Journal Highlights

Evaluating an impact origin for Mercury’s high-magnesium region

Editors’ Highlight—The MESSENGER spacecraft that orbited Mercury from 2011-2015 measured the elemental abundances of many major elements in order to understand the bulk composition of the planet and the processes that shaped its surface. One of the more surprising discoveries in the planet’s surface composition is a nearly 3000-km diameter region with a significantly elevated abundance of magnesium. This study tests the hypothesis that this high-Mg region is the result of a large impact that excavated the mantle. The results indicate that a large impact would not result in a recognizable signature in surface Mg composition. Thus, the authors ascribe the origin of this area to high-temperature volcanism, which would retain an elevated Mg signature.