Datos preliminares de los primeros fragmentos flotantes de material volcánico emitidos en la erupción submarina de octubre de 2011 al sur de la isla de El Hierro (Islas Canarias)
- J.A. Rodríguez-Losada 1
- A. Eff-Darwich 1
- J. Martínez-Frías 2
- L.E. Hernández-Gutiérrez 1
- R. Viñas 1
- N. Pérez 3
- P. Hernández 3
- G. Melián 3
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1
Universidad de La Laguna
info
- 2 Centro de Astrobiología (CSIC/INTA)
- 3 Instituto Volcanológico de Canarias (INVOLCAN).
ISSN: 1576-5172
Datum der Publikation: 2012
Titel der Ausgabe: VIII Congreso Geológico de España, Oviedo, 17-19 de julio, 2012.
Nummer: 13
Seiten: 906-909
Art: Artikel
Andere Publikationen in: Geotemas (Madrid)
Zusammenfassung
This paper describes the preliminary features of the floating fragments of volcanic material emitted in the initial stages of the submarine eruption focused south of La Restinga village at El Hierro Island. They appeared dispersed in an area located 3 to 5 km south of the coastline of the town. The fragments are characterized by a major internal part of white to greyish colors and with a rhyolitictrachytic composition, covered with a minor thin black crust (ranging from 0,5 to 1,5 cm thick) of basanitic composition invading the white inner part as convolutions. Both parts appear separated by net contacts, setting up a process of "mingling". Noteworthy is the high silica content (up to 71% by weight) and the high porosity of the inner material, with a true density of 2.47 g/cm3 , bulk density of 0.3-0.4 g/cm3 and a total pore surface up to 41 m2 /g . This part exhibits the highest U concentration, with a U/Th relationship equal to or greater than 3, values never seen before in volcanic rocks of the Canary Islands. Today, it remains an open debate on the juvenile or not origin of these white, highly siliceous and highly porous inner parts.