CLIMATE AND GROUNDWATER RECHARGE DURING THE LAST GLACIATION IN AN ICE-COVERED REGION

A multitracer study of a small aquifer in northern Switzerland indicat es that the atmosphere in central Europe cooled by at Least 5 degrees C during the Last glacial period. The relation between oxygen isotope ratios (delta(18)O) and recharge temperatures reconstructed for this p eriod is similar to the present-day one if a shift in the delta(18)O v alue of the oceans during the ice age is taken into account. This simi larity suggests that the present-day delta(18)O-temperature relation c an be used to reconstruct paleoclimate conditions in northern Switzerl and. A gap in calculated groundwater age between about 17,000 and 25,0 00 years before the present indicates that during the Last glacial max imum, local groundwater recharge was prevented by overlying glaciers.