Each decays through a series of relatively short-lived radioactive elements that each decay to a lighter element, finally ending up at lead. Zircon has a very high closure temperature, is resistant to mechanical weathering and is very chemically inert. With radiocarbon dating, we see that carbon decays to nitrogen and has a half-life of 5, years. This predictability allows the relative abundances of related nuclides to be used as a clock to measure the time from the incorporation of the original nuclides into a material to the present. Earth Science Rocks are made up of many individual crystals, and each crystal is usually made up of at least several different chemical elements such as iron, magnesium, silicon, etc.
Chronostratigraphy Geochronology Isotope geochemistry Law of superposition Luminescence dating Samarium—neodymium dating.
Creation Ministries International from the Journal of Creation 27 2: Cosmogenic Produced by bombardment of cosmic rays. By anyone's standards, 50 billion years is a long time. Eras Epochs.