Terrestrial molluscs as indicators of global aeolian dust fluxes during glacial stages

Abstract

This paper represents an approach to discerning the kind of climatic signal that land snails might record. The study uses previous analyses of the Achenheim molluscs, whose time series can be compared with ice-core records or marine records. Terrestrial molluscs are characteristic of the environment in which they live, mainly mirroring prevailing climate and vegetation. As a result of this relatively close connection between biotope and mollusc assemblages, reconstructions of past environments can be made that agree generally with results from pollen analyses. In this way, malacofaunas in loess sections permit determination of environmental variability and climatic change. Loess deposits, however, correspond to a particular environment. Decreasing or increasing dust deposition affects the molluscan assemblages by altering the environmental conditions for better or for worse. The variation in the mollusc diversity index in Achenheim shows a striking correspondence with dust-flux variation. There is only a low correlation between diversity index and temperature, precipitation or moisture estimates.