Abstract
We conducted hydrothermal flow-through experiments to observe silica precipitation on granite substrates so as to understand the controls and mechanism of textural development of quartz veins. The precipitation conditions were 400-430 degreeC and 31 MPa, at which quartz solubility, CSi, ,qtz,eq is 80-100 ppm. The various Si-saturated solutions were initially created by dissolution of sands of quartz, amorphous silica and granite at 350-370 degreeC. It is revealed that the precipitated silica species (quartz, cristobalite and amorphous silica) and their textures generally vary depending on Si concentration in the solution and precipitation sites, indicating that the texture of natural quartz veins is suggestive of chemical compositions of the solutions during vein formation.
