What is igneous?

What Does igneous Mean

Igneous is a term derived from the Latin word igneus . The concept is used to name what is linked to fire .

For example: “The firefighters were alerted at dawn to the existence of an igneous source in the middle of the forest” , “The igneous unit destroyed several homes and left three people injured” , “The explosion generated an igneous process that could only be suffocated several hours later ” .
In the field of geology , the rock that arises from the solidification of magma found inside the planet Earth is classified as igneous . Igneous rocks are produced when this molten matter cools and thus solidifies.

According to the way in which the cooling takes place, it is possible to differentiate between different types of igneous rocks. When said cooling is generated on the surface and quickly, it is called volcanic rocks , also called extrusive or effusive . In this case, which occurs when a volcano erupts, the rock crystals cannot be seen with the naked eye.
If, on the other hand, the cooling process is underground and develops slowly, igneous rocks are called intrusive or plutonic rocks and have large crystals .
Most igneous rocks are plutonic, like granite , diorite, and tonalite . Basalt , obsidian and rhyolite appear among volcanic igneous rocks .
It is estimated that about 95% of the upper sector of the earth's crust corresponds to igneous rocks. Over them an extensive layer of metamorphic rocks and sedimentary rocks is distributed .
The importance of igneous rocks for geology is considerable, and this is due to the following characteristics:
* Between its minerals and its global chemistry, they provide a series of data about the composition of the Earth's mantle (an inner layer from which the magma that gives rise to igneous rocks comes) and the pressure conditions and temperature that They reign at the moment in which the rock is formed or the previous one, the one that must have melted;
* The absolute age of igneous rocks can be ascertained through various radiometric dating systems , a procedure that can also be applied to organic and mineral remains. In this way it is possible to compare them with adjacent geological strata and establish a temporal sequence of the different events;
* in general, its features correspond to those of a particular tectonic environment , and this leads to the reconstitution of tectonic events;

* In certain well-defined cases, igneous rocks contain mineral deposits of great importance, such as uranium, tin and tungsten, which are usually associated with platinum, chromium and granites.
When classifying igneous rocks, one of the variables to take into account is their texture , which helps us to establish the description of their general appearance. While science acknowledges more, there are six fundamental textures:
* vitreous : they arise during certain volcanic eruptions after the molten rock cools rapidly in the atmosphere;
* aphanitic : it is also called fine-grained and is characterized by having very small crystals that make it difficult to distinguish its minerals with the naked eye;
* Phaneritic : for its formation it is necessary for the magma to cool slowly and deeply;
* Porphyritic : its crystals are large and are embedded in a paste of other smaller ones;
* Pegmatitic : the grain of these igneous rocks is very thick and the crystals that form it exceed one centimeter in diameter;
* Pyroclastic : they look like sedimentary rocks and are not made up of crystals.

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