Timing, Distribution and Petrological Evolution of the Teide-Pico Viejo Volcanic Complex

Several cycles of initially mafic to progressively felsic activity have given rise to large volume felsic deposits on Tenerife that serve as prime examples of pronounced magmatic differentiation in an ocean island setting. The Teide–Pico Viejo succession is the most recent of these cycles to show a systematic evolution from initially basanitic to phonolitic eruptions. Basanite lava flows bear olivine, pyroxene and occasionally plagioclase, while phonolites mainly display alkali feldspar with subordinate pyroxene, amphibole, biotite and oxides. Three groups of eruptives can be discerned based on their trace element composition: (1) Mafic lavas that show typical OIB signatures, (2) Transitional lavas, which are enriched in incompatible trace elements but may be depleted in Ba and Sr and (3) Phonolites, which are more enriched in incompatible trace elements, but show the strongest negative Ba and Sr anomalies. Linking the spatio-chronological distribution of eruptions with these compositional groups shows a progressive migration of mafic activity from the outskirts of the rift zones towards the central complex over the last 30 ka. The arrival of mafic activity at the central complex coincided with the onset of more evolved eruptions at Teide, thought to be triggered by mafic underplating. The distribution of mafic activity at the surface may thus be related to the volume of mafic underplating beneath the volcanic edifice at a given time.