High-resolution proxy records from two simultaneously grown stalagmites from Zoolithencave (southeastern Germany) and their potential for palaeoclimate reconstruction

Abstract

Two small annually laminated stalagmites from Zoolithencave (southeastern Germany) grew between CE 1821 and 1970 (Zoo-rez-1) and CE 1835 and 1970 (Zoo-rez-2), respectively. Trace element concentrations were determined by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Samples for δ13C and δ18O analyses were micromilled on annual and subannual resolution. Soil and host rock samples were analyzed by X-Ray Diffraction (XRD) and their elemental concentrations determined via inductively coupled plasma optical emission spectrometer (ICP-OES). Trace element concentrations in the stalagmites show two groups in the principal component analyses: one with Mg, Ba, and Sr and another with Y, P, and Al, respectively. The second group reflects the content of detrital material. Increased weathering of soil minerals seems to have a strong influence on the silicate/carbonate weathering ratio controlling the variability of Mg, Ba, and Sr. Meteorological and Global Network of Isotopes in Precipitation (GNIP) station data were used to calculate the δ18O values of the drip water (infiltration-weighted, mean annual, and the mean of the winter precipitation δ18O values) as well as the corresponding speleothem calcite. The δ18O values calculated by the infiltration-weighted model show similar patterns and amplitudes as the measured δ18O values of the two stalagmites. This suggests that the δ18O values of speleothem calcite reflect the δ18O values of infiltration-weighted annual precipitation, which zis related to mean annual temperature, resulting in a significant correlation between mean annual temperature and the measured δ18O values of stalagmite Zoo-rez-2. This relationship could potentially be used for quantitative climate reconstruction in the future by extending the time series back in time with further stalagmites from Zoolithencave.