Eruption at Sundhnúksgígar, November 2024 – preliminary petrographic and geochemical results
Quenched lava samples were collected on the 21st November from nearby Grindavíkurvegur. The chemical composition of the samples was analysed using the electron microprobe at the Institute of Earth Sciences, University of Iceland. The initial results show that the lavas are very similar to those erupted in the last two events at Sundhnúksgígar (May-June 2024 and August 2024), with the MgO content of the volcanic glass in the range 5-6 wt% and K2O/TiO2 between 0.13 - 0.14. This composition is also very similar to the lavas erupted during the medieval Reykjanes fires.
These compositions are consistent with magma accumulation at a similar depth and temperature (Fig. 1A) to the previous eruptions at Sundhnúksgígar. The lack of variations in K2O/TiO2 over the past six months (Fig. 1B) indicates little change in the magma accumulation zone with time, meaning that the current cycle of volcanism will likely continue in a similar way while Svartsengi continues to be supplied with magma from deeper sources.
