Seismic-based sediment provenance analysis in continental lacustrine rift basins: An example from the Bohai Bay Basin, China

Abstract

By using recently acquired three-dimensional seismic data, a seismic-based sediment provenance analysis was conducted in the late Paleogene sequence of the western slope of the Bozhong sag, Bohai Bay Basin, where the main depositional center was between the Shaleitian uplift and the Shijiutuo uplift. Three styles of sediment-transport pathways were identified in the study area, including sediment transport via (1) faulted troughs, (2) incised valleys, and (3) structural transfer zones. The Paleogene deposits in the study area were primarily controlled by the faulted-trough pathways, which are northeast–southwest oriented in between different northeast–southwest-trending faults with sediments derived primarily from the Shaleitian uplift. The sediments to the east of the Shaleitian uplift were interpreted to have sourced via relatively long-distance transportation and deposited along the northeast–southwest-trending faulted troughs, forming a deltaic sediment belt. In contrast, sediments derived from the Shijiutuo uplift, which were transported by the incised-valley pathways and deposited in the southern margin of the uplift, formed proximal fan-deltas. The depositional systems in the study area are characterized by the coupling of source–faulted-trough pathway–deltaic–lacustrine deposits in the eastern margin of the Shaleitian uplift and that of source–incised-valley-pathway–fan-deltaic–lacustrine deposits near the southern margin of the Shijiutuo uplift. The proposed spatial distribution of the sand bodies extends the distribution range for potential reservoir sand bodies beyond the currently exploration area. This work may serve as a useful reference for sedimentary provenance analysis in other types of sedimentary basins.