Paleoenvironmental Evolution and Sea-Level Changes in the Central South Yellow Sea since Late Pleistocene: Evidence from Benthic Foraminifera and AMS14C Dating

Accurate chronology is critical for reconstructing marginal sea paleoenvironments, yet the impact of dating material selection remains underaddressed. This study presents benthic foraminiferal, lithological, and AMS14C data from the 5.73 m core T7-2 (central South Yellow Sea) to resolve late Pleistocene-Holocene environmental changes. A total of 119 benthic foraminiferal species were identified, with five assemblages reflecting sequential environmental transitions. Chronological results highlight a key dating strategy: benthic foraminifera reliably date the undisturbed upper section (<365 cm), while plant materials (especially seeds) are preferred for the transgression-disturbed lower section (>365 cm) to avoid reworking-induced age overestimation. Four environmental stages are identified: (1) a late Pleistocene nearshore environment (573-365 cm, ~12.69-13.02 cal kyr BP) with stagnant sea level (~13000 cal kyr BP), characterized by low foraminiferal abundance and euryhaline species dominance; (2) a transitional estuary environment (365-293 cm, ~9.64-12.69 cal kyr BP) overlapping the Younger Dryas event, where estuary species Cribrononion subincertum indicates low salinity environment; (3) an early Holocene shallow marine environment (293-269 cm, ~8.16-9.64 cal kyr BP) with enhanced Buccella frigida indicates the formation of cold water mass; (4) a middle to late Holocene marine environment (269-0 cm, ~0.41-8.16 cal kyr BP) with high foraminiferal abundance and Ammonia ketienziensis dominance, corresponding to high sea level. Two rapid sea-level rise events (MWP-1C: 9.14-9.64 kyr BP; MWP-1D: 8.16-7.66 kyr BP) are confirmed, driving water depth deepening. This study clarifies the South Yellow Sea’s response to global climate events and emphasizes tailored dating material selection for disturbed strata, providing new insights into marginal sea sea-level and coastal current dynamics.