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potassium-argon dating |
Also found in: Dictionary/thesaurus, Wikipedia, Hutchinson | 0.17 sec. |
potassium-argon datingMethod for determining the age of igneous rocks based on the amount of argon-40 in the rock. Radioactive potassium-40 decays to argon-40 with a half-life of about 1.3 billion years, making this method useful for dating rocks that are billions of years old. A more sophisticated method, called argon-argon dating, provides a more accurate estimate of the original potassium-40 content by means of the ratio of argon-40 to argon-39 in the rock, thus yielding a more accurate age determination. See also dating. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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| Geophysicist Michael McWilliams of Stanford University dated the Brunhes-Matuyama transition at 780,000 years ago using the argon-argon technique, a variation of the standard potassium-argon dating method. While the most frequently quoted age for the traps falls around 60 million to 65 million years old, he says, other estimates, determined primarily from potassium-argon dating, range from 80 million to 30 million years old. Potassium-argon dating of the volcanic rocks puts the islands' ages between about 1 million (western islands) and 4 million (eastern islands) years. |
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