High-resolution (>10 samples a I) glaciochemical analyses covering the last 110 years from a Siple Dome, Antarctica, ice core reveal lim ited migration of certain soluble ionic species (m ethane sulfonic acid, N03 and Mg2+). Th e observed ch emical migration may be due in part to seasonal alternation between less acidic winter (from high sea-salt concentrations) and more acidic summer (from high marine biogenic acid concentrations) layers, common at coastal sites such as Siple Dome. Exact

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... isms to explain the migration are unclear, although simple diffusion and gravitational movement are unlikely since new peaks are formed where none previously existed in each case. Initial migration of each species is both sh allower and earlier at Siple Dome th an at oth er sites in Antarctica where similar ph enomena have been observed, wh ich may be related to th e relatively low accumulation rate at Siple Dom e ("-'13.3 cm ice a-I). Migration appears to be limited to eith er th e preceding or fol lowing seasonal layer for each species, suggest­ ing that paleoclimatic interpretations based on data with lower than annual resolution are not likely to be affected.