Hypogenic Overprinting, Radionuclide Activity and Diurnal Ventilation: Redrawing the Foundations of Speleothem-Based Paleoclimate Reconstructions Mike Buchanan 2025 Abstract Cave microclimates are traditionally seen as stable environments with minimal thermal variability and predictable airflow patterns. However, this perspective fails to account for disruptive forces such as hypogenic supersaturation events, radionuclide-induced speleogenesis and nuanced diurnal ventilation. These karst system phenomena not only influence cave morphology and microclimate but also undermine the foundational assumptions of isotopic speleothem dating. This paper integrates emerging research and empirical observations to argue that many speleothem-based paleoclimate reconstructions may rest on compromised stratigraphic and isotopic frameworks. Introduction Caves are considered ideal archives of paleoclimate by some due to their stable environments and alleged ability to preserve...