Lunar prospector measurements of the distribution of incompatible elements gadolinium, samarium and thorium

Lunar Prospector neutron spectrometer (NS) and gamma ray spectrometer (GRS) observations have been used to map out the distribution of incompatible elements on the lunar surface. Specifically, the GRS data provide maps of the distribution of thorium and potassium while the NS data provide informatio...

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Bibliographic Details
Main Authors: Elphic, R.C., Lawrence, D.J., Feldman, W.C., Barraclough, B.L., Maurice, S., Binder, A.B., Lucey, P.G.
Language:unknown
Published: 2009
Subjects:
66 PHYSICS
MOON
CHEMICAL COMPOSITION
GADOLINIUM
SAMARIUM
THORIUM
NEUTRON SPECTROMETERS
GAMMA SPECTROMETERS
SPATIAL DISTRIBUTION
Aitken
South Pole
South pole
Online Access:http://www.osti.gov/servlets/purl/334321
https://www.osti.gov/biblio/334321
Description
Summary:Lunar Prospector neutron spectrometer (NS) and gamma ray spectrometer (GRS) observations have been used to map out the distribution of incompatible elements on the lunar surface. Specifically, the GRS data provide maps of the distribution of thorium and potassium while the NS data provide information on the distribution of iron and titanium, and the rare earth elements gadolinium and samarium. Using results of analysis of Celementine spectral reflectance (CSR) data, the Fe- and Ti-contributions to the NS data can be removed, leaving primarily rare earth element contributions from Gd and Sm. The Th and K maps correlate with the inferred Gd and Sm maps (r {approximately} 0.93), but there are regions of significant disagreement. One of these is in the KREEP-rich circum-Imbrium ring. No clear explanation has emerged for this disagreement, though Th, K, Gd and Sm have differing degrees of incompatibility. These results clearly are important to discussions of the geochemistry of the Procellarum-Imbrium Th-rich Terrane and the South-Pole-Aitken Terrane.

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