Investigating serpentinization in the Samail ophiolite using broad-band magnetotelluric survey

Serpentinization reactions in ophiolites naturally generate H2 as well as the excess of aqueous cations (e.g. Mg2+, Ca2+) necessary for permanently binding CO2 into carbonate minerals. For either H2 production or CO2 sequestration to be economically viable either these natural reaction rates must be drastically increased or an existing reservoir of accumulated H2 or evolved hyperalkaline fluid must be located. The magnetotelluric (MT) method, being sensitive to zones of increased electrical conductivity, can provide information for modelling the subsurface H2-generating serpentinization system and for locating hyperalkaline fluid reservoirs as well as monitoring the sequestration process. To explore this potential we have conducted a 2D MT survey of part of the Samail ophiolite. MT data is collected at nine sounding locations along an approximately 20 km long east–west oriented profile across the northwestern edge of the ophiolite. We present results of MT inversion constrained by seismic image and surface and subsurface geological data. Interpretation of the resistivity model provides a revised structural model of the Samail thrust and the sub-surface serpentinization system.