Summary: East Antarctic ice core sulfur isotope measurements over a complete
and M. H. Thiemens
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California, USA
J. Farquhar and A. J. Kaufman
Earth Systems Science Interdisciplinary Center and Department of Geology, University of Maryland, College Park,
J. Savarino and R. J. Delmas
Laboratoire de Glaciologie et Ge´ophysique de l'Environnement, St. Martin d'He`res, France
Received 19 February 2003; revised 11 June 2003; accepted 28 August 2003; published 24 December 2003.
 Both sulfur and oxygen isotopes of sulfate preserved in ice cores from Greenland
and Antarctica have provided information on the relative sources of sulfate in the ice
and their chemical transformation pathways in the atmosphere over various time periods.
The mass-independent fractionation in the oxygen isotopes of sulfate from the Vostok
ice core from east Antarctica suggests that gas-phase oxidation by the hydroxyl radical
(OH) was relatively greater than aqueous-phase oxidation by O3 and H2O2 during the
last glacial period than during the Eemian and preindustrial Holocene. The complete
sulfur isotopic composition (d33