Dawsonite and Other Carbonate Veins in the Cretaceous Izumi Group, SW Japan: A Natural Support for Fracture Self-Sealing in Mudstone Caprock in CGS?

Dawsonite-bearing carbonate veins are abundant in a compact mudstone layer of the lower part of the Izumi Group, SW Japan. The mode of occurrence of the veins probably indicates fracturing and mineral sealing associated with upwelling of CO2-rich fluid evolved in the reservoir beneath. The carbonate veins studied here can be a natural support to fracturing and healing of mudstone caprock in the CO2 geological storage.