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Uranium/Thorium dating of ferricretes from mid- to late Pleistocene glacial sediments, western Tasmania, Australia. 500 ka precipitation record from southeastern Australia: evidence for interglacial relative aridity.
In 1907, the American chemist Bertram Boltwood demonstrated that he could determine the age of a rock containing uranium-238 and thereby proved to the scientific community that radioactive dating was a reliable method.
This method is not reliable for measuring the age of rocks less than 10 million years old because so little of the uranium will have decayed within that period of time.
This method is also very limited because uranium is not found in every old rock.
Although the half-life of rubidium-87 is even longer than uranium-238 (49 billion years or 10 times the age of the earth), it is useful because it can be found in almost all igneous rocks.
Perhaps the best method for dating rocks is the potassium-40/argon-40 method.