A Late Pleistocene‐Holocene Record of Tropical Monsoon Climate from Groundwater Noble Gases and Isotopes in the Leizhou Peninsula, Southern China

Abstract Groundwater from the Leizhou Peninsula in tropical South China provides one of the first noble‐gas based paleoclimate reconstructions from the East Asian monsoon region. Radiocarbon dating establishes a robust chronology spanning the Late Pleistocene to the Holocene. Noble gas temperatures reveal a minimum glacial‐to‐Holocene warming of ∼5°C–6°C, consistent with global low‐latitude groundwater records. Stable isotopes (δ 18 O) covary with excess air, indicating that they primarily reflect monsoon‐driven precipitation changes rather than temperature. These records point to suppressed recharge during the Last Glacial Maximum, a short‐lived weakening of the summer monsoon during the Younger Dryas, and intensified precipitation in the early Holocene. By jointly resolving temperature and precipitation signals, fossil groundwater offers a dual constraint on tropical paleoclimate that complements existing continental records and provides benchmarks for testing climate model sensitivity in East Asia.