The Characteristics and the Dominant Factor of Fracture Development of the Lower Silurian Longmaxi Formation Black Shale in Sangzhi

摘要

Based on the analysis of tectonic faults in Sangzhi area, black shales fracture characteristics and controlling factors of the Longmaxi formation of Lower Silurian are studied. That fracture distribution of the study area is mainly controlled by fault, where the NE-trending fault system plays the most significant role. Fracture zones are located in the anticlinal axis, as well as at the stress concentration, such as near the fault or in intersection of different fault zone. Dispersion of fracture strike and its density are controlled by the fault line, fracture develops near the fault line, which strike is mainly north-east. It contains high content of brittle mineral which becomes friable rock and has well-developed fracture.