Litnited tnigration of soluble ionic species in a Siple Dotne , Antarctica , ice core

High-resolution (> 10 samples a I) glaciochemical analyses covering the las t 110 years from a Siple Dome, Antarctica, ice core reveal limited migration of certa in soluble ionic species (methane sulfonic acid, N03 and Mg +). The obse rved chemical migration may be due in part to seasonal alternation be tween less acidic winter (from high sea-salt concentrations) and more acidic summer (from high marine biogenic acid concentra tions) layers, common at coasta l sites such as Siple Dome. Exact mechanisms to explain the migration are unclear, although simple diffusion and gravita tional movement a re unlikely since new peaks are formed where none previously existed in each case. Initia l migration of each species is both shallower and ea rli er at Siple Dome than at othcr sites in Antarctica where simila r phenomena have been observed, which may be related to the relatively low accumulation rate at Siple Dome ("-'13.3 cm ice aI). Migration appears to be limited to either the preceding or following seasonal layer for each species, suggesting that paleoclim atic interpretati ons based on data with lower than annua l resolution a re not likely to be affec ted .