although temperature measurements of io's volcanoes settled the sulfur-versus-silicates debate that persisted between the "voyager" and "galileo" missions at jupiter, sulfur and sulfur dioxide still play a significant role in the phenomena observed on io. both materials have been detected in the plumes generated at io's volcanoes, with sulfur being a primary constituent of pele-type plumes. bright flows have been identified on io, at tsũi goab fluctus, emakong patera, and balder patera for example, that are suggestive of effusive sulfur or sulfur dioxide volcanism.