What are the structure and texture of igneous rock?

What are the structure and texture of igneous rock?

The texture of igneous rocks depends on the composition of the magma and the conditions surrounding the magma’s cooling. The textures are different in intrusive, vein, and extrusive rocks. Intrusive rocks are characterized by a holocrystalline texture, in which all the rock material is crystallized.

What is the structure of rocks?

Rocks are composed primarily of grains of minerals, which are crystalline solids formed from atoms chemical bonded into an orderly structure. Some rocks also contain mineraloids, which are rigid, mineral-like substances, such as volcanic glass, that lacks crystalline structure.

What are the forms of igneous rocks explain structures and textures of igneous rocks?

Igneous textures include the rock textures occurring in igneous rocks. Igneous textures are used by geologists in determining the mode of origin of igneous rocks and are used in rock classification. There are six main types of textures; phaneritic, aphanitic, porphyritic, glassy, pyroclastic and pegmatitic.

What causes the structures of igneous rocks?

Igneous rocks form when magma (molten rock) cools and crystallizes, either at volcanoes on the surface of the Earth or while the melted rock is still inside the crust. All magma develops underground, in the lower crust or upper mantle, because of the intense heat there.

What is rock structure and formation?

Rock formations are usually the result of weathering and erosion sculpting the existing rock. A rock structure can be created in any rock type or combination: Igneous rocks are created when molten rock cools and solidifies, with or without crystallisation. They may be either plutonic bodies or volcanic extrusive.

What is the meaning of igneous?

1a : formed by solidification of magma igneous rock. b : relating to, resulting from, or suggestive of the intrusion or extrusion of magma or volcanic activity. 2 : of, relating to, or resembling fire : fiery.

What do igneous rock textures say about the rock that formed?

The igneous texture tells us how the magma cooled and solidified. Magma can solidify into igneous rock in several different ways, each way resulting in a different igneous texture. Magma may stay within the earth, far below ground level, and crystallize into plutonic igneous rock (also known as intrusive igneous rock).

How do vesicles form in igneous rocks?

As magma rises to the surface the pressure on it decreases. When the magma finally reaches the surface as lava and cools, the rock solidifies around the gas bubbles and traps them inside, preserving them as holes filled with gas called vesicles.

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.

What are the most common types of igneous rock textures?

Aphanitic. Describes the texture of fine-grained igneous rock in which different components are not distinguishable by the unaided eye.

Glassy.

Phaneritic.

Porphyritic.

What are the two classifications of igneous rocks?

Igneous rocks are of two types, intrusive (plutonic rocks) and extrusive (volcanic rocks). Intrusive igneous rocks are formed when the magma cools off slowly under the earth’s crust and hardens into rocks.

What processes create igneous rocks?

Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.

Can igneous rock be formed above or below ground?

We get Igneous rock when magma cools down and becomes a solid. The rock can form either above ground or below the surface . Above the ground – magma cools down quickly and we get rock such as Tuff and Basalt.