Thorium concentrations in the lunar surface. IV - Deconvolution of the Mare Imbrium, Aristarchus, and adjacent regionsSeveral fields of orbital gamma ray spectroscopy data have been deconvolved in order to model the distribution of Th over the Mare Imbrium and northern Oceanus Procellarum portions of the Apollo 15 lunar ground track, which in combination with a prior study of the Apenninus region covers a continuous swath from 10 deg E to 60 deg W in the northwest quadrant. The crater of the Aristarchus region dominates the Th distribution, with a concentration of 20 ppm, and substantial enhancements are also found in the mare regions around Brayley and at the ejecta blankets of Timocharis and Lambert. The existence of enhanced Th concentrations in mare basalt regions suggests that reservoirs of some late stage mare basalts incorporated KREEP-rich material during formation or transit.
Document ID
19830040069
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Etchegaray-Ramirez, M. I. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Metzger, A. E. (Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Haines, E. L. (California Institute of Technology, Jet Propulsion Laboratory, Pasadena CA, United States)
Hawke, B. R. (Hawaii, University Honolulu, HI, United States)