Carbon and nitrogen stable isotope analysis of northwest European horse bone and tooth collagen, 40,000 BP–present: Palaeoclimatic interpretations

Abstract

Carbon and nitrogen stable isotope ratios of bone and tooth dentine collagen from 142 horses were analysed to consider the potential of isotopic analysis of faunal remains as a palaeoenvironmental and palaeoclimatic proxy. A general trend through time towards lighter δ 13C values was observed, but with an obvious depletion at the Late Glacial/Holocene transition. Horse δ 13C values appear to track plant δ 13C. Although phenomenon such as the canopy effect may influence faunal δ 13C values, we believe that the influence on plants of increasing atmospheric CO 2 is the primary factor in the change in faunal δ 13C values at the Late Glacial/Holocene transition. A post-glacial depletion in horse δ 15N values is observed in areas proximal to glacial retreat although no data is available in these areas during the Last Glacial Maximum. Horse δ 15N values are presumed to reflect plant δ 15N values. Depleted plant nitrogen may be attributed to a number of factors e.g. water availability, temperature, cycling of nitrogen in the soil, soil nutrient availability (especially phosphorus in the post-glacial period), and the type of mycorrhizal associations formed with plant. These effects may be interrelated, and be linked such that a positive feedback can give a non-linear response to a single parameter.