The drilling of Lower Cambrian shale gas in the northern margin of Mount Daba shows good prospect. A set of dark shale strata are generally developed in the lower Cambrian in this area

but the stratigraphic heterogeneity is strong

and the sedimentary facies change obviously in the region. It is helpful for the further exploration and development to the study shale sedimentary characteristics of the Lower Cambrian in this area and analyze its influence on the differential enrichment of organic matter. On the basis of outcrop section in Maoba of Ziyang and experimental data

the researches are carried out from three aspects: the division and correlation of sedimentary facies

the analysis of sedimentary mode and the analysis of favorable sedimentary facies zones. The Lower Cambrian in the study area can be divided into four sedimentary subfacies: sub abyssal rifting trough basin facies

deep water shelf facies

shallow water shelf facies

and platform edge slope facies. Longitudinally

the water body changes from deep to shallow

and the contents of carbonaceous and siliceous gradually decrease

while the contents of clayey and carbonate gradually increase. The dark mud shale developed in the lower Cambrian Lujiaping Formation deep water shelf facies in Langao-Zhenping stratigraphic district has the larger thickness and higher content of total organic carbon and brittle minerals

which is a favorable sedimentary facies belt for the development of high-quality shale.