Utilising 3-D magnetotelluric models of southern African mantle to constrain hydrogen content and compositional variations.

Abstract

Summary The magnetotelluric method is the most sensitive geophysical tool in detecting the hydration state of the mantle. Therefore, improved interpretations of electrical conductivity distribution within the Earth is a key measure that has to be taken in order to have a better grasp on lithopsheric-scale geodynamic concepts and the nature of mineralising agents. Progress towards this goal requires detailed comparisons between MT models and xenolith data in order to understand the controls on mantle electrical conductivity. In this study, new magnetotelluric models from southern Africa were utilised to constrain the composition and hydrogen content by comparing forward models based on the experimental studies made on mantle minerals at high P-T conditions. Many relations between the experimental parameters and information from xenolith data were tested to improve the capabilities of magnetotellurics as an exploration tool in the lithospheric mantle of cratons.