Pedo-chemical climate proxies in Late Pleistocene Serbian–Ukranian loess sequences

The last glacial–interglacial loess–paleosol sequences of Serbia and Ukraine provide a good climate reconstruction potential for this part of Europe. Four loess sections distributed over an area with present-day moist to semi-arid climates were studied. In addition to traditional paleoclimate proxies, such as grain-size distribution as proxy for wind-strength and source aridity, and magnetic susceptibility as proxy for precipitation (and temperature), pedo-chemical elemental ratios, obtained by selective sediment leaching procedures, function as sensitive recorders of variations in weathering intensity due to changes in precipitation and temperature. Especially, the earth alkaline element ratios of Ba/Sr and Sr/Ca are subject to strong variations as a result of carbonate dissolution/precipitation and variable cation exchange capacity on clay minerals along the elemental sequence of Ca–Sr–Ba. As shown by the close similarity to the magnetic susceptibility records in the different loess sections, these ratios reflect the effects of weathering intensity as a result of precipitation changes. The fact that Ba/Sr unequivocally shows higher values in both soils and paleosols in the four studied sections over the present-day climate gradient, singles this elemental ratio out as an interesting paleoclimate proxy.