An updated overview of the geochemistry of Teide-Pico Viejo volcanic complex (Tenerife island, Spain).

Whole rock and single mineral geochemical data in volcanic rocks record a wide variety of volcanic processes, such as magma storage conditions and evolution, pre-eruptive processes, transport to the surface, etc. All this information is crucial for knowing the functioning of a volcano plumbing system and trying to anticipate volcanic eruptions, especially in central volcanoes. The active Teide-Pico Viejo (T-PV) volcanic complex on the island of Tenerife (Canary Islands) combines effusive and explosive activity with long recurrence periods. This makes it necessary to carefully study the volcanic stratigraphy in order to understand how the volcano may erupt in the future and which processes may lead to eruption. Tenerife island is a very populated and touristic area, so hazard assessment at its main volcanic complex is mandatory. However, petrological and geochemical information regarding the T-PV stratovolcanoes is very dispersed and out-of-date, with analyses of individual units made over the course of several decades, using different techniques and laboratories, and sometimes difficult to relate to a systematic stratigraphy. It is therefore necessary to create a complete database that will allow further progress in this field and will avoid future repetition of analyses for which quality data are already available.

Here, we present the preliminary results from a complete geochemical database of the different T-PV volcanic units. From the available literature (more than 30 references so far), 971 whole rock, 217 residual glass and 8474 mineral chemistry analysis have been included. The inputs have been classified depending on their stratigraphic unit whenever possible. We also provide new petrological data from 79 rock samples from all outcropping units at T-PV, paying particular attention to the stratigraphy. These analyses will provide an update of the geochemical data for one of the most important active volcanic systems in Europe, allowing a better comparison between units and greater accuracy (especially in the case of trace elements) by obtaining data for a wide variety of elements, all performed in the same laboratory (Peter Hooper GeoAnalytical Lab, Washington State University). Also, a new and complete set of mineral analyses is presented, with special attention to mineral zoning, that will allow us to better understand the different magmatic processes occurred in that volcanic system.

Based on the volcanic stratigraphy and this new collection of geochemical data, this project will radiometrically date both rocks and mineral separate (feldspars), whenever possible, in order to calculate more accurate recurrence intervals and the timescales of magmatic evolution on Tenerife and will also examine still-debated aspects of the magmatic evolution of T-PV stratovolcanoes, such as the origin of phonolites or the existence or not of a “Daly Gap” in magma compositions, within a temporal context.

OD was supported by an FPU grant (FPU18/02572) and a complementary mobility grant (EST19/00297) from the Ministry of Universities of Spain. JM and AG were funded by the European Commission Grants EVE (ref: DG ECHO H2020 826292) and EUROVOLC (ref: H2020 731070).