Article révisé par les pairs
Résumé : Sodium, magnesium, potassium, calcium, iron, manganese and nickel were measured in firn samples from Base Roi Baudouin (BRB, 70°S, 24°E), Amundsen-Scott Station (ASS, 90°S) and Plateau Station (PLA, 79°S, 40°E). The rates of snow accumulation at the three stations are respectively, in : 40, 6 and 2.8. The analyses were carried out by neutron activation, atomic absorption and isotope dilution. In most cases, Fe, Mn, Ni were measured simultaneously by two or three methods on aliquots of the same sample. The corrections for contamination never exceeded 10%. Average concentrations found at BRB (5 samples, 14 kg total) and at PLA (4 samples, 32 kg) respectively are as follows, in p.p.b.: Na 250-30; Mg 29-5; K 29-5; Ca 17-8; Mn 0.1-0.35; Fe 6-7; Ni 0.36-0.08. At AAS (2 samples, 3 kg) : Na 9; Mn 0.2; Ni 0.1. On account of the everpresent possibility of contamination, these values must be considered as upper limits. The following conclusions are drawn from the results: 1. 1)