Water is abundant as solid ice in the Solar System and plays an important role in its evolution. Water is preserved in some primitive meteorites named carbonaceous chondrites as hydroxyl and/or H2O molecules in hydrous minerals, but has not been found as liquid. To uncover such liquid, Professor Akira Toyama's team performed systematic analyses using synchrotron-based X-ray computed nanotomography and transmission electron microscopy with a cryo-stage of the aqueously-altered carbonaceous chondrite Sutter’s Mill. They discovered CO2- bearing fluid (CO2/H2O > ~0.15) in a nano-sized inclusion incorporated into a calcite crystal, appearing as CO2 ice and/or CO2 hydrate at 173 K. This fluid inclusion was incorporated into the calcite during its precipitation from a fluid, which formed by melting of CO2-bearing ice. This is direct evidence of dynamic evolution of the Solar System, requiring the Sutter’s Mill parent body to have formed outside the CO2 snow line and later transported to the inner Solar System due to Jupiter’s orbital instability.
The article, to which the Guangzhou Institute of Geochemistry, Chinese Academy of Sciences has contributed as a collaborative unit, was published online by Science Advance on April 21, 2021.
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