The Holocene volcanism of El Hierro, Canary Islands

El Hierro is, together with La Palma, the youngest island of the Canarian Archipelago. Both islands are in the shield stage of their volcanic growth, which implies a high volcanic activity during the Holocene period. The submarine eruption occurred in October 2011 in the SSE rift of El Hierro evidenced the active volcanic character of the island. Even so, despite the numerous scientific works published following the submarine eruption (most of them centered to understand such volcanic event), there is still a lack of precise knowledge about the Holocene subaerial volcanism of this island. The LAJIAL Project focuses on solving this knowledge gap.

The Holocene subaerial volcanism of El Hierro generates fields of monogenetic volcanoes linked to the three systems of rifts present on the island. Its eruptive mechanisms are typically Strombolian although there are also phreato-Strombolian events. The most recent eruptions frequently form lava on coastal platforms, which are considered after the last glacial maximum (approx. 20 ka BP). The most developed coastal platforms in El Hierro are at the ends of the rifts and in the interior of the El Golfo depression. This geomorphological criterion shows that more than thirty subaerial eruptions have taken place in El Hierro since approx. 20 ka BP. In addition, there are many apparently recent volcanic edifices far from the coast.

The research of the most recent volcanism of the island, the last 11,700 years of the Holocene, covers a long enough period whereas it is close to the present day. Thus, this period is the best to model the eruptive processes that will allow us to evaluate the future scenarios of the eruptive dynamics in El Hierro. The Project LAJIAL combines methodologies of geological mapping, geomorphology, GIS, chronostratigraphy, paleomagnetism, petrology and geochemistry to solve the Holocene eruptive recurrence rate in El Hierro, and to constrain the rift model of intraplate ocean volcanic islands.

Financial support was provided by the Project LAJIAL (ref. PGC2018-101027-B-I00, MCIU/AEI/FEDER, EU). This study was carried out in the framework of the Research Consolidated Groups GEOVOL (Canary Islands Government, ULPGC) and GEOPAM (Generalitat de Catalunya, 2017 SGR 1494).