Tectonic evolution of the Huangling uplift and its control effect on shale gas preservation in South China

Significant breakthrough of shale gas exploration has been made in Lower Cambrian and Sinian shale on the north margin of the Yangtze block, South China. In this paper, the authors focused on the preservation condition of shale gas, with the purpose of investigating the tectonic evolution history of the Huangling uplift by means of geological survey and 2D seismic, geochronological and drilling data. The results are as follows:at~800Ma, granite intrusion took place in the Huangling dome basement, primarily shown by granites replacing metamorphism rocks; during 800~200Ma, no significant tectonic movement occurred, with no geochorologic data; the Sinian shale was buried at the depth of about 8km during Middle Jurassic. This study indicates that the rigid basement of the Huangling uplift was mainly composed of homogeneous granite, without intensive deformation. As the main challenges of the widely distributed Lower Cambrians and Sinian shale are high-maturity and intensive deformation, a geological unit with a dome probably is a favorable zone for the old age shale gas. Therefore, it is shown that the adjacent zones of the the Xuefengshan, Shennongjia and Hannan are geological units with a dome and probably have potentials for the exploration of shale in the Lower Cambrian strata.