Abstract
Magnetotellurics (MT) is a passive electromagnetic geophysical method that can image the Earth's electrical conductivity to asthenospheric
depths. One of the main factors controlling the electrical conductivity of the lithospheric mantle is the hydrogen content of nominally anhydrous minerals such as olivine and pyroxene. Hydrogen content is affected by important geological processes such as partial melting and metasomatism and also has a strong influence on mantle rheology. In this seminar, I will introduce the MT method and show how MT can be used to determine the hydrogen content of the mantle in situ. I will discuss the implications for understanding lithospheric evolution and rheology, with a focus on examples from East Africa and central Australia.