Quantifying kinetic fractionation in Bunker Cave speleothems using Δ47

► We investigate kinetic isotope fractionation in speleothems using clumped isotopes. ► Clumped isotopes are a sensitive quantitative measure for kinetic fractionation. ► Variability in the kinetic fractionation is not related to growth rate. ► Kinetic isotope fractionation is mainly influenced by super saturation and PCP. ► Δ47 helps to distinguish internal (kinetic) from external (climatic) forcings.