The sedimentary characteristics of paleogene conglomerates and their sedimentary dynamics in source-to-sink system in the langgu sag

Abstract

Under the guidance of sedimentary dynamics of source-to-sink system, the sedimentary characteristics of Paleogene conglomerates in the Langgu Sag are studied; the paleogeomorphology is restored from the three aspects of highs, basin controlling faults, and sag; and the paleo-provenance is restored based on the paleogeographic evolution. According to the lithology, sedimentary structure, and vertical sequence of the Daxing conglomerate, as well as the source composition and paleomorphological features of the conglomerate sediments, the Daxing conglomerate resulted from three types of depositional models: fault-trough gravity flow, debris flow nearshore subaqueous fan, and mudslides nearshore subaqueous fan. The physical properties and oil and gas production capacity of the debris flow nearshore subaqueous fan are obviously better than those of the other two types of conglomerate bodies, and that have been confirmed by exploration practice.