Seminar: Professor Anthony Williams-Jones, Howard Street Robinson Lecturer. Title: Metals, Vapours, and Volcanoes

Until recently, conventional wisdom has held that the main agent of metal transport in hydrothermal systems is an aqueous liquid. However, there is increasing evidence from volcanic vapours, geothermal systems (continental and submarine), vapour-rich fluid inclusions, and experimental studies that the vapour may be an important and even dominant ore fluid in some hydrothermal systems, notably those that form porphyry and epithermal deposits. Here we present evidence for the transport of metals by vapor (an aqueous fluid of any composition with a density lower than its critical density), clarify some of the thermodynamic controls that may make such transport possible, and propose a model for the formation of porphyry and epithermal deposits that involves precipitation of the ores from vapour.

Speaker Bio: GAC Howard Street Robinson Lecture Tour_2025-2026_Dr. Williams-Jones.pdf