Volcanic ash leaching as a means of tracing the environmental impact of the 2011 Grímsvötn eruption, Iceland

The Grímsvötn volcanic eruption, from 21 to 28 May, 2011, was the largest eruption of the Grímsvötn Volcanic System since 1873, with a Volcanic Explosivity Index (VEI) of magnitude 4. The main geochemical features of the potential environmental impact of the volcanic ash-water interaction were deter...

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Detalles Bibliográficos
Autores: Cabré, J., Aulinas, M., Rejas, Marta, Fernandez-Turiel, J. L.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2016
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/130938
Acceso en línea:http://hdl.handle.net/10261/130938
Access Level:acceso abierto
Palabra clave:Volcanic ash
Water leaching
Geochemical flux
Grímsvötn
Descripción
Sumario:The Grímsvötn volcanic eruption, from 21 to 28 May, 2011, was the largest eruption of the Grímsvötn Volcanic System since 1873, with a Volcanic Explosivity Index (VEI) of magnitude 4. The main geochemical features of the potential environmental impact of the volcanic ash-water interaction were determined using two different leaching methods as proxies (batch and vertical flow-through column experiments). Ash consists of glass with minor amounts of plagioclase, clinopyroxene, diopside, olivine and iron sulphide; this latter mineral phase is very rare in juvenile ash. Ash grain morphology and size reflect the intense interaction of magma and water during eruption. Batch and column leaching tests in deionised water indicate that Na, K, Ca, Mg, Si, Cl, S and F had the highest potential geochemical fluxes to the environment. Release of various elements from volcanic ash took place immediately through dissolution of soluble salts from the ash surface. Element solubilities of Grímsvötn ash regarding bulk ash composition were <1 %. Combining the element solubilities and the total estimated mass of tephra (7.29 × 1014 g), the total inputs of environmentally important elements were estimated to be 8.91 × 109 g Ca, 7.02 × 109 g S, 1.10 × 109 g Cl, 9.91 × 108 g Mg, 9.91 × 108 g Fe and 1.45 × 108 g P The potential environmental problems were mainly associated with the release of F (5.19 × 109 g)