Ar-40-Ar-39 Age of an Impact-Melt Lithology in Lunar Meteorite Dhofar 961

The Dhofar 961 lunar meteorite was found in 2003 in Oman. It is texturally paired with Dhofar 925 and Dhofar 960 (though Dhofar 961 is more mafic and richer in incompatible elements). Several lines of reasoning point to the South Pole-Aitken Basin (SPA) basin as a plausible source (Figure 2): Mafic character of the melt-breccia lithic clasts consistent the interior of SPA, rules out feldspathic highlands. Compositional differences from Apollo impact-melt groups point to a provenance that is separated and perhaps far distant from the Procellarum KREEP Terrane SPA "hot spots" where Th concentrations reach 5 ppm and it has a broad "background" of about 2 ppm, similar to lithic clasts in Dhofar 961 subsamples If true, impact-melt lithologies in this meteorite may be unaffected by the Imbrium-forming event that is pervasively found in our Apollo sample collection, and instead record the early impact history of the Moon.