Ewing, Rodney C. Department of Earth and Planetary Sciences, University of New Mexico, Albuquerque, New Mexico.
- Links to Primary Literature
- Additional Readings
Minerals that contain uranium (U) or thorium (Th) as an essential component of their chemical composition. Examples are uraninite (UO2) or thorite (ThSiO4). There are radioactive minerals in which uranium and thorium substitute for ions of similar size and charge. There are approximately 200 minerals in which uranium or thorium are essential elements, although many of these phases are rare and poorly described. These minerals are important, as they are found in ores mined for uranium and thorium, most commonly uraninite and its fine-grained variety, pitchblende, for uranium. Thorite and thorogummite are the principal ore minerals of thorium. Minerals in which uranium and thorium occur in trace amounts, such as zircon (ZrSiO4), are important because of their use in geologic age dating. The isotope uranium-238 (238U) decays to lead-206 (206Pb); 235U decays to 207Pb; 232Th decays to 208Pb; thus, the ratios of the isotopes of uranium, thorium, and lead can be used to determine the ages of minerals that contain these elements. See also: Dating methods; Lead isotopes (geochemistry); Thorite
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Its dedicated editorial team is led by Sagan Award winner John Rennie. Contributors include more than 9000 highly qualified scientists and 39 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 17,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information