Mathematics – Logic
Scientific paper
May 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agusm.p31a..04r&link_type=abstract
American Geophysical Union, Spring Meeting 2004, abstract #P31A-04
Mathematics
Logic
1517 Magnetic Anomaly Modeling, 5417 Gravitational Fields (1227), 5440 Magnetic Fields And Magnetism, 6225 Mars
Scientific paper
The magnetic field of Mars reflects strong crustal magnetism resulting from an ancient internal field. The crustal anomaly pattern parallels the geologic dichotomy in that most of the anomalies detected by the Mars Global Surveyor are located within the persumably older southern highlands while the northern lowlands has weak or no magnetic signature at satellite atltiudes. We have analyzed a section of the dichotomy boundary whose geology has been studied extensively in order to examine the implications of correlations between gravity and magnetic anomalies for the regional distribution of magnetic sources. The study area contains some of the strongest magnetic anomalies observed outside the area of high-amplitude anomalies found within the Terrae Cimmeria and Sirenum sector of the southern highlands. Several strong magnetic and gravity anomalies in the area of the Ismenius quadrangle are associated with a mapped normal fault, but the magnetic and gravity peaks and troughs are out of phase. The isostatic gravity anomalies indicate higher density bodies flanking the mapped normal fault. If we assume common sources of both the gravity and magnetic anomalies, and a coherent direction of magnetization within a spatially variable source layer, we acheive the best fit to both the gravity and magnetic fields using a low inclination for the magnetization direction (~30 degrees), in general agreement with published paleopole estimates for Mars. This solution requires a continuous magnetic source layer extending north beneath the plains to avoid a large edge effect anomaly; this layer produces near-zero field away from the fault. An alternate model assumes that the gravity anomalies correspond to areas of demagnetization of a preexisting continuous magnetic source layer. This model fits best for an inclination near -45 degrees and does not require a source layer in the northern plains. Candidate geologic processes that could have produced such source distributions in the study area include extension and volcanic intrusion focused near the dichotomy boundary, and hydrothermal alteration which created, destroyed, or reduced the magnetism. The product of layer thickness and magnetic intensity implied by these models is roughly 5-10 times less than inferred in the highly magnetized region of the southern highlands, indicating significantly different genesis or evolution of the crust occurred in that region as compared to the rest of Mars.
Dimitriou Andrew M.
McGill George E.
Raymond Carol A.
Smrekar Suzanne E.
No associations
LandOfFree
Correlated Magnetic and Gravity Anomalies West of the Isidis Basin, Mars and Implications for Plains Magnetism 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 Correlated Magnetic and Gravity Anomalies West of the Isidis Basin, Mars and Implications for Plains Magnetism, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Correlated Magnetic and Gravity Anomalies West of the Isidis Basin, Mars and Implications for Plains Magnetism will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1177663