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The increase in the Earth’s volume each year.


If the surface area of the Earth is 5.1 x 10^8 km2, and it increases its radius by 0.908 cm per year ( 9.08 X 10 ^ -6 km) , 4540 km3 of rock material are added each year.


This new material comprises predominantly of basalt which forms at mid-ocean ridges.


Basalt weighs 3011 kgs per m3 = 3.0 x 10^12 kg/km3


1.36 x 10^16 kg of basalt are produced each year


An estimate of the heat of formation of this quantity of basaltic rock


If we consider basalt is predominantly formed from silica, we know that silica has a molar mass of 60.8 gm/mol.


In 1.36 x 10^16 kg of basalt there are 1.36 x 10^16 / 0.060 mols


                                = 2.2 x 10 ^17 mol


The heat of Formation of silica is -910.9 kJ/mol


So the heat of formation in 2.2 x 10^17 mol is


                                      2.0 x 10^23 joules


                                      Or 0.2 Zettajoules


Or 1 million times the energy released in the Hiroshima nuclear blast.


So 0.2 Zettajoules of energy are given out in the exothermic reaction between silicon ions and oxygen ions as they combine. This keeps the mantle hot, it causes the high hydrostatic pressures of the mantle against the undersurfaces of the crust, or the extrusion of magma through fissures in the Earth’s crust.





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