How old do you think it might be? Dating geological specimens involves an interdisciplinary approach using more than one dating method and cross-validating the results. Absolute dating methods include radiometric, luminescence and incremental dating. Relative dating methods fall under the science of stratigraphy. Radiometric Dating Radiometric dating is based on the knowledge that certain naturally occurring radioactive isotopes decay, or transform into a different element, at known rates. Radiometric dating includes carbon dating, illustrated used to date specimens up to about 75, years old, and 40K potassium Ar argon dating, which is used to date much older fossils. The older the sample, the smaller the ratio K-Ar. This is how we know that the Earth is about 4,5 billion years old. Luminescence Dating Geologists and archeologists use luminescence dating by observing photons, or light, emitted from minerals such as quartz, diamond, feldspar and calcite. As radiation from photons is stored in sediment layers, age since last exposure to sunlight can be calculated from this information.
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