Lead isotope evidence for Antarctic Ice Sheet changes in the Weddell Sea sector since the Last Glacial Maximum

The Weddell Sea influences global ocean circulation and sea level through modulating Antarctic Bottom Water formation and Antarctic Ice Sheet discharges, but the history of ice‐sheet dynamics in this region remains poorly constrained due to limited well‐dated geological records. To provide a new geochemical perspective on ice‐sheet dynamics since the Last Glacial Maximum (LGM), this study presents paired authigenic and detrital Pb isotope records from sediment core PS1599‐3 recovered from the continental slope north of the Filchner Trough. Comparison with Antarctic Pb isotope provinces indicates that both detrital and authigenic Pb signatures were possibly sourced from a Shackleton Range‐like region in the south‐eastern Weddell Sea sector of East Antarctica. This suggests that dominant upstream drainage sources remained broadly stable throughout the last ~23 ka. We interpret the downcore Pb isotope variations to primarily reflect changes in the delivery of subglacial weathering‐derived Pb associated with grounding‐line dynamics in the Filchner Trough. Authigenic ²⁰⁶ Pb/ ²⁰⁴ Pb ratios show a sharp increase at ~23 ka, followed by two decreases at ~20 and 11–9 ka. We suggest that a re‐advance of grounded ice near the LGM was followed by initial retreat at ~20 ka and further grounding‐line retreat or reorganization during the Early Holocene. These findings highlight the use of authigenic Pb isotopes as potential tracers for reconstructing polar ice‐sheet dynamics and meltwater influences.