The Active Period of the Core Dynamo of Mars

Details The Active Period of the Core Dynamo of Mars The Active Period of the Core Dynamo of Mars

Dec 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003agufm.p31a..02a&link_type=abstract

American Geophysical Union, Fall Meeting 2003, abstract #P31A-02

Physics

1517 Magnetic Anomaly Modeling, 5440 Magnetic Fields And Magnetism, 5475 Tectonics (8149), 5499 General Or Miscellaneous, 6225 Mars

Scientific paper

The tremendous amount of magnetic field data acquired during the mapping phase of Mars Global Surveyor (MGS) provides a unique opportunity to derive a more accurate magnetic anomaly map of Mars. A most reliable anomaly map is constructed on a global scale through covariance analysis of the spherical harmonic models derived using data from different periods of the mapping phase. I also constructed most reliable magnetic anomaly maps on regional scales, using the covariance analysis in the Fourier domain. Many weak magnetic anomalies are newly detected over the northern lowlands, which are likely relicts of stronger anomalies that have been partially demagnetized by the lowlands formation process and the subsequent low-temperature hydration. The north-south dichotomy of the magnetic anomalies may not have been as drastic before the formation of the lowlands. The lack of distinct magnetic anomalies associated with the entire Valles Marineris, the dike swarms, and the shield volcanoes, as also confirmed by the science phase and aerobreaking phase MGS data, suggests that the upper at least ~5 km of the crust in Tharsis bulge is not significantly magnetized. Rifting a magnetized layer of ~5km thickness, with a magnetization similar to that of the mid-ocean ridge basalt (MORB), on the scale of Valles Marineris would have produced an appreciable magnetic anomaly that could have been detected by MGS. A dike cutting the magnetized layer will create a magnetic anomaly. Although the magnetic anomaly of a single dike decays fast with elevation and cannot be detected by MGS, the collective magnetic field of a wide dike swarm can produce a detectable field. Also, the magnetized layer would have been thermally demagnetized by the over lapping shield volcanoes and could have given rise to detectable magnetic anomalies at MGS altitudes. The upper crust of Tharsis bulge is basaltic and expected to have appreciable magnetic minerals, and the bulge has always been a highland where low-temperature hydration may not have been appreciable. If so, then the core dynamo ceased, or considerably reduced in intensity, before the formation of the upper crust in Tharsis bulge.

Affiliated with

Also associated with

No associations

Rating

The Active Period of the Core Dynamo of Mars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The Active Period of the Core Dynamo of Mars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Active Period of the Core Dynamo of Mars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1425299