Dissolved Gas Paleotemperatures and ¹⁸O Variations Derived from Groundwater Near Uitenhage, South Africa

Abstract

Under the near-ideal hydrologic conditions provided by the Uitenhage artesian aquifer, reliable estimates of paleotemperatures were obtained by measurement of the dissolved N 2 and Ar in groundwater, confidently dated in the range 28,000 yr B.P. to the present using 14 C. The mean annual air temperature in this area during the last glaciation is calculated to have been, on average, 1/2°C lower than during the Holocene. The change in the 18 O/ 16 O ratio of the groundwater, corrected for changes in ocean water, amounted to 0.4‰ per °C.