geophysics

Lower-mantle iron heterogeneity constrained by the electrical conductivity of Al-bearing bridgmanite

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Map showing global iron content distribution in the lower mantle at 1225 kilometres depth with LLSVP boundaries outlined.

Scientists measured how well iron-bearing bridgmanite, the main mineral in Earth’s lower mantle, conducts electricity under high pressure and temperature conditions. They found conductivity rises sharply with iron content but barely changes with temperature, allowing iron variations to be mapped directly from global conductivity models derived from geomagnetic data. The results suggest iron-rich material within … Read more…

5.8 magnitude Mansfield earthquake reflects compressive intraplate stress reactivating deep faults

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Forces acting along the edges of tectonic plates, particularly compressive forces caused by plate convergence and orogeny, propagate into the interior of plates and cause deformation within continents. Forces acting on the edges of plates include compressive forces due to plate collisions and mountain building, so-called “ridge push” forces caused by the excess gravitational potential … Read more…