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Rb/Sr geochronology in the Eastern Alps
Contributions to Mineralogy and Petrology, 1976New Rb/Sr data on mineral and whole rock samples from in and around the south-east corner of the Tauern Window are presented. Pennine orthogeneisses yield an Rb/Sr whole rock age of 279±9 m.y., while orthogneiss samples from the Altkristallin Sheet near Innerkrems, Carinthia, yield an age of 381±30 m.y. by the same technique.
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1979
The Rb-Sr method is based on the β-decay of 8 7Rb which decays to 8 7Sr with a half life of 48.8 × 109 years. This half-life corresponds to the recommended decay constant (Steiger and Jager, 1977) of 1.42 × 10−11 /y. In the last years two different decay constants have been used.: λ(8 7Rb) = 1.39 × 10−11/y and λ(8 7Rb) = 1.47 × 10−11/y.
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The Rb-Sr method is based on the β-decay of 8 7Rb which decays to 8 7Sr with a half life of 48.8 × 109 years. This half-life corresponds to the recommended decay constant (Steiger and Jager, 1977) of 1.42 × 10−11 /y. In the last years two different decay constants have been used.: λ(8 7Rb) = 1.39 × 10−11/y and λ(8 7Rb) = 1.47 × 10−11/y.
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Chemical weathering and Rb-Sr whole rock ages
Geochimica et Cosmochimica Acta, 1975Abstract Weathered whole rock samples of five lithic units from Maine, Virginia, North Carolina and South Carolina were analyzed to evaluate the effect of chemical weathering on the Rb-Sr ages of the original rocks. Major element and turbidity analyses, as well as standard X-ray diffraction and petrographic studies were made on selected samples.
Paul D. Fullagar, Paul C. Ragland
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Rb–Sr Geochronology (Igneous Rocks)
2013The preferential incorporation of Rb (following K) or Sr (following Ca) into different mineral structures, as well as their differing behaviors during closed system evolution of magmas by fractional crystallization, results in a wide range in Rb/Sr in mineral and whole rock compositions.
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Rb-Sr age measurements on various Swaziland granites
Journal of Geophysical Research, 1962Rb-Sr age measurements have been made on total-rock samples of eight granites from Swaziland, and the results obtained broadly conform with the stratigraphic classification of the granites into G5, G4, and G1. Three samples of the G5 granite gave ages of 2200±50 m.y., 2550±50 m.y., and 2880±340 m.y., respectively.
H. L. Allsopp +3 more
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Rb-Sr Dating of Illite Diagenesis: ABSTRACT
AAPG Bulletin, 1982In the Woodford Shale (Upper Devonian), apparent Rb-Sr ages decrease as clay grain size decreases, which in turn correlates with increasing abundance of diagenetic illite. Analyses of the fine-clay size fraction (< 0.2µ) from widely spaced wells in the Delaware basin of west Texas, plot on a single isochron indicating an age of 300 ± 4 m.y.
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Rb, Sr, Nd and Sm concentrations in quartz
Geochimica et Cosmochimica Acta, 1987The concentrations of Rb, Sr, Nd and Sm in quartz crystals from Crystal Peak, Colorado; Stewart Mine, California; Tomas Gonzaga, Minas Gerais, Brazil; and Coleman Mines, Arkansas, were determined by isotope dilution mass spectrometry. Concentrations ranged from: 1.17 to 177 ppb Rb; 3.26 to 1027 ppb Sr; 0.0159 to 0.48 ppb Sm; 0.127 to 2.81 ppb Nd.
Rossman, George R. +2 more
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Rb‐Sr data structure ‐ a possible cause for differences in Rb‐Sr whole‐rock and U‐Pb zircon ages
GFF, 1994Abstract Differences between U‐Pb zircon and Rb‐Sr whole‐rock ages are often interpreted to be due to later geologic disturbances such as low‐grade metamorphism and slow cooling. Yet, apparently contrasting ages can also be due to erroneous ages derived from non‐ideal systems.
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An Rb/Sr Age of the Småland Porphyries
Geologiska Föreningen i Stockholm Förhandlingar, 1972Abstract Rb/Sr whole-rock radiometric dating of 14 porphyries from Smaland, southeastern Sweden, yields an age of 1695 ± 20 million years (m. y.) (λ = 1.39 × 10−11 y.−1). The initial Sr87/Sr86 ratio is 0.7065 ± 0.0012. The relationship between the Smaland porphyries may be compared with that between the Dala porphyries, with respect both to relative ...
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