Rapid Bølling-Allerød Interstadial deglaciation in the southeastern Tibetan Plateau: Evidence from ¹⁰Be chronology of the glacially polished bedrock surfaces in the Haizishan Plateau

The timing and pattern of abrupt climatic events during the last glacial termination, particularly the Bølling-Allerød (B-A) Interstadial, are critical for understanding rapid climate transitions under global warming. Well-preserved glacial landforms on the Tibetan Plateau (TP) provide valuable insights into past climate change, yet glacier responses to the B-A Interstadial remain poorly constrained due to limited chronological data. Here, we report ten new ¹⁰Be surface exposure ages from glacially polished bedrock along the main ice-flow path in the Lahaku Valley, Haizishan Plateau (HZSP), southeastern TP. The results cluster tightly between 15.1±0.9 ka and 13.7±0.9 ka, with a mean of 14.3±0.5 ka, indicating a rapid deglaciation at the onset of the B-A Interstadial. These ages, combined with published ¹⁰Be ages in the HZSP, provide robust evidence for B-A deglaciation on the TP. Furthermore, this rapid deglaciation aligns with similar events observed across the Northern Hemisphere, pointing to a common hemispheric-scale climatic forcing. Comparative analysis of glacial and climatic records indicates that the primary driver was likely abrupt warming, linked to ocean-atmosphere processes associated with a reinvigorated Atlantic Meridional Overturning Circulation.