11:00 AM - 1:00 PM
[HSC06-P09] Evaluation of basalt applicability for CO2 storage and enhanced weathering
Keywords:Basalt, Geological CO2 storage, Enhanced weathering, Mineral carbonation, CO2-water-rock interaction, Permeability
Starting from the success of rapid mineralization of CO2 in the Iceland CarbFix project, there has been increasing interest in CO2 storage and enhanced weathering using basalt in recent years. This study aims to obtain knowledge on the applicability of basalt itself to CO2 mineralization as a stage of basic study before proceeding to actual storage and enhanced weathering in Japan.
From the basalt producing areas in Japan, we selected some areas where basaltic ejecta with different activity periods, chemical compositions and occurrences are available. Considering the possibility of site survey and development in the future ocean area, this time focused on surveying and sampling basalts that are thought to have characteristics similar to those of ocean island volcanoes. Specifically, the target area is 1) Iki, Nagasaki prefecture, 2) Sanin region centered on Yamaguchi and Shimane prefectures, 3) Sado island, Niigata prefecture, and 4) central and eastern parts of Hokkaido. Basalts in these areas include not only those with the same chemical composition as CarbFix project in Iceland but also those with various chemical compositions such as Ca, Mg, Fe, K and Si with different quantitative ratios. In the Hokkaido area, systematic sampling was performed for ultramafic rocks, which are significantly richer in Ca and heavy metals than basalt, from non-altered to serpentinite. Each collected rock shows various occurrences such as foamed and dense parts, coarse-grained and fully crystalline minerals, and fine-grained and vitreous (currently altered) minerals.
For the collected rocks, whole rock chemical composition analysis, mineral composition analysis by thin section observation, mineral identification by powder X-ray diffraction, 40Ar/39Ar dating to clarify the activity time, porosity measurement by mercury intrusion method, etc. are proceeding. In the future, based on these results, we plan to screen promising rocks from the viewpoint of mineralization and permeability, and perform quantitative evaluation by reaction experiments in the CO2-water-rock system or CO2 flow experiments.
From the basalt producing areas in Japan, we selected some areas where basaltic ejecta with different activity periods, chemical compositions and occurrences are available. Considering the possibility of site survey and development in the future ocean area, this time focused on surveying and sampling basalts that are thought to have characteristics similar to those of ocean island volcanoes. Specifically, the target area is 1) Iki, Nagasaki prefecture, 2) Sanin region centered on Yamaguchi and Shimane prefectures, 3) Sado island, Niigata prefecture, and 4) central and eastern parts of Hokkaido. Basalts in these areas include not only those with the same chemical composition as CarbFix project in Iceland but also those with various chemical compositions such as Ca, Mg, Fe, K and Si with different quantitative ratios. In the Hokkaido area, systematic sampling was performed for ultramafic rocks, which are significantly richer in Ca and heavy metals than basalt, from non-altered to serpentinite. Each collected rock shows various occurrences such as foamed and dense parts, coarse-grained and fully crystalline minerals, and fine-grained and vitreous (currently altered) minerals.
For the collected rocks, whole rock chemical composition analysis, mineral composition analysis by thin section observation, mineral identification by powder X-ray diffraction, 40Ar/39Ar dating to clarify the activity time, porosity measurement by mercury intrusion method, etc. are proceeding. In the future, based on these results, we plan to screen promising rocks from the viewpoint of mineralization and permeability, and perform quantitative evaluation by reaction experiments in the CO2-water-rock system or CO2 flow experiments.