Volcanic outgassing of sulphur and metals
|Dates:||30 October 2019|
|Times:||13:00 - 14:00|
|What is it:||Seminar|
|Organiser:||Department of Earth and Environmental Sciences|
|Who is it for:||University staff, Adults, Alumni, Current University students, General public|
|Speaker:||Prof Marie Edmonds|
Prof Marie Edmonds, University of Cambridge, joins us for a Department of Earth and Environmental Sciences seminar. Abstract below.
It is well known that volcanic eruptions produce sulphur dioxide gases, which may lead to effects on atmospheric chemistry and the radiative budget of the atmosphere. High temperature magmatic gases also contain high concentrations of volatile metals and metalloids, emitted from active volcanoes as gases which may condense to form aerosol particles. Fluxes of volatile metals and metalloids (e.g. Cu, Zn, Pb, As, Se) from individual volcanoes as gases may exceed the industrial flux from entire countries. The abundance of chalcophile and other volatile metals and metalloids in magmas and their associated aqueous fluids is of interest not only for understanding the environmental impact of plumes, but also for understanding the delivery of these elements into upper crustal magma reservoirs, the formation of ore deposits and on a larger scale, the cycling of volatile metals between the interior and surface of Earth through plate tectonics. Volcanic plumes in different tectonic settings contain distinct volatile metal/metalloid assemblages. The pathways of these elements and sulphur are intimately linked from mantle to atmosphere. Sulphide in the mantle retains chalcophile elements during melting. During ascent of magmas to the surface, more than one stage of sulphide saturation may occur. Upon saturation of the magma with an exsolved volatile phase, volatile metals and metalloids partition into it, with a strong dependence on the salinity of the exsolved phase. Degassing of magma at low pressures may cause sulphide-undersaturation and consequent sulphide resorption, which may enhance the outgassing flux of both sulphur and other volatile metals into the atmosphere.
Prof Marie Edmonds
Organisation: University of Cambridge
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