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  2. K–Ar dating - Wikipedia

    en.wikipedia.org/wiki/K–Ar_dating

    Potassiumargon dating, abbreviated K–Ar dating, is a radiometric dating method used in geochronology and archaeology. It is based on measurement of the product of the radioactive decay of an isotope of potassium (K) into argon (Ar). Potassium is a common element found in many materials, such as feldspars, micas, clay minerals, tephra, and ...

  3. Absolute dating - Wikipedia

    en.wikipedia.org/wiki/Absolute_dating

    Other radiometric dating techniques are available for earlier periods. One of the most widely used is potassiumargon dating (K–Ar dating). Potassium-40 is a radioactive isotope of potassium that decays into argon-40. The half-life of potassium-40 is 1.3 billion years, far longer than that of carbon-14, allowing much older samples to be dated.

  4. Chronological dating - Wikipedia

    en.wikipedia.org/wiki/Chronological_dating

    Chronological dating, or simply dating, is the process of attributing to an object or event a date in the past, allowing such object or event to be located in a previously established chronology. This usually requires what is commonly known as a "dating method".

  5. Radiometric dating - Wikipedia

    en.wikipedia.org/wiki/Radiometric_dating

    Among the best-known techniques are radiocarbon dating, potassiumargon dating and uranium–lead dating. By allowing the establishment of geological timescales, it provides a significant source of information about the ages of fossils and the deduced rates of evolutionary change.

  6. Geochronology - Wikipedia

    en.wikipedia.org/wiki/Geochronology

    Potassiumargon dating and argonargon dating. These techniques date metamorphic, igneous and volcanic rocks. They are also used to date volcanic ash layers within or overlying paleoanthropologic sites. The younger limit of the argonargon method is a few thousand years. Electron spin resonance (ESR) dating

  7. Laetoli - Wikipedia

    en.wikipedia.org/wiki/Laetoli

    Two dating techniques were used to arrive at the approximate age of the beds that make up the ground layers at Laetoli: potassium-argon dating and analysis of stratigraphy. Based on these methods, the layers have been named as follows, starting with the deepest: Lower Laetolil Beds, Upper Laetolil Beds, Lower Ndolanya Beds, Upper Ndolanya Beds ...

  8. I asked a woman I'd known for 1 day to fly to Australia for ...

    www.aol.com/asked-someone-id-known-1-224137863.html

    "I’m often asked if I knew it would work out. The truth is I didn’t." Ash Jurberg shares the story of meeting his wife in an essay for TODAY.com.

  9. Argon–argon dating - Wikipedia

    en.wikipedia.org/wiki/Argonargon_dating

    Argonargon (or 40 Ar/ 39 Ar) dating is a radiometric dating method invented to supersede potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measurements, while the newer method requires only one rock fragment or mineral grain and uses a single measurement of argon isotopes.