Radiogenic Heat of the Earth
Radiogenic Heat of the Earth
the heat given off when radioactive elements in the earth’s interior decay. A decisive role is played by the long-lived radioactive isotopes 40K, 232Th, 235U, and 238U, which have half-lives of 109–1010 years. There are no direct data on the content of potassium, thorium, and uranium deep within the earth. The amount of these elements in the earth is usually estimated according to the content of meteorites, based on the assumed similarity of the composition of meteorites to the composition of the earth’s mantle and core.