Question: How does the rate of radioactivity affect tectonic processes?

Hi zainab2000:
Radioactivity is important for plate tectonics as the heat emitted from radioactive isotopes contributes to the internal heat of the Earth. Now, the rate of decay of unstable isotopes like Uranium/Thorium is very slow (many billions of year). That means that isotopes like Uranium/Thorium that formed when the Earth formed are still decaying. One important aspect of radiogenic decay is that the rate of radioactive decay is constant and does no not change throughout the decay of the isotope. This is useful because we can use the know decay rate to figure out how old minerals are. But the constant decay rate of isotopes means that that the rate of decay does not affect the tectonic process. What really contributes to tectonics, is the heat emitted from radioactivity in the interior of the Earth. If there were no heat inside the planet, there would most probably be no plate tectonics.