Igneous lithology

Igneous and metamorphic rocks comprise approximately 25% of the rocks of the earth’s crust, and their distribution is about 95% in the interior of the earth.

Magma: The molten and hot material that is formed from the melting of rocks inside the earth and is composed of various silicate minerals, water vapor, carbon dioxide and other gases.

Igneous rocks are usually divided into 3 groups based on spatial relationships or the average size of grains and crystals as described below.

1. Internal (Plutonic): They crystallize deep in the earth. The average size of the crystals is < 5 mm (coarse grain) or between 1 and 5 mm (medium grain).
2. Semi-deep (Hypabyssal): crystallized at a shallow depth and the average size of its crystals reaches 0.5 to 1.
3. Volcanic: These rocks are formed by the eruption of molten materials on the earth’s surface, and the average size of their crystals is >0.5 mm.

Important elements of igneous rocks:

• • When an igneous rock is chemically decomposed, this process is called Norm.
• It is calculated as a result of decomposition of important oxides Al, Mg, K, Na, Fe, Ca, Ti, Si.
• According to these elements and their constituent oxides, approximately 48% of the rocks of the earth’s crust are composed of oxygen, 27% of silicon and 8% of aluminum, and the rest of the elements are present in a smaller proportion in the rocks.

Igneous or pyroclastic rocks:

They are sedimentary-igneous rocks: (when solid volcanic materials rise from the earth and lose their heat in the marine environment at the same time and settle in the water environment, which are strengthened by Si cement and get pyroclastic texture).

Migmatite:

There are rocks between metamorphic and igneous: (granite magma injection in schist rocks is called).

Comagmatic rocks:

Its mineralogy and magma type are the same, but the depth of their formation (and consequently their texture) is different.

The division of magma based on the number of gases:

1. Hypomagma: contains a lot of gas
2. Pyromagma: full of gas and foam, with released gases without leaving the magma
3. Epimagma: poor in gas

Division of magma types:

1. Acidic magma: A: high quartz 20, B: thick with high viscosity, C: light and low specific gravity with light color, D: more water than alkaline magma, E: less deep formation
2. Playful magma: A: low quartz B: high specific gravity, C: dilute magma, D: low water, E: greater depth, F: dark color of rocks

Forms of igneous intrusive masses:

A) inclined or parallel masses

1. Flood: a basalt mass on the slope
2. Lacolith: mushroom-shaped infiltrating mass
3. Lupolite: concave intrusive mass
4. Bismalite: a type of laculite whose upper part is flat.
5. Facolite: injected masses in folds, anticlines and transgressions

B) uneven sloping or intersecting masses

1. Dike: crossed acidic mass
2. Batholith: masses larger than 100 square kilometers
3. Stock or Bes: masses smaller than 100 square kilometers

Types of textures of igneous rocks:

Aphantic: fine-grained (like slate)P

hanritic: coarse-grained (like schist)

texture: shape and size of grains:

Size of crystals:

• Coarse crystals: phenocryst or phenocryst
• Small crystals: microlite

Shape of crystals:

• Idiomorphic texture: shaped (lamprophyre)
• Idiomorphic hip texture: semi-shaped (granitic)
• Xenomorphic texture: Bishkel (aplite)

Internal igneous tissues:

Granular or granular or large grain or phanritic: It is specific to internals.

Lamprophyric texture: shaped crystals in lamprophyre

Aplitic texture: biskeletal crystals, sugar texture

Idiomorphic hip texture: common texture of granites, granitic

 Graphics or Graphir or Granofir:

Cuneiform growth of quartz in orthoclase F

Coarse grain that mostly contains Qtz + alkaline feldspar (Mic + Ort).

• Pegmatite: the cause is coarse water and volatile substances.
• Ophthalmology: Plg crystal can be seen inside Px (diabases)
• Subphytic: the length of Plg is greater than the diameter of Px.
• Diabasic: coarse grain that has saturated the space between Plg and Px with chlorite.
• Chalitic dynamics: encirclement of small crystals by large crystals.

Sericitization of feldspars and chloritization of grones is not kiloblastic poei.

Delerite: It is the same as diabasic, but it does not contain chlorite (Chl).

• Intergranular: plagioclase in different directions and in the space between them: Ol + Px
• Sieve: It belongs to superbasics where olivine has turned into serpentine.