Six-year record of oxygen and hydrogen isotope variations in South Pole firn

Abstract

Direct measurements of snow accumulation at stakes near the South Pole over a 6-year period (1958–1963) provide an unusual opportunity to check the reliability of accumulation and annual-layer determinations by stratigraphic and isotopic methods. The results are gratifying. Agreement between interpretations based on stratigraphic and isotopic data is excellent, and both are consistent with accumulation-stake measurements in nearly all respects. All three procedures indicate an average annual accumulation of 7 cm of water at the South Pole over the 1958–1963 interval. Isotope data suggest that depth-hoar formation may result in relative enrichment in O^(18). This could come about through partial recondensation of vapor generated within the depth-hoar layer accompanied by escape of residual vapor impoverished in O^(18).