Rapid transcrustal magma movement under Iceland ...

• Main Authors: Mutch, Euan JF, Maclennan, John, Shorttle, Oliver, Edmonds, Marie, Rudge, John F
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer-Nature 2019
• Subjects: 37 Earth Sciences; 3703 Geochemistry; 3705 Geology; 3706 Geophysics; Borgarhraun; Iceland
• Online Access: https://dx.doi.org/10.17863/cam.41468; https://www.repository.cam.ac.uk/handle/1810/294367

Magma supply from the lower crust is often proposed as a trigger mechanism for volcanic eruptions. The timescales over which magma can be transported from the deepest parts of volcanic systems are, however, poorly constrained. This uncertainty poses problems for the construction of physical models and for assessment of volcanic hazards. Here, we combined geothermobarometry with Bayesian inversion diffusion chronometry on primitive olivine crystals from the Borgarhraun eruption, northern Iceland. We find that magma took about 10 days to ascend from near-Moho storage at 24 km depth before its eruption, and therefore present timescales for transcrustal magma transport on the global spreading ridge system. Our results reveal a rapid connection between the lower and upper crust with melt transport rates of 0.02 to 0.1 m s−1, which are consistent with the propagation rates observed in seismic swarms in the Icelandic lower crust. Monitoring of such events using surface CO2 fluxes may provide one of the earliest ...