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Understanding Geohydrology - Research Goal 1

Understanding any geohydrologic system requires characterization of the geometry and properties of geologic materials and structures at the surface and in the subsurface. Cenozoic basin-fill can have great lithologic diversity and large variation in hydrologic behavior. Surficial deposits that may not be representative of the basin-filling history often cover deeper basin fill units. In order to provide a useable framework for hydrologic flow models, it is necessary to add the third dimension; geologic maps of surficial materials alone are not sufficient to characterize the basin fill and basin depositional history. Digital and conceptual models of the hydrogeologic framework must describe the surficial and subsurface stratigraphy, lithology, structural heterogeneity, and the spatial and depth variability of these elements.

The Amargosa Desert and Pahrump basins in southern Nevada and southeastern California are a critical part of the regional ground-water flow system that includes Death Valley, CA, the Nevada Test Site and the potential high-level nuclear waste underground repository at Yucca Mountain, NV. Most of the ground-water in this flow system either discharges within the Amargosa Desert basin or flows through the two basins en route to discharge points in Death Valley.

Location of the Amargosa nd Pharump valleys

Over the past few years, effort has gone into obtaining, processing, and interpreting subsurface geologic and geophysical data from these basins. Over this same time period, new geologic maps, stratigraphic and tectonic interpretations have been produced for the region that includes these basins by the Death Valley project ( The goal of this task is to integrate available surface and subsurface data and interpretations to produce detailed 3D representations of the basin fill within these two basins. For each basin, geologic materials will be evaluated in terms of their hydrologic significance and defined in a 3D digital representation. Activities will focus on characterizing both surface geologic materials, which control surface-water flow and ground-water recharge, and subsurface geologic materials, which comprise the geologic framework of aquifer materials and properties.

The project addresses these issues on an individual case basis and responds to requests for information as funding allows.

Research Products for Goal 1

Sweetkind, D.S., Fridrich. C.J., and Taylor, E., 2001, Facies analysis of Tertiary basin-filling rocks of the Death Valley regional ground-water system and surrounding areas, Nevada and California: U.S. Geological Survey Open-File Report 01-400, 55 p. Available online at:

Sweetkind, D.S., Taylor, E., and Putnam H., 2003, Stratigraphic inferences derived from borehole data of Tertiary basin-filling rocks of the Pahrump Valley basin, Nevada and California: U.S. Geological Survey Open-File Report 2003-03-051, 30 p. Available online at:

Sweetkind, D.S., Belcher, W.R., and Faunt, C.C., 2002, Three-Dimensional Geological Mapping and Hydrogeologic Framework Construction, Death Valley Ground-Water Flow System, Nevada And California, in, Thorleifson, L.H. and Berg, R.C., Three-Dimensional Geological Mapping for Groundwater Applications: Geological Survey of Canada Open-File Report 1449, p. 71-74.

Belcher, W.R., Sweetkind, D.S., and Elliott, P.E., 2002, Probability Distributions of Hydraulic Conductivity for the Hydrogeologic Units of the Death Valley Regional Ground-Water Flow System, Nevada and California: U.S. Geological Survey Water-Resources Investigations Report 02-4212.Available online at:

Scheirer, D.S., Sweetkind, D.S., and John Miller, 2010, Multiple phases of basin formation along the Stateline fault system in the Pahrump and Mesquite Valleys, Nevada and California: Geosphere, April, 2010, v. 6, no. 2, p. 93-129, doi: 10.1130/GES00520.1.


Jachens, R.C., Sweetkind, D.S., Langenheim, V.E., Phelps, G. A., and McKee, E.H., 2002, Building hydrogeologic framework models of basins: contributions from geophysically-based 'elements': Geological Society of America Abstracts with Programs, v. 34, p. 394.

Sweetkind, D.S., 2002, Approaches to constructing 3D property models for the basin-fill component, arid southwestern U.S.: Geological Society of America Abstracts with Programs, v. 34, p. 393.

Sweetkind, D.S., Faunt, C.C., and Phelps, G., 2002, Evaluation and Quantification of Uncertainty Inherent in Geologic Data, Interpretations and Conceptual Models: EOS, Transactions, American Geophysical Union, v. 83, p. F497.

Phelps, Geoffrey, 2002, Sensitivity analysis of a gravity inversion model in Frenchman Flat basin, NV: EOS, Transactions, American Geophysical Union, v. 83, p. F1242.


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