Among the mysteries unearthed by Diviner is the apparent complete lack of pristine lunar mantle on the surface. (sciencemag.org)
However, the data have also revealed the presence of highly evolved, silica - rich lunar soils in kilometer - scale and larger exposures, expanded the compositional range of the anorthosites that dominate the lunar crust, and shown that pristine lunar mantle is not exposed at the lunar surface at the kilometer scale. (science.sciencemag.org)
«Still hot inside the Moon: Tidal heating in the deepest part of the lunar mantle.» (sciencedaily.com)