High Quality Content by WIKIPEDIA articles! In geochemistry, Primordial elements are chemical elements found on the earth that have existed in their current form since before the earth was formed, according to accepted stellar evolution theory. This means that there exist at least one isotope for a given element whose half-life must be greater than about 100 million years. All stable elements are primordial, as are some radioactive elements including thorium (due to isotope 232), and uranium. It has also been shown that plutonium is primordial, although just barely as its most stable isotope (plutonium-244) concentration in ores is nearly undetectable.

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