Upper mantle magma storage and transport under a Canarian shield-volcano, Teno, Tenerife (Spain)

被引:35
|
作者
Longpre, Marc-Antoine [1 ]
Troll, Valentin R.
Hansteen, Thor H. [2 ]
机构
[1] Univ Dublin Trinity Coll, Dept Geol, Coll Green, Dublin 2, Ireland
[2] Leibniz Inst Meereswissenschaft, IFM GEOMAR, D-24148 Kiel, Germany
关键词
D O I
10.1029/2007JB005422
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
We use clinopyroxene-liquid thermobarometry, aided by petrography and mineral major element chemistry, to reconstruct the magma plumbing system of the late Miocene, largely mafic Teno shield-volcano on the island of Tenerife. Outer rims of clinopyroxene and olivine phenocrysts show patterns best explained by decompression-induced crystallization upon rapid ascent of magmas from depth. The last equilibrium crystallization of clinopyroxene occurred in the uppermost mantle, from similar to 20 to 45 km depth. We propose that flexural stresses or, alternatively, thermomechanical contrasts create a magma trap that largely confines magma storage to an interval roughly coinciding with the Moho at similar to 15 km and the base of the long-term elastic lithosphere at similar to 40 km below sea level. Evidence for shallow magma storage is restricted to the occurrence of a thick vitric tuff of trachytic composition emplaced before the Teno shield-volcano suffered large-scale flank collapses. The scenario developed in this study may help shed light on some unresolved issues of magma supply to intraplate oceanic volcanoes characterized by relatively low magma fluxes, such as those of the Canary, Madeira and Cape Verde archipelagoes, as well as Hawaiian volcanoes in their postshield stage. The data presented also support the importance of progressive magmatic underplating in the Canary Islands.
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页数:11
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