Primordial elements
You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.
| This article needs additional references or sources for verification. Please help improve this article by adding reliable references. Unverifiable material may be challenged and removed. |
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 the half-life on the given atoms must be greater than about 108 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.
Some unstable isotopes which occur naturally (such as carbon-14, tritium, and plutonium-239) are not primordial, as they must be constantly regenerated by stellar radiation (in the case of carbon and tritium) or geochemical transmutation (in the case of plutonium).
Helium is unusual; most of it would have escaped Earth's gravitational pull as it was forming. Most helium is mined and comes as a result of radioactive decay in the core of the earth, so it is difficult to characterize helium as primordial.
In astrochemistry, primordial elements are chemical elements which were synthesized in the first round of nuclear synthesis after the big bang. These are believed to include only hydrogen, helium, lithium, and beryllium. To produce heavier atoms, stellar nuclear synthesis is required. For this reason it is known that the sun is not a first-generation star.
See also
Template:Geol-stubAcknowledgement and Attribution Regarding Sources of Content
Some of the initial content on this page may be incorporated in part from copyleft sources in the public domain including wikis such as Wikipedia and AskDrWiki. Drug information for patients came from the The National Library of Medicine. Infectious disease information may have come from the Centers for Disease Control (CDC). Differential Diagnoses are drawn from clinicians as well as an amalgamation of 3 sources: 1.The Disease Database; 2. Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:3; 3. Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:7 .
