广东海陵湾全新世沉积特征及其古环境响应OA

Coastal environmental changes resulting from global climate change has significant implications for regional development.Hailing Bay,located in the northern South China Sea,preserves a continuous Holocene sedimentary archive,making it ideal for reconstructing paleoenvironmental evolution.This study examined the offshore HLZZ08 core and established a chronological framework using radiocarbon(14C)and optically stimulated luminescence dating.Grain-size parameters were used to build sedimentary sequences.End-member modeling,grain-size standard deviation analysis,and principal component analysis were applied to explore the relationship between grain-size variability and regional environmental change.The sediment grain size distributions in core HLZZ08 are primarily unimodal to bimodal,indicating multi-stage shifts in depositional dynamics.The fine-grained components reflect variations in summer monsoon intensity and fluvial discharge,whereas the coarse-grained fractions correspond to stronger fluvial and marine hydrodynamic conditions during lower sea-level periods.Grain-size variations reveal a strengthening summer monsoon in the early Holocene,followed by a progressive weakening in the mid-Holocene,with depositional dynamics primarily controlled by monsoon intensity and sea-level fluctuations.Over the past 2 000 years,the sedimentary evolution shifted from being monsoon-dominated to sea-level-controlled.During this period,fine particles remained sensitive to summer monsoon variability,while coarse particles primarily tracked sea-level changes.Concurrently,grain-size fluctuations over the last millennium have also shown a degree of synchrony with regional indicators of human activity.These findings provide new insights into Holocene environment-human interactions in Hailing Bay and advance paleoenvironmental research in the northern South China Sea.