70 years of northern Victoria Land (Antarctica) accumulation rate

Abstract

Measurements of oxygen isotope ratio (δ18O), major anions and cations, insoluble dust and tritium were performed every 4-6 cm along the Hercules Neve (northern Victoria Land, Antarctica) 22 m firn core. Concentration/depth profiles for H2O2, methane sulphonic acid and non-sea-salt sulphate (nssSO42-) were used to obtain a dating for the core by a multiparametric method involving a normalisation procedure and a linear combination of original profiles. This dating was compared with the δ18O and dust records to obtain a reliable identification of successive annual snow layers. The time-scale obtained from the seasonally varying signals was confirmed by an absolute date obtained from the 1965 thermonuclear atmospheric bomb test tritium peak. Around 70 years (1926-94) of annual accumulation rate data were obtained from the core. δ18O variations recorded along the core may be ascribed to seasonal variations of this parameter related to temperature variations.