Stable isotopes in small mammal dental carbonate: investigating their applications for reconstructing Quaternary climate variability in the UK

Past Life and Environments

RHUL

RHUL

The oxygen isotope analysis of fossil mammalian teeth is a well-established technique for palaeoclimate reconstruction. However, the utilization of this technique for understanding seasonal temperature changes during the Quaternary period has thus far been fairly limited. Recent studies have highlighted the potential for using oxygen isotopes in small mammal teeth as a proxy for past climatic conditions. However, the relationship between the oxygen isotope compositions of rodent teeth and local climate, and the factors that can influence this relationship, are poorly understood. Establishing a robust modern calibration between oxygen isotopes in rodent teeth and climate would enable quantitative palaeoclimate reconstructions to be generated for sites that are rich in fossil teeth, such as river and cave sequences. Moreover, Grimes et al. (2003) proposed a novel approach for quantitatively reconstructing past summer temperatures, through coupling the oxygen isotope values of rodent teeth and coeval freshwater biominerals. As yet, however, this method has not been tested for multiple Quaternary sites, despite the abundance of fossil remains available for analysis. This research consequently aims to: 1) investigate the sources of isotope variability in modern rodent populations across Britain, 2) establish a modern fractionation equation relating oxygen isotope compositions of rodent teeth and local meteoric water, 3) test whether the coupled oxygen isotope analysis of rodent teeth and freshwater shell carbonates can produce reliable temperature estimates for past interglacial stages in Britain, and 4) examine whether millennial-scale climatic fluctuations can be identified in the isotopic compositions of rodent teeth derived from 2 cave sedimentary sequences in Britain.

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