The quantitative evaluation of sublimation and the estimation of original hydrogen and oxygen isotope ratios of a firn core at East Queen Maud Land, Antarctica

The quantitative evaluation of sublimation during firnification and the estimation of original hydrogen and oxygen isotope ratios of deposited snow were attempted by a simultaneous measurement of δD and δ 18 O values in a firn core having well-developed depth hoar collected at East Queen Maud Land, Antarctica. The d-parameter of the core ranged from 11 to 18 and showed good positive correlation with the depth hoar level suggesting that the increase in the d-parameter from 10 was caused by post-depostional firnification in which sublimation plays an important role. Based on the d-parameters, the firn was estimated to have lost 30-35% of deposited snow during firnification and to be enriched in deuterium and oxygen-18 by about 50 and 6 ‰, respectively, relative to the deposited snow.