Final Report Summary - ELECTROLITH (Electrical Petrology: tracking mantle melting and volatiles cycling using electrical conductivity)
Magmatism is an essential process on planet Earth that is mostly taking place at depth within the planet interior while volcanism constitutes a spectacular but very minor part of it. The dominant magmatic processes remain deep, inaccessible, enigmatic and can mainly be decrypted form petrological (ie. the mineralogy of rocks) and geochemical analyses of rocks exhumed to the surface by complex and slow geological processes. Can we relate the real-time observations provided by the geophysical probing of the Earth's interior to the long-lasting magmatic processes decrypted by geochemical surveys? This question requires the confrontations of temporal, spatial and physical issues converting magmatic processes into the electrical and seismic properties of the planet interior as recorded by geophysics. Electrolith tackles this conversion issue by deploying a methodology that we call Electrical Petrology: A combination of laboratory measurements and sophisticated models allows us to illuminate deep magmatic processes by reconciling geophysical observations and petrological models. Electrolith has shown that the so called magmatic volatiles, that is H2O and CO2 in the Earth’s interior, are the key to decipher the geophysical records of deep magma. Geophysics mostly see deep CO2 and H2O-rich magma being stagnant at different level within the crust and the mantle. These stagnant melts are not dormant as they can be remobilized and they trigger mechanical discontinuities with far-reaching implications on the planet geodynamics.