Nuevas edades K-Ar de las rocas volcánicas de la isla de Tenerife

Abstract

Six new isotopic age determinations were established in volcanic rocks of Tenerife. These data belong to different units of the main volcanic edifices and the results allow us to get a more accurate knowledge of the eruptive history of the island. One of these ages corresponds to a trachyandesitic flow of the Upper Unit of the Anaga Old Edifice (Old Basaltic Series) and the result, 3,38 ±0,19 Ma matches with the age interval established by previous authors for this unit (3,70 - 3,28 Ma). Three ages belong to units of the Cañadas Edifice and the results are 1,59 ± 0,19 Ma, 2,94 ± 0,15 Ma and 4,0 ± 0,2 Ma. This shows that the felsic volcanic activity started in the very early stages of the Cañadas Edifice evolution and it shows also that there are a partial overlap with the youngest episodes of the Old Tenerife Edifices. The age determination on a phonolitic plug that intrudes on basaltic flows of the Dorsal Edifice gives a result of 1,16 ± 0,09 Ma. The last age data of this work belongs to a mafic phonolite flow of a peripherial volcano (Taco Mountain). The result, 0,55 ± 0,06 Ma reinforces the evidence of felsic-intermediate volcanic activity in several peripherial volcanoes contemporary with the Cañadas Edifice lifespan.