Depositional system of lower Nantun Formation in South Tamuchage-South Beier Sag

Based on the data of core,well drilling,seismic and laboratory chemical analyses,the depositional system of the lower Nantun Formation in the South Tamuchage-South Beier Sag is discussed.Fan-delta,near-shore subwater fan,lake floor fan and lacustrine depositional system characterized by steep slope,near source and multi source account for large scales in the study region.Fan-delta,near-shore subwater fan and deep-lake mud deposits are the most developed sedimentary systems.According to the analyses of seismic facies,seismic features,sandstone contents and heavy minerals,it is discussed in this paper the depositional distribution characteristics of the lower Nantun Formation in the South Tamuchage-South Beier Sag.