日期2007-12
• 单位中国地质科学院