title: Experimental evidence for the source of excess sulfur in explosive volcanic eruptions
abstract: The amounts of sulfur released in explosive volcanic eruptions are often orders of magnitude larger than those expected to result from the degassing of the erupted SiO2-rich magma. Experimentally measured fluid/melt partition coefficients of sulfur ranged from 47 under oxidizing conditions (where SO2 is the dominant sulfur species in the fluid) to 468 under reducing conditions (where H2S dominates). Therefore, a few weight percent of hydrous fluid accumulated in the top of a magma chamber may extract most of the sulfur out of the entire magma reservoir and generate sulfur excesses upon eruption.
authors.affiliation: Bayerisches Geoinstitut, Universitat Bayreuth, 95440 Bayreuth, Germany.
authors.initials: H
authors.lastname: Keppler