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Unformatted text preview: Absolute Time Radiometric Dating: the source of the dates on the Geologic Time Scale Radiometric Dating Actually a simple technique. Only two measurements are needed: 1. The parent:daughter ratio measured with a mass spectrometer. 2. The decay constant measured by a scintillometer. Basis of the Technique 5DGLRDFWLYH HOHPHQWV GHFD\ 'HFD\ RFFXUV DV DQ element changes to another element, e.g. uranium to lead. The parent element is radioactive, the daughter element is stable. The decay rate is constant. What is Radioactivity? Radioactivity occurs when certain elements literally fall apart. Usually protons and neutrons are emitted by the nucleus. Sometimes an electron is emitted by the nucleus, which changes a neutron to a proton. Sometimes an electron is captured. What causes radioactivity? Carbon-14 is produced by cosmic ray bombardment of Nitrogen-14 in the atmosphere. All other radioactive elements were produced by supernova explosions before our solar system formed....
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- Fall '11
- Geologic Time Scale