Subduction zones are characterized by significant geological activities including arc volcanism and earthquakes. At subduction zone settings, hydrated crusts are subducted into the mantle. This releases fluids and rehydrates mantle wedges. It also provides an additional source of aqueous fluid above the slab causing melting and eventually arc volcanism. Often, mantle wedge regions are characterized by anomalously high electrical conductivity signals. Geophysicists have been invoking aqueous fluids with enhanced salinity to explain such observations.
In a recent article published in Science Advance, Mainak Mookherjee and his colleagues at Laboratory Magmas et Volcans, France, propose an alternate mechanism. Upon dehydration, chlorite transforms to a mixture of olvine, pyrope, and magnetite. The experimental study demonstrates that highly conductive magnetite forms an interconnected network during the dehydration of natural chlorite and explains the anomalously high electrical conductivity.
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