Insight into the formation mechanism of the Medusae fossae formation on Mars from magnetic field data

The Medusae Fossae Formation (MFF) is one of the largest unconformable deposits on Mars. The origin of the MFF is unknown, but several formation processes have been proposed, including volcanic, wind, and ice-related mechanisms. An insight into the nature and the origin of the MFF may be ascertained by examining the degree of magnetization carried by the MFF. Here we examine the high-resolution nighttime magnetic field data from the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft over the MFF to ascertain the degree of magnetization carried by the MFF. By showing small modulations in the magnetic field induced by impact craters superposed on the MFF, we demonstrate that the MFF is strongly magnetized close to Apollinaris Mons. Distal to Apollinaris Mons, the MFF displays a relatively lower degree of magnetization. We show that the MFF most likely got magnetized via thermal remanent magnetization, indicating that the MFF near Apollinaris Mons was emplaced as a high-temperature volcanic product. We propose that the decline in remanent magnetization |B| with distance from Apollinaris Mons could be related to lower emplacement temperature. We combine the magnetic field constraints with previous observations of the MFF and propose that the MFF was likely emplaced as a volcanic deposit.

Automated summary

The Medusae Fossae Formation (MFF) on Mars is a large unconformable deposit with an unknown origin. Through examining the degree of magnetization carried by the MFF, insights into its nature and origin can be obtained. Using high-resolution nighttime magnetic field data from the MAVEN spacecraft, it has been shown that the MFF is strongly magnetized near Apollinaris Mons, likely indicating a high-temperature volcanic origin. The decline in remanent magnetization with distance from Apollinaris Mons suggests lower emplacement temperature and supports the hypothesis that the MFF is a volcanic deposit.