Volcanic gas emissions from Mount Erebus and their impact on the Antarctic environment

Emission rates of SO2, HCl, and HF from the active volcano Mount Erebus Antarctica, increased between 1986 and 1991; SO2 from 7.7 to 25.9 Gg yr(-1), HCl from 6.9 to 13.3 Gg yr(-1) and HF from 4.0 to 6.0 Gg yr(-1). The emission rates of halogens from Mount Erebus are high relative to SO, emissions and are accompanied by relatively high emissions of trace gases and aerosols (Na, K, As, Zn, In, As, Se, and Au): Many elements (S, Cl, and metals) found in the Erebus plume are common impurities in Antarctic snow. Using a model which assumes a homogeneous distribution of the volcanic gas plume over Antarctica, we suggest that Erebus could be a source of the impurities. We calculate that Erebus could potentially contribute between 4 and 14 ng g(-1) snow of Cl at the south pole, and between 11 and 36 ng g(-1) snow of Cl at Dome C. Excess Cl (Cl in excess of that derived from marine NaCl aerosols) recorded in snow and firn cores from south pole and Dome C could be mainly derived from Erebus. Similarly, our predicted concentrations of Erebus-derived Cu, Zn, Cd, V, As, and Au in Antarctic snow are close to those reported. Trace element and Pb isotope compositions of Erebus aerosols are similar to those collected in remote regions of Antarctica. The volcanic gas plume emitted from Erebus appears to make a significant contribution to the Antarctic atmosphere and can be detected in the snow deposited over a wide area of the continent.