So we expect that the description of the velocities of molecules in a gas will in fact be the most probable distribution, since we are dealing with particle numbers in the range of Avogadro's number. But this most probable distribution (the Maxwell-Boltzmann distribution) is subject to constraints, namely that the number of particles is constant and that the total energy is constant (conservation of energy).
The oldest rocks are metamorphic gneisses which are to be found on Inishtrahull, several miles off Malin Head in Co. Donegal, and elsewhere in the north-west. They originally formed as igneous rocks 1750-1780 million years ago.
igneous = fire rocks. igneous rock (made from hot, melted rock) Igneous rocks form when melted rock, or magma cools and hardens. Sometimes the igneous rocks form in the ground (intrusive igneous rocks), and sometimes they form outside of the ground (extrusive igneous rocks).