Mantles of rocky planets are dominantly composed of olivine and its high-pressure polymorphs, according to seismic data of Earth's interior, the mineralogy of natural samples, and modelling results. The missing mantle problem represents the paucity of olivine-rich material among meteorite samples and remote observation of asteroids, given how common differentiated planetesimals were in the early Solar System. Here we report the discovery of new olivine-rich meteorites that have asteroidal origins and are related to V-type asteroids or vestoids. Northwest Africa 12217, 12319, and 12562 are dunites and lherzolite cumulates that have siderophile element abundances consistent with origins on highly differentiated asteroidal bodies that experienced core formation, and with trace element and oxygen and chromium isotopic compositions associated with the howardite-eucrite-diogenite meteorites. These meteorites represent a step towards the end of the shortage of olivine-rich material, allowing for full examination of differentiation processes acting on planetesimals in the earliest epoch of the Solar System.

The short-lived radionuclide aluminium-26 (26Al) isotope is a major heat source for early planetary melting. The aluminium-26 - magnesium-26 (26Al-26Mg) decay system also serves as a high-resolution relative chronometer. In both cases, however, it is critical to establish whether 26Al was homogeneously or heterogeneously distributed throughout the solar nebula. Here we report a precise lead-207 - lead-206 (207Pb-206Pb) isotopic age of 4565.56 ± 0.12 million years (Ma) for the andesitic achondrite Erg Chech 002. Our analysis, in conjunction with published 26Al-26Mg data, reveals that the initial 26Al/27Al in the source material of this achondrite was notably higher than in various other well-preserved and precisely dated achondrites. Here we demonstrate that the current data clearly indicate spatial heterogeneity of 26Al by a factor of 3-4 in the precursor molecular cloud or the protoplanetary disk of the Solar System, likely associated with the late infall of stellar materials with freshly synthesized radionuclides.