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Composición de la caída de cenizas del monte St. Helens en el área de Moscú-Pullman el 18 de mayo de 1980
Science (New York, N.Y.)
|September 5, 1980
Resumen
La caída de cenizas volcánicas del Monte St. Helens el 18 de mayo de 1980, comprendió dos tipos distintos de cenizas. Los análisis mineralógicos y químicos revelaron diferencias significativas entre las primeras cenizas oscuras y las posteriores cenizas pálidas.
Área de la Ciencia:
- La geoquímica es la geoquímica.
- La mineralogía es la Mineralogía.
- Volcanología Volcanología.
Sus antecedentes:
- La erupción de 1980 del Monte St. Helens produjo una extensa caída de cenizas.
- Comprender la composición de la ceniza volcánica es crucial para evaluar su impacto.
Objetivo del estudio:
- Para llevar a cabo análisis minerales y químicos detallados de la caída de ceniza de la erupción del 18 de mayo de 1980.
- Para diferenciar y caracterizar los distintos tipos de cenizas depositadas.
Principales métodos:
- Análisis mineralógico de muestras de cenizas.
- Análisis químico de las fracciones de ceniza y componentes de vidrio.
- Identificación de las fases minerales y composición elemental.
Principales resultados:
- Se identificaron dos tipos distintos de ceniza: una ceniza oscura temprana y una ceniza pálida posterior.
- Las cenizas oscuras contenían plagioclasa, fragmentos líticos, magnetita, hornblenda y ortopirroxeno.
- La ceniza pálida era predominantemente de vidrio (80%) con plagioclasa como la fase cristalina principal; el cuarzo y el feldespato de potasio eran raros.
Conclusiones:
- Los datos mineralógicos y químicos confirman la presencia de dos tipos distintos de cenizas de la erupción del Monte Santa Helena.
- Los análisis ponen de relieve diferencias significativas en la composición entre los depósitos de ceniza tempranos y posteriores.
- Ambos tipos de cenizas exhibieron homogeneidad química interna dentro de sus respectivas fracciones.
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