Igneous /Magmatic rocks- Part 02

1.Basic
     1.1.Volcanic or extrusive rock
     1.2.Plutonic or intrusive rock

2.Advanced
     2.1.Stages of the igneous or magmatic cycle

3.Expert
     3.1.Zircon to calculate the age of the earth

Today we are talking about highlighted topics

Advanced

Stages of the igneous or magmatic cycle

The stages of the igneous or magmatic cycle are as follows

1. Early magmatic phase (early crystallization) from the fiery hot magma

        Chromite

        Magnetite

        Titanium magnetite

2. Liquid magmatic phase (main crystallization) 1500-600 degrees °C

         Spinel

         Zircon

         Apatite

         Peridot

         Diamond

3. Pegmatite phase (rest crystallization) 700-400 degrees °C

The residual part of the magma, which is rich in fluxes, is known as the pegmatite stage. The melt becomes a watery solution as solidification proceeds. Because of this fluidity, the liquids can penetrate fissures and cracks in the surrounding rocks. Under the concentrated pressure and temperatures, individual crystals form that can measure several centimeters, and occasionally several meters! The prismatic crystals grow perpendicular to the walls of the vein. Pegmatite veins are some of the best examples of gemstone formation.

        Tourmaline

        Beryl

        Quartz

        Feldspar

        Zircon

        Apatite

        Brazilianite

        Graphite

        Muscovite

        Lepidolite

4. Pneumatolytic phase 500-300 degrees °C

Minerals formed in this phase form at lower temperatures and rising pressure. Superheated volatile components are involved. The most prominent of these components is water vapor, boron and fluorine gases. Under the influence of these vapors, other minerals are often formed in the contact zone of limestone.

         Topaz

         Euclase

         Vesuvianite

         Fluorite

         Cassiterite

         Sheelite

         Wolframite

5. Hydrothermal phase 400-500 degrees °C

This is a process associated with igneous activity that involves heated or super-heated water. Water at very high temperature and pressure is an exceedingly active substance, capable of breaking down silicates and dissolving many substances normally thought to be insoluble. This is the last stage of minerals that can be considered to be formed directly from magma.

         Gold

         Silver

         Emerald (Colombian)

         Beryl

         Quartz

         Barite

         Pyrite

         Dolomite

         Calcite