Uranium-thorium dating
The uranium-thorium dating , also uranium-series dating or uranium-thorium investigation , is a special form of radiometric dating . It is based on the radioactive decay of uranium - isotopes that are in the decay of thorium ( 230 convert Th). While the starting material is water soluble, the end product is not. So z. B. as a compound dissolved in water 238 U and 235 U penetrate into caves and there are bound in the lime of the sintered deposits or stalagmites , which did not contain any uranium decay products at the time of their formation. The radioactive clock begins to run with the storage, and the age of the calcification can be determined by measuring the initial and decay isotopes. With this dating method, the age of samples up to 500,000 years old can be determined.