Abstracts of Annual Meeting of the Geochemical Society of Japan

We need the amounts of ²⁶Al productions in meteorites in space to determine the terrestrial ages of meteorites. The amount of ²⁶Al productions were estimated by major elemental compositions of meteorites or cosmic-ray fluxes.
Here we present a new production rate of ²⁶Al that is applicable for not only chondrites but also HED meteorites. We estimated the amount of productions of ²⁶Al by major elemental compositions in meteorites based on the correlation between ²⁶Al contents and elemental compositions in nineteen meteorite samples fallen recently.

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Anomalous Ca-Al-Fe-rich spherical inclusion (CAFI) is found from the Vigarano CV3 chondrite. The CAFI has an igneous texture, and occupied by large amounts of end-member and coarse-grained hercynite grains. The CAFI includes refractory phases such as grossite and perovskite. However melilite and Mg-spinel, that are common phases in the normal CAI, are very rare. Another unique characteristic of the CAFI is the presence of dmitryivanovite in its core, which has been formed by shock metamorphism of a low-pressure form of CaAl2O4 that was originally crystallized from the molten droplet. The Ca-Al-Fe-rich characteristic of the CAFI may suggest that its precursor has a genetic link with CH/CB chondrites which contain abundant Fe-metal and grossite-rich CAIs.

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we investigated the association of heavy REE of Yb with yeast S. cerevisiae grown in P-rich medium after exposure for 2 h, 24 h, 48 h, 72h, 96h and 120 h to Yb(III) solution at pH of 3, 4 or 5. These results suggest that the sorbed Yb on the cell surfaces reacted with P released from inside of the yeast cell, resulting in the formation of Yb-phosphate mineral like. This post sorption process on the microbial cell surface should be a key role to constrain the long-term migration of REEs and trivalent actinides in geological repository.

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Recently, CO₂ underground sequestration has been getting a lot of attention as a method of reducing CO₂ emissions causing global warming.
This research is a basic study of CO₂ underground sequestration to clarify CO₂ behavior in the underground, assuming a case of injecting CO₂ into an aquifer of about 1000 meters in depth. For understanding the behavior of CO₂, it is necessary to consider water-rock-CO₂ reaction. However, there is little research of water-rock-CO₂ reaction experiments (CO₂ dissolution experiments). The details about the influence of CO2 on the dissolution reaction of the rocks are still uncertain.
In this study, basalt was assumed to be the host-rock of the sequestration site and experiments of basalt dissolution reaction were conducted in a water-rock-CO₂ system to examine the capabilities of basalt for CO₂ underground sequestration through the experimental reseach and the simulation.It was confirmed that the dissolution rate constant of basalt was larger than that of granite of Ito(2008). In addition, it was found the dissolution rate constant is related to pH and cooling rate of basaltic glass.For the geological CO₂ underground sequestration, we expect the carbon fixation by water-rock-CO₂ reaction in underground, basalt can be thought and expected of the host rock by the carbon fixation since it calculates based on the dissolution rate constant obtained from the experiment. In the simulation, basalt could begin the carbon fixation by mineral trapping in about 25 years and fixated about 95% of CO₂ injected into underground.

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