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U.S. GEOLOGICAL SURVEY
Data Series 280

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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.

[Trace element (Rb, Sr, Zr, Ba, La, and Ce) concentrations were determined by X-ray fluorescence on whole-rock samples and are given in micrograms per gram (µg/g). Concentrations below minimum reporting limits are indicated as “0”. “ND” indicates that concentrations were not determined. All strontium isotopic compositions (⁸⁷Sr/⁸⁶Sr) were determined on dilute hydrochloric acid leachates of powdered rock samples with the exception of two samples (map numbers 4 and 5 marked with asterisks) which were determined on whole-rock digestions. ⁸⁷Sr/⁸⁶Sr uncertainties are typically, but not always, dominated by external error associated with reproducibility of the EN–1 standard (±0.00005). Strontium isotopic compositions are also given in delta notation (δ⁸⁷Sr_t) = [(⁸⁷Sr/⁸⁶Sr_sample/⁸⁷Sr/⁸⁶Sr_psw)-1]×1,000, where ⁸⁷Sr/⁸⁶Sr_msw is the value for modern seawater and ⁸⁷Sr/⁸⁶Sr_psw is the value for paleoseawater at the time of deposition. δ⁸⁷Sr_t values for rocks underlying the Wood Canyon Formation were not calculated (NC) because of the very large uncertainties in assigning ages and initial seawater ⁸⁷Sr/⁸⁶Sr values, which are designated as “undefined” Abbreviations and symbols: Rb, rubidium; Sr, strontium; Zr, zirconium; La, lanthanum; Ce, cerium; ‰, per mil]

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