Collaborative Research: Reconstruction of Late-Quaternary Paleotemperatures Across the European Loess Belt

Quantitative estimates of past temperature changes in continental interiors are important for reconstructing regional and local climatic responses to changing atmospheric conditions during the glacial-interglacial cycles of the Quaternary Period. Recent developments in amino acid geochronology and paleothermometry, combined with improvements in dating methods, offer the potential for quantitatively estimating precise paleotemperatures and paleotemperature gradients across the European continent for specific intervals of time since the last interglacial warm period.

Paleotemperatures in the region traditionally have been estimated based on modern climatic analogues of fossil assemblages collected from loess sediments. Such methods are limited by our knowledge of the present environmental ranges and past distributions of specific elements of the fossil fauna or flora. We propose, however, to apply a uniform biogeochemical paleothermometer based on the temperature-controlled amino acid racemization reaction in the quantitative reconstruction of paleotemperatures across the region.

This research aims to provide a systematic reconstruction of a high quality record of paleotemperatures and paleotemperature gradients over the last approximately 70,000 years across Europe. We propose to do a detailed collection and amino acid analysis of fossil gastropod shells from loess deposits of the last glacial period at selected sites in a west-to-east transect across Europe. The specific objectives of this research are 1) to measure the extent of amino acid racemization in fossil gastropod shells collected from loess localities ranging from northern France, across western and central Europe, and into the highly continental region of the eastern European loess plains; 2) to determine independent ages of the fossil shells or enclosing loess sediment using radiocarbon and luminescence dating methods; 3) to quantitatively estimate paleotemperatures and paleotemperature gradients for selected intervals of time through the last glacial cycle across the region based on the chronological data and amino acid racemization measurements in fossil gastropod shells; and 4) to quantify the relationship between effective ground temperatures, which drive the racemization reaction, and surface air temperatures, which are critical data in the reconstruction of past changes in terrestrial climate. It is expected that this research will enhance our knowledge of how climate has evolved across the European continent since the last interglacial period which ended approximately 70,000 years ago.

This research is a collaborative project between William D. McCoy of the Department of Geosciences, University of Massachusetts, Amherst, and Eric A. Oches of the Department of Geology, University of South Florida, Tampa. McCoy is primarily responsible for the field measurements of ground temperature and modeling the relationship between ground temperature and effective temperatures controlling the amino acid racemization reaction. Oches is responsible for the measurements of the extent of amino acid racemization in the fossil shells, modeling the kinetics of the racemization reaction for multiple amino acids in different genera of gastropods, and the calculation of paleotemperatures for discrete intervals of time. Field work will be conducted jointly.

UMass Climate System Research Center Staff:

William D. McCoy