Western Russia has warmed at nearly twice the global rate over the past century; however, despite it being a major center of agricultural production, the hydrological response to such warming has not been well constrained. This investigation analyzes Mg and Sr variations in a U-Th dated stalagmite from the Volga Basin of the Southern Ural Mountains, which were interpreted to reflect local precipitation and water residence time from roughly 11,700 to 1,800 years BP. Pollen data indicate that the modern and forested landscape has been in place for roughly 10,000 years, and this vegetation has been the major source of carbon for the underground caves. Previously reported ä13C values of our cave were interpreted to reflect changes in warm-season precipitation. Such changes support the Mg data, and suggest a drying trend during the last four centuries of stalagmite growth. Previous isotope data reveal that ä18O tends to slowly increase, which suggests the region has gradually warmed since the beginning of the Holocene. Precipitation changes have not been as continuous; moreover, the chemical ratio data suggest that the Volga climate became increasingly humid following the Younger Dryas, stayed relatively wet throughout the Holocene climatic optimum, and has progressively become drier ever since. Unprecedented warmth and dryness in the future climate threatens agricultural sustainability in otherwise fertile lands, which majorly affects populations that depend on Russian food production.
Stefano Garcia Riefkohl, ’16
Sponsor: Jonathan Baker