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Volcanic Rocks (K–Ar and Ar–Ar)

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Encyclopedia of Scientific Dating Methods

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The K/Ar dating scheme, using the conventional K/Ar method, and the closely related 40Ar/39Ar dating technique, especially the latter, yield numerical ages on igneous rocks that are commonly precise to 1 % or better in the range 0.1 Ma or younger to much older ages (Lee 2014). The younger limit is dependent on detecting radiogenic argon above an atmospheric argon component mainly from the sample itself. The basis for these techniques is described by McDougall (2014) and Lee (2014). The means by which fossils in sedimentary sequences are assigned numerical ages by interpolation between dated volcanically derived beds is illustrated by an example from the hominin-bearing sequence in the Turkana area of East Africa.

Historically, the K/Ar dating method has been of importance in providing age information related to a variety of studies over at least the last five decades, including the delineation and calibration of the geomagnetic polarity time scale, one of the essential foundations for...

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Authors and Affiliations

  1. Research School of Earth Sciences, The Australian National University, Canberra, 2601, ACT, Australia

    Ian McDougall

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  1. Ian McDougall
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Correspondence to Ian McDougall .

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Editors and Affiliations

  1. School of Geography and Earth Sciences, McMaster University, Hamilton, Ontario, Canada

    W. Jack Rink

  2. Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada

    Jeroen Thompson

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McDougall, I. (2014). Volcanic Rocks (K–Ar and Ar–Ar). In: Rink, W., Thompson, J. (eds) Encyclopedia of Scientific Dating Methods. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-6326-5_265-1

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  • DOI: https://doi.org/10.1007/978-94-007-6326-5_265-1

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