Orbital chemistry—Lunar surface analysis from the X-ray and gamma ray remote sensing experiments

Coincidence in time of the Imbrium basin impact and Apollo 15 KREEP volcanic flows: The case for impact-induced melting

“…Adler and Trombka, 1977;Spudis, 1978;Metzger et al, 1979). As shown by Spudis (1978), the chemical data are consistent with the formation being of the composition of a KREEP basalt, that is, an aluminous basalt with elevated levels of incompatible element abundances.…”

Petrogenesis and chronology of lunar meteorite Northwest Africa 4472: A KREEPy regolith breccia from the Moon

“…It has been argued by some workers that Mg-Suite plutons may form a significant component of the lower lunar crust (Spudis et al, 1999(Spudis et al, , 2000. Remote sensing observations of the lunar surface by the Apollo Gamma-Ray Spectrometer experiment (Adler and Trombka, 1977;Arnold et al, 1977;Metzger et al, 1977;Plate 2.1 of BVSP, 1981) and the Lunar Prospector Gamma-Ray Spectrometer (Lawrence et al, 2002(Lawrence et al, , 2003Prettyman et al, 2006) mapped out the abundances and spatial distribution of Th, Sm and K, which can be used as tracers for surficial outcrops of KREEP-rich material, and MgO, which is a tracer for Mg-Suite deposits (Berezhnoy et al, 2006;Prettyman et al, 2006). These studies revealed that there is an enhancement of KREEP-rich and Mg-rich regoliths concentrated on the nearside of the Moon in the region termed by Jolliff et al (2000) as the Procellarum KREEP Terrane (PKT).…”

Laboratory experiments of particle size effect in X-ray fluorescence and implications to remote X-ray spectrometry of lunar regolith surface

“…In the same manner, the irradiation of atmosphere-free planetary surfaces by solar X-rays produces XRF excitation characteristic of elements. Major elemental mapping in planets can be carried out with concurrent observation of X-rays from the Sun and the planet, as was proven in the Apollo 15 and 16 missions (e.g., Adler and Trombka, 1977). This method has also been used in planetary missions such as the Near-Earth Asteroid Rendezvous-Shoemaker (Trombka et al, 2000;Nittler et al, 2001), Hayabusa , and SMART-1 (Kellett et al, 2006;Grande et al, 2007).…”