So far there are no samples from the moon mantle. The Apollo astronauts and the Soviet robot mission brought only surface rocks to Earth. Also, some meteorites hit on the earth come from the moon. Only certain information about the interior of the moon is available: volcanic eruptions on the moon sometimes brought iron-rich melts to the surface, which can not come from the lunar crust. This is on average seventy kilometers thick? three times as powerful as the earth's crust? and consists mainly of the silica material feldspar. By contrast, the research on the structure of the moon mantle under the crust has so far been in the dark.
According to the study, olivine comes from inside the moon and is a result of crater formation. This is supported by the fact that the crust is significantly thinner at thirty to fifty kilometers in the crater area than anywhere else, write the scientists. Upon impact of a meteorite, most of the crust may have been blown away at the point of impact. Subsequently, the exposed mantle was again covered by lava only inside the crater.
Alternatively, the olivine-rich material could have come from lower depths of the lower crust and ascended in the molten state. However, after a more detailed analysis, the scientists excluded this variant: The composition of the rocks of the crater rim does not match the components of the lower crust. displaySatoru Yamamoto (Center for Global Environmental Research, Ibaraki) et al .: Nature Geoscience, online pre-release, doi: 10.1038 / ngeo897 ddp / science.de? David Köndgen