EPSC 201 Lecture Notes - Thymine, Boiling Point, Vehicle Emissions Control
11 Mar 2013
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Document Summary
Radiometric dating is based on the decay of unstable isotopes. Uranium is unstable and will de- cay at a constant rate. The key is that they decay by emitting alpha radiation, which consisted of two protons and two neutrons. If there are a large number of uranium atoms in the sample, we can measure the constant decay rate to determine how old the rock is. If we know the rate of decay, concentration of uranium and lead present, we can determine how old the rock sample. Only trace amounts of uranium (ppm) need to be present for this to be applicable. In reality, uranium breaks down into many different atoms long its path to lead. So we can measure all the inter- mediates to help determine the original concentration of uranium, and therefore the age of the rock. Natural lead has a mass of 207, which is different then radioactively produced lead.
