GEO 103 Lecture Notes - Lecture 7: Chert, Clay Minerals, Mass Spectrometry
Document Summary
Half-life of radioactive isotope is time it takes for one half of the atoms in the original unstable parent isotope to decay to atoms of new more stable daughter isotopes. Half-life of specific radioactive isotope is constant and can be measured. Time of half-lives for different isotopes of different elements can vary from less than 1/billionth of a second to 49 billion years. These half-life times can vary quite a lot. Radioactive decay is a geometric process, not linear, so is a curved line on a graph of amount vs time. Disregarding how many atoms exists in the first place, the half-life is always the same. As magma cools and crystallizes, radioactive parent atoms separate from previously formed daughter atoms. Because they fit, some radioactive parents included in crystal structure of certain minerals in the cooling magma. In these crystals, only the specific atom exists.
