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The origin of lunar mascons - Analysis of the Bouguer gravity associated with GrimaldiGrimaldi is a relatively small multi-ringed basin located on the western limb of the moon. Spacecraft free-air gravity data reveal a mascon associated with the inner ring of this structure, and the topographic correction to the local lunar gravity field indicates a maximum Bouguer anomaly of +90 milligals at an altitude of 70 kilometers. Approximately 20% of this positive Bouguer anomaly can be attributed to the mare material lying within the inner ring of this basin. From a consideration of the Bouguer gravity and structure of large lunar craters comparable in size to the central basin of Grimaldi, it is suggested that the remaining positive Bouguer anomaly is due to a centrally uplifted plug of lunar mantle material. The uplift was caused by inward crustal collapse which also resulted in the formation of the concentric outer scarp of Grimaldi. In addition, an annulus of low density material, probably a combination of ejecta and in situ breccia, is required to fully reproduce the Bouguer gravity signature across this basin. It is proposed that Grimaldi supplies a critical test in the theory of mascon formation: crustal collapse by ring faulting and central uplift to depths of the crust-mantle boundary are requisites
Document ID
19820055505
Document Type
Conference Proceedings
Authors
Phillips, R. J. (Lunar and Planetary Institute Houston, TX, United States)
Dvorak, J. (U.S. Geological Survey Menlo Park, CA, United States)
Date Acquired
August 10, 2013
Publication Date
January 1, 1981
Subject Category
LUNAR AND PLANETARY EXPLORATION
Meeting Information
Multi-ring basins: Formation and evolution(Houston, TX)
Funding Number(s)
CONTRACT_GRANT: NAS7-100
CONTRACT_GRANT: NASW-3389
Distribution Limits
Public
Copyright
Other