An Oxygen isotope record of lacustrine opal from a European Maar indicates climatic stability during the last interglacial

The penultimate temperate period, 127110 ka before present (BP), bracketed by abrupt shifts of the global climate system initiating and terminating it, is considered as an analogue of the Holocene because of a similar low global ice-volume. Ice core records as well as continental and marine records exhibit conflicting evidence concerning the climate variability within this period, the Last Interglacial. We present, for the first time, a high-resolution record of oxygen isotopes in diatom opal of the Last Interglacial obtained from the Ribains Maar in France (44ø50'09"N 3ø49'16"E). Our results indicate that the Last Interglacial in southwestern Europe was generally a period of climatic stability. The record shows that the temperate period was initiated by an abrupt warm event followed midway by a minor climatic transition to a colder climate. An abrupt isotopic depletion that occurs simultaneously with abrupt changes in pollen and diatom assemblages marks the end of the temperate period, and is correlative with the Melisey I stadial. Variations in the isotopic composition of lake-water related to the isotopic composition of precipitation and evaporation dominate the biogenic opal oxygen isotope record.