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Kathy Whaler is a geophysicist from the University of Edinburgh, Scotland, spending 3 months at Goddard as part of a sabbatical leave. She and Mike Purucker think they have found on Mars a magnetic signature like that associated with a plate tectonic structure on Earth where continental rifts intersect over mantle plumes. |
 Modeled declination (top) and inclination (bottom) |
Whaler and Purucker produced a new model of crustal magnetization derived from the vertical field magnetic data measured by Mars Global Surveyor. They solve for magnetization directions, and so can produce maps of both the declination and inclination, as in the Figure to the left. |
Detail of the Tyrrhena area. Note the 3-arm pattern in anomaly amplitude. |
The clearest “triple junction-like” feature is labeled “T” for Tyrrhena Patera, an old volcanic center located northeast of the Hellas basin. The inclination reverses completely from +90 to -90 degrees along the “arms” of the proposed triple junction. If really a triple junction, the magnetic field must have reversed at least once to produce the pattern seen. |
Declination and Inclination map
Walter Kiefer of the Lunar and Planetary Institute and a former RRA in the Geodynamics Branch, presented a paper at the March ’03 Lunar and Planetary Science Conference suggesting the gravity data over Tyrrhena may indicate an extinct magma chamber below the old volcanic center. His model infers a size that is similar to the central magnetic anomaly feature described by Whaler and Purucker.
Contact: Mike Purucker, GSFC, Code 921 (purucker@geomag.gsfc.nasa.gov)
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Responsible NASA official: Dr. Herbert Frey