The Sm-Nd history of KREEPSm-Nd whole rock measurements on a variety of KREEP-rich samples from different landing sites are reported. Despite a variation of Nd and Sm concentrations of almost a factor of 3, the Sm-Nd ratios, as well as the Nd-143/Nd-144 values, show an extremely close grouping. No systematic differences between samples from different landing sites are resolved. These results are taken to be indicative of a moon-wide process having been responsible for the generation of the KREEP source reservoir, 4.36 plus or minus 0.06 AE ago, as estimated from model age calculation.
Document ID
19790055126
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Lugmair, G. W. (California Univ. La Jolla, CA, United States)
Carlson, R. W. (California, University La Jolla, Calif., United States)