USGS Home
Contact USGS
Search USGS

U.S. GEOLOGICAL SURVEY
Data Series 280

Strontium Isotopic Composition of Paleozoic Carbonate Rocks in the Nevada Test Site Vicinity, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California

Prepared in cooperation with the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, Office of Environmental Management under Interagency Agreement, DE-AI52-07NA28100

By James B. Paces, Zell E. Peterman, Kiyoto Futa, Thomas A. Oliver, and Brian D. Marshall

Download the report (PDF, 2 MB)

Table of Contents

Conversion Factors, Datum, Definitions, and Abbreviations and Acronyms

Abstract

Introduction

Analytical Methods

Major and Trace Element Chemistry

Strontium Isotopic Compositions

Summary and Conclusions

Acknowledgments

References Cited

Figures

Figure 1. Location of borehole and outcrop samples from the Nevada Test Site region; in and adjacent to the Nevada Test Site; and Bare Mountain and the Funeral Mountains, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California.

Figure 2. Principal pre-Tertiary stratigraphic units and associated hydrogeologic units sampled in Nevada Test Site boreholes, Nye County, Nevada.

Figure 3. Variation in strontium isotopic composition (⁸⁷Sr/⁸⁶Sr) of seawater during part of the Phanerozoic and Late Proterozoic based on analyses of unaltered brachiopods, belemnites, and conodonts from various locations worldwide.

Figure 4. Relation between magnesium oxide (MgO) and calcium oxide (CaO) concentrations in acid leachates of borehole samples, Nevada Test Site, Nye County, Nevada.

Figure 5. Relation between silicon dioxide (SiO₂) and aluminum oxide (Al₂O₃) concentrations and between silicon dioxide and mole percent calcite (CaCO₃) in acid leachates of borehole samples, Nevada Test Site, Nye County, Nevada.

Figure 6 .Relation between strontium (Sr) concentration and mole percent calcite (CaCO₃) in acid leachates of borehole samples, and distribution of strontium concentrations for acid leachates, Nevada Test Site, Nye County, Nevada.

Figure 7. Relation between rubidium (Rb) and silicon dioxide (SiO₂) concentrations in acid leachates of borehole samples and between rubidium/strontium (Rb/Sr) concentration ratios and mole percent calcite (CaCO₃) in acid leachates of borehole samples, Nevada Test Site, Nye County, Nevada.

Figure 8 .Relation between strontium (Sr) and zirconium (Zr) concentrations, strontium and rubidium (Rb) concentrations, zirconium and rubidium concentrations for bulk-rock outcrop samples, and the frequency distribution of strontium concentrations for bulk-rock outcrop samples with zirconium concentrations less than or equal to 20 micrograms per gram, Nevada Test Site and adjacent areas, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California.

Figure 9. Distribution of strontium isotopic compositions (⁸⁷Sr/⁸⁶Sr) measured in borehole and outcrop samples, Nevada Test Site and adjacent areas, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California.

Figure 10. Relation between strontium isotopic compositions (⁸⁷Sr/⁸⁶Sr) and reciprocal strontium concentrations for acid leachates of borehole samples and ⁸⁷Sr/⁸⁶Sr and silicon dioxide (SiO₂) concentrations for acid leachates of borehole samples, Nevada Test Site, Nye County, Nevada.

Figure 11. Relation between δ⁸⁷Sr_t, and depositional age for acid leachates of borehole and outcrop samples, Nevada Test Site and adjacent areas, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California.

Figure 12. Spatial distribution of δ⁸⁷Sr_t, values for borehole and outcrop samples from the Nevada Test Site vicinity, and in and adjacent to the eastern part of the Nevada Test Site, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California.

Tables

Table 1. Ages and seawater strontium isotopic composition (⁸⁷Sr/⁸⁶Sr) of stratigraphic units present in the Nevada Test Site region, southern Nevada.

Table 2. Locations of boreholes from which core samples were obtained at the Nevada Test Site, Nye County, Nevada.

Table 3. Description of samples analyzed for strontium isotopic compositions from boreholes at the Nevada Test Site, Nye County, Nevada.

Table 4. Locations, stratigraphic unit designations, and descriptions of outcrop samples analyzed for strontium isotopic compositions from the Nevada Test Site vicinity, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California.

Table 5. Oxide and elemental concentrations and strontium isotopic compositions (⁸⁷Sr/⁸⁶Sr) of nitric-acid leachates of core samples from boreholes at the Nevada Test Site, Nye County, Nevada.

Table 6. Bulk-rock analyses of selected trace element concentrations and strontium isotopic compositions (⁸⁷Sr/⁸⁶Sr) in outcrop samples collected in the early 1990s from the Nevada Test Site vicinity, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California.

Table 7. Selected trace element concentrations and strontium isotopic compositions (⁸⁷Sr/⁸⁶Sr) in core samples from boreholes UE‑25 a #3 and UE-25 p #1, Nevada Test Site, Nye County, Nevada.

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

Download the report (PDF, 2 MB)

Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 7.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.

Send questions or comments about this report to the author, J.B. Paces, (303) 236-0533.