Abstract
To reduce greenhouse gas, the carbon storage underground has been tried; however, it is considered to be difficult to precipitate calcite in reasonable timescale. In contrast, calcite veins are very common in the oceanic crusts, metamorphic rocks, and accretionary prisms.
The purpose of this study is to understand the controlling factors on calcite precipitation. As a first step, we conducted hydrothermal flow-through experiments to precipitate calcite at 300 ˚C and 30 MPa by using the temperature dependency of solubility.
After the run of 240 h (10 days), the total increase of weight of calcite substrates was 0.051 g. Observation of the surface reveal that euhedral calcite crystals with size of 0.02-0.03 mm grew from the calcite in the substrates. Our results suggest that calcite veins could be formed around 300 ˚C, if fluids saturated with calcite at lower temperature would be brought accompanying with subduction of slabs.
