Scientists have examined a stone from the Sutter’s Mill parent body that was collected before heavy rain fell on the site of the Sutter’s Mill impact. The study shows that Oldhamite is present in the sample, while samples that were rained on do not contain the mineral. The study provides new insights about composition of the parent body from which the Sutter’s Mill stones originated, and the processes that shaped its mineral composition. The study also highlights the importance of collecting samples as quickly as possible after a meteorite fall has occurred, thereby limiting the effects of terrestrial alteration.

The paper, “Extraterrestrial formation of oldhamite and portlandite through thermal metamorphism of calcite in the Sutter’s Mill carbonaceous chondrite,” was published in the journal American Mineralogist. The work was supported by NASA Astrobiology through the Exobiology & Evolutionary Biology Program and the Emerging Worlds Program. The NASA Astrobiology Program provides resources for Emerging Worlds and other Research and Analysis programs within the NASA Science Mission Directorate (SMD) that solicit proposals relevant to astrobiology research.