SEDIMENT LOADING AT THE YELLOW RIVER DELTA: MODELING DEPOSITIONAL DYNAMICS AND IMPACT ON REGIONAL SEA LEVEL

The evolving pattern of sedimentation on the continental shelf reflects not only the influence of glacial cycles on soils, erosion, river loads, and water discharges, but also the local sea-level history as it is perturbed by the sediment redistribution. Sediment deposition at large river deltas influences sea level by introducing a load that perturbs crustal elevation and the gravitational field. These sediment loads vary in space and time over glacial cycles, as deltas prograde during sea-level highstands and shelves are exposed during lowstands. The Yellow River serves as an archetypical case study of the fluvial response to glacial cycles. Draining the highly-erodible, glacially-derived Loess Plateau, its sediment load is the second highest in the world, and it has avulsed frequently over the Shandong Peninsula, leaving behind spatially distinct depocenters. The region thus provides an ideal setting for modeling sediment loads and investigating how glacial cycles control sedimentation history and regional sea level. We reconstruct sediment redistribution using physical data recorded in dated sediment cores, seismic sections, and river flux measurements. The combined depositional and erosional history is then incorporated into a gravitationally self-consistent global model of glacial isostatic adjustment to explore how the evolving sediment load and migrating depositional center impact local crustal elevations and gravity, and thus sea level, over glacial timescales. Finally, we will also consider the implications of these new, sediment-corrected sea-level predictions for inferences of global-scale ice volumes through the last glacial cycle.