A dating method for minerals based on the measurment of the ratio of radioactive potassium to radioactive argon. Radiocative potassium decays to form radioactive argon at a known rate. Argon is rare since it can readily escape to the atmosphere. Thus, its presence in a freshly opened stones is assumed to be due to the decay of potassium. The age of meteorites and volcanic stones are measured by this method.
Sources Checked for Data in Record
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
- Encyclopedia Britannica, http://www.britannica.com Comment: "potassium-argon dating." Encyclopædia Britannica. 2004. Encyclopædia Britannica Premium Service. 9 Nov. 2004 .