Straits are narrow marine gateways whose sediment-dispersal systems are unusually sensitive to sea-level change: small shifts in water depth and cross-sectional area reorganize the through-flowing currents that redistribute river-derived sediment. Integrating sediment-core, seismic and provenance data from three studies, we compare the Holocene evolution of two straits on the Chinese continental margin, the Taiwan and Bohai Straits, to show how post-glacial sea-level rise governs their contrasting sediment-dispersal patterns.
In the Taiwan Strait, deglacial flooding submerged the Taiwan Bank and established the northward-flowing Taiwan Strait Current, creating an ocean-current-dominated setting. Two river-fed dispersal paths developed on opposite margins: the mainland-sourced Changjiang Coastal Mud Belt, one of the largest such belts on Earth, and a Choshui-fed muddy contourite drift that the current progressively detached from the Taiwanese coast. Across the last sea-level cycle, rising and falling sea level drove the mud belt landward and seaward, switched its provenance among the Changjiang, Minjiang and Taiwan, and left cryptic hiatuses within a deceptively continuous muddy succession.
The Bohai Strait, by contrast, is a mixed-energy, strongly asymmetric system. A three-stage Holocene evolution, driven by transgression and repeated Yellow River avulsions, produced a deep, tide-dominated, sediment-starved northern channel with a large flood-tidal delta beside a shallow, supply-dominated southern margin that captures the Yellow River load and exports mud to the Yellow Sea, generating pronounced transverse and longitudinal asymmetries.
Together, the two straits span a spectrum from ocean-current-dominated and quasi-symmetric (Taiwan) to tide- and supply-dominated and strongly asymmetric (Bohai), yet share one master control: relative sea-level rise since the last deglaciation, which floods and widens the passages, strengthens their currents, and through coupled current reorganization and river avulsion, reroutes sediment in threshold-like, nonlinear steps. These Holocene strait archives refine facies models for straits and seaways and provide a natural experiment for anticipating sediment redistribution along today's rapidly changing coasts.