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| Titel |
Melt inclusion study of the most recent basanites from El Hierro and Lanzarote, Canary Islands |
| VerfasserIn |
Alejandra Gómez-Ulla, Olgeir Sigmarsson, Maria Jose Huertas, Eumenio Ancochea |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250103242
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| Publikation (Nr.) |
 EGU/EGU2015-2647.pdf |
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| Zusammenfassung |
| The latest eruptions of both Lanzarote (one of the oldest and easternmost of the Canary Island
archipelago) and El Hierro (the youngest and westernmost) produced basanite lavas. Major,
volatile and trace element concentrations of melt inclusion (MI) hosted in olivine for both
eruptions have been analysed. The basanites display primitive mantle normalized
trace element spectra suggesting a magma source largely composed of recycled
oceanic crust. In addition, beneath Lanzarote an interaction with a carbonatitic
fluid phase or metasome would explain eccentric Ba/U and other trace element
ratios. Contribution of carbonatitic component would readily account for extremely
volatile-rich (Cl, F, S) MI from Lanzarote (Cl=1577-2500 ppm) whereas the maximum for
El Hierro is 1080 ppm. The submarine character of the 2011-12 eruption off El
Hierro appears to have affected the degassing behavior, whereas estimated sulfur
emission to the atmosphere during the historical Lanzarote eruptions are amongst
the highest observed so far. An estimated magma volume (VDRE) of 0.02 km3
yields atmospheric mass loading of 0.2 Mt SO2 from the 1824 Lanzarote eruption.
Scaling the volume of the 1824 Lanzarote eruption to that of the previous Timanfaya
eruption (1730-6; 5 km3) results in estimated 12 Mt SO2, an atmospheric mass
loading only outnumbered by the historical Laki and Eldgjá eruptions in Iceland. The
significantly greater volatile budget of basanites from Lanzarote compared to El Hierro is
thus controlled by more fertile source composition closer to the African continent. |
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