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Updated: May 11, 2026
06:14
Simulating Imaging of Large Scale Radio Arrays on the Lunar Surface
Published on: July 30, 2020
The origin of lunar mascon basins
H J Melosh1, Andrew M Freed, Brandon C Johnson
1Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907, USA. jmelosh@purdue.edu
Science (New York, N.Y.)
|June 1, 2013
Summary
Lunar mass concentrations (mascons) result from impact basin excavation, collapse, and isostatic adjustment. Gravity Recovery and Interior Laboratory (GRAIL) data reveal bull's-eye gravity patterns linked to these processes and melt pool cooling.
Area of Science:
- Planetary Science
- Geophysics
- Lunar Geology
Background:
- Lunar mass concentrations (mascons) are regions of positive gravity anomalies on the Moon.
- Previous studies suggested mascons originated from impact processes but lacked detailed explanation.
- The Gravity Recovery and Interior Laboratory (GRAIL) mission provided high-resolution gravity data.
Purpose of the Study:
- To clarify the origin of lunar mascons using GRAIL gravity data.
- To explain the characteristic bull's-eye gravity anomaly patterns associated with impact basins.
- To model the geophysical processes responsible for mascon formation.
Main Methods:
- Analysis of high-resolution free-air gravity anomalies from GRAIL.
- Simulation of impact basin formation using hydrocode modeling.
- Modeling of subsequent viscoelastic relaxation and cooling using finite-element analysis.
Main Results:
- Observed bull's-eye gravity patterns (central positive, negative collar, outer positive annulus) over lunar impact basins.
- Demonstrated that these patterns arise from impact excavation, collapse, and isostatic adjustment.
- Identified the role of a cooling and contracting voluminous melt pool in shaping the gravity signature.
Conclusions:
- Lunar mascons are a direct consequence of large impact events followed by geological relaxation and cooling.
- Key parameters influencing mascon gravity signatures include impactor energy, lunar thermal gradient, crustal thickness, and volcanic fill.
- The study provides a comprehensive geophysical model for mascon formation, validated by GRAIL data.
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