A Deep-Mantle Garnet Might Hold the Secret to Ancient Martian Magma

A history of a planet’s volcanic activity is contained in its rocks. And Mars’ rocks - or at least many of the meteorites that have made the journey from it to Earth - were telling a contradictory story. They appeared to be highly oxidized, but our understanding of the internal volcanic forces on Mars meant that they should have been formed in a reducing environment - the exact opposite of what the chemical makeup of the rocks themselves indicate. Now, a new paper published in the Journal of Geophysical Research: Solid Earth from planetary scientists Hideharu Kuwahara and Ryoichi Nakada of Ehime University provides an answer as to why - and it involves a gemstone.