BRAIDED RIVER DELTA SEDIMENTARY FACIES OF LOWER GUANTAO FORMATION OF THE NEOGENE IN EASTEN JIYANG DEPRESSION

Some facies marks of submerged sedimentary (such as shale color and palaeobiological fossil) and reworking marks of lake current (such as lithology and texture, sedimentary structure, grain size analysis, litholic composition and its maturity, facies sequence in the cores, plane pattern of sand body) have been found in the lower Guantao Formation of the Neogene in the eastern Jiyang Depression. It is proved that Guantao Formation of the Neogene in Jiyang Depression is a braided river delta sedimentation rather than fluvial facies. The braided river delta has developed submerged braided river, river mouth bar, frontal sheet sand and other microfacies. This new discovery is of great significance for oil exploration and production of the Neogene in Jiyang Depression.