Open AccessAnalysis of fractures in volcanic cores from Pahute Mesa, Nevada Test Site
Author(s) -
S.L. Drellack,
Lance Prothro,
K.E. Roberson
Publication year - 1997
Language(s) - English
Resource type - Reports
DOI - 10.2172/623041
Subject(s) - geology , groundwater , hydraulic conductivity , groundwater flow , volcano , test site , water table , permeability (electromagnetism) , hydrology (agriculture) , geotechnical engineering , mining engineering , aquifer , soil science , seismology , soil water , genetics , membrane , biology
The Nevada Test Site (NTS), located in Nye County, southern Nevada, was the location of 828 announced underground nuclear tests, conducted between 1951 and 1992. Approximately one-third of these tests were detonated near or below the water table. An unavoidable consequence of these testing activities was introducing radionuclides into the subsurface environment, impacting groundwater. Groundwater flows beneath the NTS almost exclusively through interconnected natural fractures in carbonate and volcanic rocks. Information about these fractures is necessary to determine hydrologic parameters for future Corrective Action Unit (CAU)-specific flow and transport models which will be used to support risk assessment calculations for the U.S. Department of Energy, Nevada Operations Office (DOE/NV) Underground Test Area (UGTA) remedial investigation. Fracture data are critical in reducing the uncertainty of the predictive capabilities of CAU-specific models because of their usefulness in generating hydraulic conductivity values and dispersion characteristics used in transport modeling. Specifically, fracture aperture and density (spacing) are needed to calculate the permeability anisotropy of the formations. Fracture mineralogy information is used qualitatively to evaluate diffusion and radionuclide retardation potential in transport modeling. All these data can best be collected through examination of core samples