期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2008
卷号：3
出版社：IOP Publishing
摘要：We have performed phase equilibrium experiments to determine the pre-eruptive
conditions of the largest phonolitic caldera-forming eruption (~20 km3 of DRE)
that occurred on Tenerife (Canary Islands). The Abrigo ignimbrite was erupted
during the last caldera-forming episode (ca. 190 ka), from the Cañadas caldera.
Comparison of the natural and experimental phase proportions and compositions
indicates that the phonolite at the roof of the Abrigo magma reservoir was at
130 ± 50 MPa (corresponding to ca. 4 - 5 km below the surface), 825 ± 25 oC,
with 3 ± 1 wt% dissolved H2O and fO2 at the Ni-NiO buffer ? 1 log unit. This
shows that the magma that produced the largest ignimbrite on Tenerife was stored
at relatively shallow depths but was water-undersaturated, and its eruption was
probably triggered by input of fresh mafic magma.
