NOAA/WDS Paleoclimatology - Cold Air Cave Geochemical Data from 4400 to 470 Cal Yr BP

Stable isotope analyses of a uranium-series-dated stalagmite from South Africa provide a record of climate changes for the periods 4400–4000 years and ∼800 years ago to recent, interrupted by a prolonged growth hiatus. Generally enriched stable oxygen isotope values, interpreted here to indicate more humid conditions, occurred around 800 years ago. Subsequently a marked depletion in oxygen and carbon isotope values occurred about 600 years ago, reflecting, we believe, shifts toward drier, cooler conditions as the regional indication of the Little Ice Age. This period with depleted, yet oscillating isotope values, is replaced by a period with enriched isotopes until recent times. The record is notable for sharp shifts in isotopic values, on the scale of decades, which reflect rapid oscillations in local climate conditions.