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.
Intrusive igneous rock is formed from solidified magma below the surface of the Earth. Intrusive rock exhibits a phaneritic texture, where the individual crystal grains are vi â¦ sible without magnification. Examples of intrusive igneous rocks are granite, diorite, and gabbro. Igneous rocks, which are formed from magma, are furtâ¦. 2  An Introduction to the Mineral Biotite Mica and its Role in Geology Biotite mica is a common rock-forming mineral. 3  It belongs to a large group of minerals that are found in igneous and metamorphic rocks.