GEOLOGY

Detailed explanation-1: -The primary sources of thermal energy for mantle convection are three: (1) internal heating due to the decay of the radioactive isotopes of uranium, thorium, and potassium; (2) the long-term secular cooling of the earth; and (3) heat from the core.

Detailed explanation-2: -A major source of Earth’s heat is radioactivity, the energy released when the unstable atoms decay. The radioactive isotopes uranium-235 (235U), uranium-238 (238U), potassium-40 (40K), and thorium-232 (232Th) in Earth’s mantle are the primary source.

Detailed explanation-3: -The mantle within the earth’s surface flows due to convection currents. These currents are mainly caused by a very hot material present in the deepest part of the mantle, which rises upwards, then cools, sinks, again and again, repeating the same process of heating and rising.

Detailed explanation-4: -The heat that drives mantle convection comes from radioactive decay of elements within the core and mantle. This radioactive decay releases lots of energy and this energy causes those parts of the earth to become hot.

Detailed explanation-5: -The primary contributors to heat in the core are the decay of radioactive elements, leftover heat from planetary formation, and heat released as the liquid outer core solidifies near its boundary with the inner core.