11:15 AM - 11:30 AM
[HCG25-09] Influences of faulting and hydrothermal alteration on matrix diffusion in granitic rocks
Keywords:matrix diffusion, fault, hydrothermal alteration, granitic rocks
Six granitic rock samples (three samples are altered rocks and others are non-altered rocks) are obtained from ground level -300m in Mizunami Underground Research Laboratory (MIU) located in Mizunami city Gifu prefecture, central Japan. Detailed observations and through-diffusion experiments to use uranine as a tracer material provide two results, 1) Porosities and effective diffusivities of samples located near faults show high value compared with samples from site which are unaffected by faulting and 2) The decrease in porosities and effective diffusivities of samples located near fault is related to the increase in the percentage of secondary mineral.
This result suggests that faulting and hydrothermal alteration has potentials of controlling the distribution of microscopic voids and having an effect on the matrix diffusion rates.