Leaching behaviors of the rocks in the Shimanto belt and their roles on calcite precipitation in hydrothermal conditions

Abstract

It is considered to be difficult to precipitate calcite in reasonable timescale for carbon storage. In contrast, calcite veins are common in natural geological settings. The purpose of this study is to understand the mechanism of calcite precipitation in hydrothermal environments. The leaching experiments revealed that several cations were leached from the rocks, resulting in alkaline fluids supersaturated with calcite. The flow-through experiments revealed that the acidic solution made by CO₂ bubbling was undersaturated with calcite. Alkaline fluids with NaHCO₃ reacted with pelitic rocks to produce calcite crystals with size of 0.01 mm precipitated on the calcite substrates.