CAN CAVE DEPOSITS IN NORTHERN SPAIN RECONSTRUCT THE NORTH ATLANTIC OSCILLATION?

Speleothems deposits offer a potential high resolution terrestrial record that might allow us to reconstruct rainfall and past behavior of the North Atlantic Oscillation (NAO). We will analyze cave hydrology and consider stalagmite geochemistry to explore potential relationships between trace elements and North Atlantic climate variability. We have 48 hour discrete drip water samples from Pindal Cave in Northern Spain (43.0o N, 4.5o W) from December 2003 through present. Analysis of drip water chemistry revealed strong correlations between the drip rate and Ca, Mg/Ca, and Sr/Ca (r2 values of 0.52, 0.48, and 0.56 respectively). The relationship between Pindal Cave’s drip rate and local meteoric precipitation is less clear on a weekly time scale due to temporary storage in intermediate reservoirs. Analysis of a cross-section of a recent actively growing stalagmite reveals an average growth rate of 0.6 mm/yr based on counting inferred annual layers. Mg/Ca and Sr/Ca ratios of estimated 57 year record show some coherent variation which may be related to precipitation. We will compare this record to local historical precipitation data as well as NAO data. We will also use a fossil stalagmite to search for longer amplitude changes in Sr/Ca and Mg/Ca.