Computation of porosity and water content from geophysical logs, Yucca Mountain, Nevada

Nelson, P.H.

doi:10.3133/ofr9678

Cited by 2 publications

(1 citation statement)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Borehole WT‐2 is located in a short, east‐trending wash in central Yucca Mountain, and Borehole H‐3 is located on Yucca Crest. The models extended from the ground surface to the water table, with a constant vertical grid spacing of 5 m. Although more than 30 separate hydrogeologic units have been identified in the vadose zone at Yucca Mountain (Flint, 1998), the models presented here used a simplified stratigraphy that includes five units, with the properties given in Table 1 Information on the depths of the stratigraphic intervals, major welding changes, and zones of zeolite development were taken from unpublished lithologic logs compiled by the U.S. Geological Survey (R. Spengler, personal communication, 1997) and from geophysical logs (Nelson, 1994, 1996). The simulations assumed a passive gas phase.…”

Section: Analysis Of Deep Temperature Profiles Underlying Arid Mountamentioning

confidence: 99%

Temperature‐Profile Methods for Estimating Percolation Rates in Arid Environments

Constantz

Tyler

Kwicklis

2003

Vadose Zone Journal

View full text Add to dashboard Cite

Percolation rates are estimated using vertical temperature profiles from sequentially deeper vadose environments, progressing from sediments beneath stream channels, to expansive basin‐fill materials, and finally to deep fractured bedrock underlying mountainous terrain. Beneath stream channels, vertical temperature profiles vary over time in response to downward heat transport, which is generally controlled by conductive heat transport during dry periods, or by advective transport during channel infiltration. During periods of stream‐channel infiltration, two relatively simple approaches are possible: a heat‐pulse technique, or a heat and liquid‐water transport simulation code. Focused percolation rates beneath stream channels are examined for perennial, seasonal, and ephemeral channels in central New Mexico, with estimated percolation rates ranging from 100 to 2100 mm d−1. Deep within basin‐fill and underlying mountainous terrain, vertical temperature gradients are dominated by the local geothermal gradient, which creates a profile with decreasing temperatures toward the surface. If simplifying assumptions are employed regarding stratigraphy and vapor fluxes, an analytical solution to the heat transport problem can be used to generate temperature profiles at specified percolation rates for comparison to the observed geothermal gradient. Comparisons to an observed temperature profile in the basin‐fill sediments beneath Frenchman Flat, Nevada, yielded water fluxes near zero, with absolute values <10 mm yr−1. For the deep vadose environment beneath Yucca Mountain, Nevada, the complexities of stratigraphy and vapor movement are incorporated into a more elaborate heat and water transport model to compare simulated and observed temperature profiles for a pair of deep boreholes. Best matches resulted in a percolation rate near zero for one borehole and 11 mm yr−1 for the second borehole.

show abstract

Section: Analysis Of Deep Temperature Profiles Underlying Arid Mountamentioning

confidence: 99%