Abstract:Based on the geological survey, through drilling, fault gas radon detection, shallow seismic detection and intelligent micro-motion detection, we reveal the geometric characteristics of buried faults F1 and F2 in the Houhai reclamation area of Shenzhen, and analyze the weathering genesis of the NW trending faults. The results show that: 1) The buried faults F1 and F2 are developed in Yanshanian granite, and the occurrences are N38°-40°W, NE, 59°-63° and N50°W, NW, 70°, respectively. The width of the faults are 30-35 m and 40 m, respectively. Cataclasite rocks can be widely found around the faults and the chlorite phenomenon is obvious as well. A thin layer of powdery rock is developed in the fault surface zone, but the overlying Quaternary strata is not disturbed. The faults belong to brittle fracture system and present both tensile and reverse torsional features. 2) The relative activity of the buried faults are measured by fault gas Rn concentration intensity, which shows that the relative activity of F1 buried fault is strong. 3) F1 and F2 faults control the southwest and northeast boundaries of the weathered trough respectively. The main causes of the weathered trough are that the hanging wall of the extensional fault is more cataclastic compared to the lower wall, the cracks, pores and secondary faults are denser, and the rapid weathering of feldspar in broken granite under the action of water and temperature.
WANG Xianneng,WANG Yunsheng,LI Zhibo et al. Comprehensive Exploration of the Northwest Buried Faults in the Houhai Reclamation Area, Shenzhen[J]. jgg, 2022, 42(6): 577-583.