The more lead the rock contains, the older it is. The long half-life of uranium-238 makes it possible to date only the oldest rocks. Also, the half-life of potassium-40 is only 1.3 billion years, so it can be used to date rocks as young as 50,000 years old.
How is uranium-238 used in geological dating?
Uranium-234–uranium-238 dating, method of age determination that makes use of the radioactive decay of uranium-238 to uranium-234; the method can be used for dating of sediments from either a marine or a playa lake environment.
Is uranium used to date rocks?
Uranium–lead dating method Uranium–lead radiometric dating involves using uranium-235 or uranium-238 to date a substances absolute age. This scheme has been refined to the point that the error margin in dates of rocks can be as low as less than two million years in two-and-a-half billion years.
Can you touch natural uranium?
Its relatively safe to handle. Its weakly radioactive and is primarily an alpha particle emitter. Alpha particles are very large so they cant really penetrate your outer layers of dead skin to damage living tissue. Just wash your hands afterward.