PERMEABILITY AT YELLOWSTONE: A NATURAL ANALOG FOR YUCCA MOUNTAIN PROCESSES

摘要

Matrix permeability measurements, fracture andrnvein characterization, and petrographic examination ofrncore samples from two U.S. Geological Survey (USGS)rnresearch holes at Yellowstone National Park were usedrnto evaluate the effects of lithology and hydrothermalrnalteration on permeability. Variations in porosity andrnmatrix permeability in the Y-5 and Y-8 cores arernprimarily controlled by lithology. Fluid flow in rocksrnwith low matrix permeability appears to be controlled byrnfractures, which are more abundant in these lithologies.rnWater-rock interaction at Yellowstone has resulted inrnextensive hydrothermal mineralization (especially alongrnveins and fractures) and the formation of self-sealedrnzones. Less extensive water-rock interaction is predictedrnfor the potential Yucca Mountain repository, due tornunsaturated conditions and lower heat flux.