Determining crustal melt and water contents from geophysics and experimental work to characterize a long dormant volcano: Ciomadul (Romania)
Abstract
Geophysical surveys provide live images of deep regions of the Earth. They may reveal anomalies caused by the presence of fluids (melt, water…) such as beneath volcanic provinces where magma can be stored for 100's ka in the crust. Although most active volcanoes display eruption frequencies lower than 1000 years, a class of volcanic systems has extremely long repose-time, exceeding 10 ka. Such long dormant volcanoes pose a particular threat for society because little is known about the way they stir back to life. Reawakening primarily depends on the nature of the subvolcanic magma reservoir, particularly on the presence of melt.
Here, we combine petrologic, geophysical, experimental and thermal modeling data to constrain the current condition of magma storage beneath Ciomadul, a seemingly inactive volcano in eastern-central Europe that erupted last time 32 ka ago. Through a new methodology linking predictive thermomechanical models and measured electrical conductivity constraints at crustal scale, we show that the subvolcanic storage could still hold several 10s km3 water-rich silicic melt, representing up to 20-40 % of the upper crustal magma body. The presence of such shallow melt-bearing mush zone implies that magma rejuvenation is still possible upon recharge on a relatively short timescale. Hence, Ciomadul, as many other seemingly inactive volcanoes, is likely capable of erupting in the future.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMDI42A..05L
- Keywords:
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- 3914 Electrical properties;
- MINERAL PHYSICSDE: 3619 Magma genesis and partial melting;
- MINERALOGY AND PETROLOGYDE: 5724 Interiors;
- PLANETARY SCIENCES: FLUID PLANETSDE: 8147 Planetary interiors;
- TECTONOPHYSICS