Sulfur isotopic measurements from a West Antarctic ice core: implications for sulfate source and transport

Measurements of dS covering the years 1935–76 and including the 1963 Agung (Indonesia) eruption were made on a West Antarctic firn core, RIDSA (78.73 S, 116.33W; 1740ma.s.l.), and results are used to unravel potential source functions in the sulfur cycle over West Antarctica. The dS values of SO2� 4 range from 3.1% to 9.9%. These values are lower than those reported for central Antarctica, from near South Pole station, of 9.3–18.1% (Patris and others, 2000). While the Agung period is isotopically distinct at South Pole, it is not in the RIDSA dataset, suggesting differences in the source associations for the sulfur cycle between these two regions. Given the relatively large input of marine aerosols at RIDSA (determined from Na data and the seasonal SO2� 4 cycle), there is likely a large marine biogenic SO2� 4 influence. The dS values indicate, however, that this marine biogenic