A polar magnetic paleopole associated with Apollinaris Patera, Mars

Abstract

A Martian paleomagnetic pole is calculated from a magnetic anomaly associated with the late Noachian age (and older) volcano Apollinaris Patera. This isolated volcano, located near the crustal dichotomy boundary at the Martian equator, has a correlative gravity anomaly, and was likely active for more than 10 7 years. It is one of the only volcanoes on Mars known to have a substantial magnetic anomaly associated with it, and one of the only examples of correlative magnetic and gravity sources. Magnetic directions calculated using either low- or high-altitude data, and single or multiple equivalent source dipoles, are nearly horizontal and southward directed. Assuming a single dipolar source magnetization, the preferred paleopole is at 65 ∘ S , 59 ∘ E . Assuming a larger magnetized area leads to a cluster of paleopoles near 88 ∘ S , 99 ∘ E . This paleopole is very close to the current rotation pole, and very different from previously calculated paleopoles. Our preferred interpretation is that the Apollinaris Patera magnetization was acquired near the end of the life of the Martian dynamo, and that subsequent polar wander was minimal.