Abstract:

 On the basis of well-loggings, seismics, cores data, the sandstone-body types of the block  Che 66 on the northern steep slope zone of Chezhen Sag in Jiyang Depression, were determined by geologically-synthesized methods, and the depositional boundaries of deep-water were also  made clear. With detailed observations and descriptions of cores, combined with geological and seismic profiles, and plane distributions of sedimentary facies studied, it was concluded that the sub-lacustrine fans and slide turbidite fans of the Lower Third Member of Shahejie Formation were developed in the block Che 66, interlayered within deep-water dark mudstones where characteristic sediments were the inner fan of the sub-lacustrine fans, within main-channels and inter-channels, medium- and fine-grained conglomerates of debris flows and mudstones of setting sediments. Longitudinally the upper of the member is mudstone-dominated and lower sandstone-dominated. The inner fan debris flows of lake fans were turned into the middle fan grain flows and turbidity flows of lake fans were from north to south, with sedimentary facies trend from near proximate to distal provenances. This proclaimed that the provenances were from the northern Chenzikou bulge.

Key words: sublacustrine fan, grain flow, slide turbidite fan, Chezhen Sag