Contribution of volcanic ashes to the regional geochemical balance: The 2008 eruption of Chaitén volcano, Southern Chile
The environmental geochemical behaviour of the rhyolitic ashes from the 2008 eruption of Chaitén volcano, Southern Chile, has been studied. After the bulk characterisation, the potential contribution to the regional geochemical fluxes was examined using: i) single batch leaching tests to provide a r...
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| Autores principales: | , |
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2012
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00489697_v425_n_p75_Ruggieri http://hdl.handle.net/20.500.12110/paper_00489697_v425_n_p75_Ruggieri |
| Aporte de: |
| Sumario: | The environmental geochemical behaviour of the rhyolitic ashes from the 2008 eruption of Chaitén volcano, Southern Chile, has been studied. After the bulk characterisation, the potential contribution to the regional geochemical fluxes was examined using: i) single batch leaching tests to provide a rapid screening of the implied major and trace elements; and ii) column experiments to evaluate the temporal mobility of leached elements. The environmental concerns of these ashes are related to the fine grained component present in each sample (independent of distance from the source), in particular the presence of cristobalite, and the geochemical hazards posed by ash-water interaction. Leaching experiments show the fast dissolution of surface salts and aerosols, which dominate over glass dissolution during the first steps of the ash-water interaction. Chaitén ashes could transfer to the environment more than 1×10 10g or 10,000metric tonnes (mt) of Cl, S, Ca, Na, Si, and K; between 1000 and 10,000mt of F, Mg, and Al; between 100 and 1000mt of As, Pb, P, Fe, Sr, Zn, Mn, and Br; between 10 and 100mt of Ba, Li, Ti, Ni, Nb, Cu, Rb, Zr, V, Mo, Co, and Sc; and less than 10mt of Cr, Sb, Ce, Ga, Cs, and Y. These results show the fertilising potential of the ashes (e.g., providing Ca and Fe) but also the input of potentially toxic trace elements (e.g., F and As) in the regional geochemical mass balance. The Chaitén results evidence lower potentials for poisoning and fertilising than low silica ashes due to the lower contents released of practically all elements. © 2012 Elsevier B.V. |
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