Little Ice Age versus Present Day: Comparison of Temperature, Precipitation and Seasonality in Speleothem Records from the Han-sur-Lesse Cave, Belgium.

Abstract:

The Proserpine stalagmite is a 2 m large, tabular-shaped speleothem located in the Han-sur-Lesse cave in Belgium. The speleothem formed over the last 1000 years and is still growing. High-accuracy U/Th datings have indicated exceptionally high growth-rates of up to 2 mm per year. This, together with a well expressed annual layering, makes the Proserpine stalagmite an ideal candidate for high-resolution paleoclimate reconstructions of the last millennium.

Previous work, including over 10 years of cave monitoring, has already learned us how short-term, i.e. decadal to seasonal, climate variations are incorporated within speleothem calcite from the Han-sur-Lesse cave system. It has been shown that δ¹⁸O and δ¹³C stable isotopes and trace element proxies of recently formed calcite reflect seasonal variations in temperature and precipitation of the near-cave environment (Verheyden et al, 2008; Van Rampelbergh et al., 2014).

Now, this knowledge was used to infer local climate parameters further back in time to the period of +/- 1620-1630 CE, corresponding to one of the cold peaks within the Little Ice Age. Speleothem calcite was sampled at sub-annual resolution, with approximately 11 samples per year, for stable isotope analysis. LA-ICP-MS and µXRF analyses resulted in time series of trace elements. Preliminary results indicate a well expressed seasonal signal in δ¹³C and trace element composition but a multi-annual to decadal trend in δ¹⁸O. This combined proxy study eventually enables comparison of the expression of seasonality and longer term climate variations between a Little Ice Age cold peak and Present Day.

References:

Verheyden, S. et al., 2008, Monitoring climatological, hydrological and geochemical parameters in the Père Noël cave (Belgium): implication for the interpretation of speleothem isotopic and geochemical time-series. International Journal of Speleology, 37(3), 221-234.

Van Rampelbergh, M. et al., 2014, Seasonal variations recorded in cave monitoring results and a 10-year monthly resolved speleothem δ¹³C and δ¹⁸O record from the Han-sur-Lesse cave, Belgium. Climate of the Past, 10, 1-15, 2014.