Study on volcanic facies of Tertiary Guantao Formation in Nanpu Sag

Above the basement of North China platform, Nanpu Sag is a dustpan-like sag developed by fault-block movement during the Mesozoic and Cenozoic. The lithology of volcanic rocks is mainly composed of basalt and tuff. Based on the division of rock flow unit and rock flow group, explosive index and thickness are adopted to divide the lithofacies. The result shows that effusive facies is the main lithofacies in the study area, and outbreak is mainly concentrated in the vicinityofthe eruption center. The distribution of volcanic rocks is studied, which provides basis for the further studyon volcanic reservoir.