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U.S. GEOLOGICAL SURVEY
Data Series 297

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Introduction

Rock-sample data are available from holes (boreholes, shafts, tunnels, and drifts) located on and around the Nevada Test Site (NTS), Nye County, Nevada. These data include rock-sample interval locations for nearly 2,600 holes; lithologic descriptions for nearly 1,300 holes; physical and mechanical rock properties for nearly 600 holes; fracture characteristics for nearly 500 holes; and hydraulic properties for nearly 100 holes. Acronyms and abbreviations in common usage at the NTS are described in the auxiliary ‘nts_acr_abv’ worksheets in the databases (appendixes A–E).

Purpose and Scope

This report documents rock samples and data derived from these samples in digital spreadsheets. Specifically, this report presents five databases (rock samples, lithologic descriptions, rock properties, fracture characteristics, and hydraulic properties). Data presented in these databases were obtained from rock samples and compiled from paper records contained in the historical files and from published reports located at the U.S. Geological Survey (USGS) Core Library and Data Center at Mercury (on the NTS) and at the USGS office in Henderson, Nevada.

The many logs and samples presented in this report represent a large investment over many years and are unique, in that in many cases, they cannot be acquired again. Pre-test, in-place conditions, as well as conditions that existed prior and during nuclear testing can not be recreated and rock samples (and associated analysis and interpretations) from the many holes destroyed by testing cannot be recollected. Measurement techniques continuously evolve over time and the methods of interpretation are constantly being revised as new techniques become available. The application of these new methods often depends on the availability of the original subsurface data and the ability of individuals to understand both how these data were collected and how associated interpretations were developed. Documenting these data in a published report will ensure data availability for posterity. Furthermore, the condition of the original paper records is already poor and data are illegible for some records. The continuing deterioration of these records could preclude their availability to future investigators. All subsurface data, regardless of program or application, needs to be archived for future use at the NTS. Only through publication and archiving, can these data be fully developed and utilized in making sound decisions concerning future activities at the NTS and protection of human health and safety.

Background

The NTS (fig. 1) was established by the United States during the 1950s as the primary continental proving ground for nuclear testing and peaceful applications of nuclear explosions (U.S. Congress, 1989). The site, which occupies about 1,375 mi² of south-central Nevada, was chosen by the Atomic Energy Commission (AEC, predecessor to the U.S. Department of Energy [DOE]) primarily because of its remoteness from population centers and because the land was under military control (Fehner and Gosling, 2000). Since 1951, 928 tests have been conducted at the NTS. Of these tests, 828 were detonated underground (U.S. Department of Energy, 2000). In addition to the holes used for underground emplacement of nuclear weapons, many auxiliary holes were drilled and mined adjacent to the emplacement holes for collecting supplemental data. The databases presented in this report represent an accumulation of data from each of these holes.

Geologists, geophysicists, hydrologists, and other specialists have worked in cooperation with the DOE, National Nuclear Security Administration, Nevada Site Office (and its predecessors) and the National Laboratories to provide Earth science data since 1956 (P.P. Orkild, U.S. Geological Survey, written commun., 1987). The USGS and AEC agreed to cooperate in geologic, geophysical, and hydrologic investigations at the NTS under a memorandum of understanding (No. AT (2902)474) dated June 1, 1957. A modification to the memorandum which incorporates the entire agreement (Modification No. 3, Schedule 1 to Appendix A, page 3, item 4), dated April 3, 1959 states:

The USGS Core Library and Data Center was established in temporary quarters during 1959 at Mercury, Nevada, and a permanent facility was built during the late 1960s (G.L. Dixon, U.S. Geological Survey, written commun., 1983). Because the USGS was designated as the caretaker of the rock samples, personnel from the National Laboratories as well as DOE and Department of Defense (DOD) contractors were continually accessing rock samples at the Core Library. This resulted in the USGS amassing paper copies of many of the preliminary results of the rock-sample analyses and interpretations as well as internal and published reports resulting from this work.

Geohydrologic Setting

The NTS is entirely within the Great Basin region of the Basin and Range physiographic province. The region is characterized by mountain ranges with a general north-south orientation separated by basins (valleys) that are filled by accumulations of unconsolidated to partly consolidated sedimentary deposits and underlain by consolidated rocks that also form the surrounding ranges (Stewart, 1980). The unconsolidated rocks at the NTS consist of basin fill and volcanic and sedimentary rocks. Consolidated rocks consist of volcanic, metamorphic and intrusive, siliciclastic, and carbonate rocks. The generalized distribution of rock types in the vicinity of the NTS is shown in figure 2.

The stratigraphic nomenclature at the NTS has evolved over time. The USGS conducted surface-mapping field work between 1958 and 1964 that resulted in the publication of thirty-four 7.5-minute geologic maps (Byers and others, 1989). The stratigraphy and lithology has been continually refined by investigators from various organizations (including DOE/DOD subcontractors, the National Laboratories, and USGS) by inspection of rock samples collected from holes drilled and mined at the NTS and vicinity. This has resulted in many informal units in common usage at the NTS. Volcanic rocks are summarized in Byers and others (1976) and Sawyer and others (1994). Carbonate rocks are summarized in Cole and Cashman (1999). Stratigraphic units are lumped into hydrogeologic units and discussed in IT Corporation (1996a, 1996b), Faunt and others (2004), and Sweetkind and others (2004).

The hydrologic setting of the NTS is similar to that of most of the Basin and Range province. It is characterized by localized aquifers within the alluvial deposits in the eastern, central, and southern parts. Regional aquifers are mostly within complexly folded and faulted limestones and dolomites that underlie the localized aquifers in the eastern and southern parts, but also are within fractured volcanic rocks in the western part of the NTS. Much of the ground-water flow is interbasin; that is, flow is not strictly controlled by the surface topography that defines surface-water drainage basins (Blankennagel and Weir, 1973; Winograd and Thordarson, 1975; Laczniak and others, 1996; Slate and others, 2000; Potter and others, 2002; Workman and others, 2002).

Site Designations

Rock-sample sites are identified primarily by the USGS NTS unique number and secondarily by the NTS area (the NTS is comprised of 26 administrative areas [fig. 1]), a Redbook hole number, and USGS National Water Information System (NWIS) site identification number (U.S. Geological Survey, 2005). A unique number is necessary because spatial (X-Y) coordinates are currently not available for some sites. Site designations are described in the tables listed in the appendixes of this report.

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