Quantitative Analysis of Source-to-Sink Systems: A Case Study of the Paleogene in the Laizhouwan Sag, Southern Bohai Bay Basin

Quantitative reconstruction of source-to-sink (S2S) systems provides insights into sediment dispersal in continental rift basins. However, relationships among source-area geometry, sediment-routing architecture, and downstream depositional development remain difficult to constrain in structurally heterogeneous settings. This study integrates three-dimensional seismic data, well logs, core observations, and petrographic data to investigate Paleogene S2S systems in the southern Laizhouwan Sag, Bohai Bay Basin. Effective source areas range from 10.0 to 98.5 km2 across the investigated stratigraphic intervals. Sixteen principal sediment-routing pathways are identified, with mapped lengths of approximately 4.6–18.4 km. Measurements from 34 depositional-area records indicate slope gradients of 0.96–4.76°. Two end-member S2S architectures are recognized. Fault-controlled steep margins are characterized by structurally confined pathways and proximal fan-delta deposition, whereas gentler margins contain more extensive routing networks associated with braided-river-delta development. Variations in depositional-body dimensions are examined in relation to source-area geometry, routing morphology, and basin-margin configuration. These dimensions record preserved sediment accumulation rather than directly measured sediment flux. The results provide a quantitative framework for evaluating S2S configurations in rift-lake basins while highlighting uncertainties associated with paleogeomorphic reconstruction, temporal matching, and sediment preservation.