The unsaturated zone (UZ) in Miocene-age welded tuffs at Yucca Mountain, Nevada, is under consideration as a potential site for the construction of a high-level radioactive waste repository. Secondary calcite and silica minerals deposited on fractures and in cavities in the UZ tuffs are texturally, isotopically, and geochemically consistent with UZ deposition from meteoric water infiltrating at the surface and percolating through the UZ along fractures. Nonetheless, two-phase fluid inclusions with small and consistent vapor to liquid (V:L) ratios that yield consistent temperatures within samples and which range from about 35 to about 80 C between samples have led some to attribute these deposits to formation from upwelling hydrothermal waters. Geochronologic studies have shown that calcite and silica minerals began forming at least 10 Ma and continued to form into the Holocene. If their deposition were really from upwelling water flooding the UZ, it would draw into question the suitability of the site as a waste repository.

Yucca Mountain is under study as a potential site for underground storage of high-level radioactive waste, with the principle goal being the safe isolation of the waste from the accessible environment. This paper addresses the hydrogeologic characteristics of the fault zones at Yucca Mountain, focusing primarily on the central part of the mountain where the potential repository block is located.

From Introduction: "The Tonopah Quadrangle, Nevada (Figure 1), was evaluated to a depth of 1500 m (5,000 ft) to identify geologic environments and delineate areas that exhibit characteristics favorable for uranium deposits."

Appendices containing data on uranium availability in the Tonopah Quadrangle to accompany a report on U.S. uranium resources in Nevada.

From abstract: This data report presents results of ground water and stream sediment reconnaissance in the National Topographic Map Series (NTMS) Death Valley 1 x 2 quadrangle.

Supplementary data containing histograms and cumulative frequency plots for all elements to accompany a report on U.S. uranium resources in California and Nevada.

The following data report presents results of stream surface sediment reconnaissance in the McDermitt and Wells quadrangle, Nevada.

These tables contain data collected from stream sediment reconnaissance in the McDermitt quadrangle.

These tables contain data collected from stream sediment reconnaissance in the Wells quadrangle.

Abstract: The results of analyses of the airborne gamma radiation and total magnetic field survey flown for the region identified as the Tonopah National Topographic Map NJll-5 is presented in Volume I and II of this report. The airborne data gathered is reduced by ground computer facilities to yield profile plots of the basic uranium, thorium and potassium equivalent gamma radiation intensities, ratios of these intensities, aircraft altitude above the earth's surface, total gamma ray and earth's magnetic field intensity, correlated as a function of geologic units. The distribution of data within each geologic unit, for all surveyed map lines and tie lines, has been calculated and is included. Two sets of profiled data for each line are included with one set displaying the above-cited data. The second set includes only flight line magnetic field, temperature, pressure, altitude data plus magnetic field data as measured at a base station. A general description of the area, including descriptions of the various geologic units and the corresponding airborne data, is included also.

Data listings from the area surveyed in a report on the Hot Springs containing averaged record data listings.

Data listings from the area surveyed in a report on the Hot Springs including single record reduced listings.

"This report represents the results of the reconnaissance sampling of the Deep Creek Mountains of western Utah...Samples collected in this study include dry and wet stream sediments and water from available streams, wells, and springs. The samples were analyzed for uranium, as well as 15 to 20 trace element, using neutron activation techniques. In addition, field and laboratory measurements were made on the water samples." (from Abstract)

Purpose and Scope: "The purpose of this study is to provide basic water supply data needed for future evaluation and selection of promising saline water conversion opportunities. This report presents information regarding the present and future supply situation of individual communities. Also presented is information on regional water plans with respect to provisions for municipal water supply."

This report summarizes the gravity data of the Area 12, Nevada Test Site.

None

Report on an evaluation of the Sand Springs Range as a possible location for an underground nuclear study (Shoal Event). Various tests to determine the site's suitability included aerial photography and mapping of the area through various means; drilling and bulldozing to conduct mineralogical and other physical evaluations; gravity, aeromagnetic, and refraction surveys; and studies related to the hydrology of the location and surrounding areas.

Plates documenting results of some tests performed during the site evaluation of the Sand Springs Range including aerial photography, various types of mapping and surveying of the physical and hydrological aspects of the location, and other supplementary materials.

From introduction: "This report was compiled to bring together the well data collected by the U.S. Geological Survey since 1960. This compilation includes data on 63 wells and test holes which were drilled since the Moore reports were prepared, or which were deepened or otherwise modified since 1960."

The following report provides a geological map of the Quartet Dome quadrangle in Nye county, Nevada.

a geologic map of the Quartet Dome quadrangle, Nye County, Nevada

Introduction: Geologic studies by the U.S. Geological Survey in support of the U.S. Air Force's Project Pluto in Area 401 of the Nevada Test Site were made on behalf of the U.S. Atomic energy Commission.

From abstract: This report is on the geologic studies in the U12e.07 tunnel for the purpose of determining the structural features, lithographic character, chemical composition, and physical properties of the tuff exposed in the tunnel.

Abstract: Geophysical logs, a summary of contract costs, detailed descriptions of drilling, casing, cementing, and hydraulic testing operations, X-ray mineralogical analyses, physical property analyses, and a detailed lithologic log are presented in the report.