Question

1. Describe the most important diagnostic properties in igneous rocks.

Answer 1

1- The terrestrial lithosphere is composed almost of 80% by igneous rocks, they are also known as magmatic rocks and are formed at high temperatures due to magma solidification, they come from the superior mantle and terrestrial coast. Its texture is super resistant with significant hardness to obtain minerals and other derived materials. They can be divided into extrusive and intrusive.

2- Through experiments, Bowen has defined a sequence of mineral formation when a magma begins to cool. There are two types of magmatic differentiation defined by Bowen, the continuous series and the discontinuous series. In the continuous series the internal structure of the magma is not altered and all minerals have iron and magnesium, they are formed: aluminum, silica and sodium and calcium.

In the discontinuous series decreasing the temperature reacts the previously formed mineral with the existing liquid, and thus a new mineral with different internal structure and composition is formed. They are formed: olivine, pyroxena, amphibole and biotite.