Depositional characteristics of the subaqueous gravity flow deposits from the Cretaceous Taoqihe Formation in the Sunwu-Jiayin Basin, Heilongjiang

The present paper gives a detailed description of the depositional characteristics of the subaqueous gravity flow deposits from the Cretaceous Taoqihe Formation in the Sunwu-Jiayin Basin, Heilongjiang on the basis of outcrops, cores, well logs and thin section examination. The subaqueous gravity flow deposits from the Cretaceous Taoqihe Formation are interpreted as the sublacustrine fan deposits widespread in the study area, and may be subdivided into three sedimentary subfacies including the inner fan, middle fan and outer fan subfacies, and five sedimentary microfacies including the main channel, outer main channel, braided channel, braided interchannel and distal turbidite microfacies. The inner fan is blanketed by the subaqueous debris flow deposits; the middle fan is composed of the liquefied flow deposits and turbidity deposits, and the outer fan is dominated by turbidites. It is inferred from the seismic profiles that the faulting operating during the deposition of the Taoqihe Formation during the Cretaceous should be responsible for the formation and development of the sublacustrine fan deposits.