What are the classification of igneous rocks?

Igneous rocks can be divided into four categories based on their chemical composition: felsic, intermediate, mafic, and ultramafic. The diagram of Bowen’s reaction series (Figure 7.6) shows that differences in chemical composition correspond to differences in the types of minerals within an igneous rock.

Which are used to classify plutons?

What are plutons and how are they classified? Plutons are intrusive igneous rock bodies. They are classified by size, shape, and relationship to the surrounding rock.

What is Iugs classification?

In order to create a sustainable classification of igneous rocks which all geologists might use, an international body was set up by the IUGS: the IUGS Subcommission on the Systematics of Igneous Rocks. The nomenclature for these classifications necessitates only 297 rock names out of the c. 1500 that exist.

How do you plot a QAPF diagram?

Using QAPF diagram Each component is represented by the corners of the equilateral triangle, the length of whose sides are divided into 100 equal parts. Any composition plotting at a corner, therefore, has a mode of 100 percent of the corresponding component.

What are the 2 basic classifications of igneous rocks?

The two main categories of igneous rocks are extrusive and intrusive. Extrusive rocks are formed on the surface of the Earth from lava, which is magma that has emerged from underground. Intrusive rocks are formed from magma that cools and solidifies within the crust of the planet.

How are plutonic rocks classified?

Igneous rocks may be divided into two categories. Intrusive or plutonic rocks crystallize from magma beneath the earth’s surface. Extrusive or volcanic rocks crystallize from lava at the earth’s surface. In addition to texture, igneous rocks may are classified according to their chemical composition.

How many types of plutons are there?

The most common rock types in plutons are granite, granodiorite, tonalite, monzonite, and quartz diorite. Generally light colored, coarse-grained plutons of these compositions are referred to as granitoids. The term originated from Pluto, the classical god of the underworld.

How do you do Iugs classification?

The principles are: (1) use descriptive attributes; (2) use actual properties; (3) ensure suitability for all geologists; (4) use current terminology; (5) define boundaries of rock species; (6) keep it simple to apply; (7) follow natural relations; (8) use modal mineralogy; (9) if mode not feasible, use chemistry; (10) …

What does QAPF stand for in mineral classification?

The acronym, QAPF, stands for “Quartz, Alkali feldspar, Plagioclase, Feldspathoid (Foid)”. These are the mineral groups used for classification in QAPF diagram. Q, A, P and F percentages are normalized (recalculated so that their sum is 100%).

What is the purpose of the QAPF diagram?

The QAPF and related diagrams are intended for classification of rocks in the field, or preliminary classification with modal proportions as seen in the optical microscope. They are not designed with the chemical composition of the rocks in the mind. Furthermore, these diagrams are merely descriptive and not genetic.

When to use QAPF diagram for volcanic rocks?

QAPF diagrams are not used to classify pyroclastic rocks or volcanic rocks if modal mineralogical composition is not determined, instead the TAS classification (Total-Alkali-Silica) is used. TAS is also used if volcanic rock contains volcanic glass (such as obsidian ).

How is the QAP ternary diagram used to classify rocks?

The QAP ternary diagram is used to classify igneous rocks with visible mineral grains (phaneritic texture) from their feldspar and quartz content. In plutonic rocks, all of the minerals are crystallized into visible grains.