Constraints on the Martian Core Dynamo: The Magnetic Signature of Apollinaris Patera

Most plausibly, the magnetic field of Mars results from magnetic rocks which obtained their magnetization in the presence of a core dynamo. However, it is disputed how long this core dynamo was active: The magnetic signatures of large impact craters and of some volcanoes are consistent with a shutdown in the Noachian period [1-2], whereas the study of paleopoles and the magnetic imprint of some other volcanoes suggest an active core dynamo in the Hesperian [3-5]. The strongest argument for the latter interpretation is based on the magnetic signature of the volcano Apollinaris Patera. Here, we challenge this interpretation by investigating the magnetic field at lower altitudes