MICROTUS GUENTHERI AS A CLIMATE PROXY FOR THE MIDDLE PLEISTOCENE LEVANT: EVIDENCE FROM CARBON STABLE ISOTOPE ANALYSIS

Climate oscillations during the Last Glacial Period (LGP, c. 115,000– 11,700 BP) in regions such as the Levant are not as pronounced as they are in northern regions such as North America or Europe, with one of the main questions being whether the LGP in these areas was cold and humid or cold and dry. This study uses carbon isotopes from rodent teeth as a proxy for climate change to reconstruct the paleoenvironment of the Middle Pleistocene Levant at multiple archaeological sites.

While carbon isotopes are most commonly used to differentiate between C₃ and C₄ plants, mid-latitudes are dominated by primarily C₃ vegetation, therefore precipitation causes the variations in δ¹³C levels. To develop the start of a modern model of the Levant’s paleoecology, Microtus guentheri teeth were selected from three Israel archaeological sites, Rantis Cave (~160 Kya), Hayonim Cave (~160 Kya), and Amud Cave (~45 Kya), which were sent to the University of Arkansas’ stable isotope laboratory for analysis.

The results of this analysis were compared statistically with a correlation of modern Microtus guentheri samples and GIS-derived climatic data which indicated a positive correlation between δ¹³C and mean annual rainfall. These results build upon a preliminary study of previous carbon stable isotope analyses of Amud (n=20, mean δ¹³C -7.96 ± 0.46) and Rantis (n=9, -9.8, mean δ¹³C ± 0.25), that indicates the LGP environment of the Levant was a cold and humid environment rather than cold and dry, with an increase in mean annual precipitation compared to the climate in the Levant today. Furthermore, this data demonstrates the value of using rodents as a means to detect climatic shifts in mid-latitude regions, despite having less-pronounced oscillations.