HR: 1340h
AN: P23A-0226    [Abstracts]
TI: Correlations Between Magnetic Anomalies and Surface Geology Antipodal to Lunar Impact Basins
AU: * Richmond, N C
EM: nic@lpl.arizona.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093-0225 United States
AU: Hood, L L
EM: lon@lpl.arizona.edu
AF: Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 United States
AB: Previous work has shown that the strongest concentrations of lunar crustal magnetic anomalies are located antipodal to four large, similarly aged impact basins (Orientale, Serenitatis, Imbrium and Crisium). Here, we report results of a correlation study between magnetic anomaly clusters and geology in areas antipodal to Imbrium and Orientale. Only these areas have been selected due to a) limited Lunar Prospector magnetometer data coverage of the area antipodal to Serenitatis, and b) the location of the Crisium antipode, which is dominated by ejecta deposits from the more recent Orientale impact. Unusual geologic terranes have been mapped antipodal to both Orientale (furrowed and pitted terrane) and Imbrium (material of grooves and mounds). These units have been interpreted to be of seismic or ejecta origin associated with the basin forming impacts. Both regions have many high albedo swirl markings, which have been shown to correlate closely with regions of high crustal magnetisation at other locations. Results indicate a strong correlation between the swirl markings and regions of high magnetisation for both the Imbrium and Orientale antipodes. In addition, the furrowed and pitted terrane, material of grooves and mounds and Mare Ingenii (antipodal to Imbrium) show a correlation with high magnitude crustal magnetic anomalies. Mare Ingenii is on the south west edge of the material of grooves and mounds and may overlay that unit, with the anomaly sources beneath the mare materials. This is supported by an observed lack of demagnetisation associated with the 61 km Copernican-aged O'Day crater at the edge of Mare Ingenii, which suggests a deep source for the anomalies. Possible source materials and the origin of the magnetisation will be discussed at the conference.
DE: 5420 Impact phenomena (includes cratering)
DE: 5440 Magnetic fields and magnetism
DE: 5470 Surface materials and properties
DE: 6250 Moon (1221)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting