As has already been described, igneous rocks are classified into four categories, based on either their chemistry or their mineral composition: felsic, intermediate, mafic, and ultramafic. The diagram in Figure 3.16 can be used to help classify igneous rocks by their mineral composition.
What are the two classification of igneous rocks?
The two main types of igneous rocks are plutonic rocks and volcanic rocks. Plutonic rocks are formed when magma cools and solidifies underground. Volcanic rocks are formed from lava that flows on the surface of the Earth and other planets and then cools and solidifies.
what is the classification of rocks? The three main types, or classes, of rock are sedimentary, metamorphic, and igneous and the differences among them have to do with how they are formed. Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material. Together, all these particles are called sediment.
how do you classify igneous rocks?
Igneous rocks may be simply classified according to their chemical/mineral composition as felsic, intermediate, mafic, and ultramafic, and by texture or grain size: intrusive rocks are course grained (all crystals are visible to the naked eye) while extrusive rocks may be fine-grained (microscopic crystals) or glass (
What are the 4 igneous rock compositions?
They include olivine, pyroxene, amphibole and biotite. The light-colored silicates include quartz, muscovite and feldspar. Solidification from magma produces great diversity in the mineral compositions which make up the rocks.
What is the other name of igneous rock?
Igneous rocks are also known by the names plutonic and volcanic rock. Plutonic rock is another name for intrusive igneous rock.
What is the texture 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 igneous rocks and are used in rock classification. There are six main types of textures; phaneritic, aphanitic, porphyritic, glassy, pyroclastic and pegmatitic.
What is basic igneous rock?
Basic rocks such as gabbro, dolerite and basalt are poor in silica and contain the minerals olivine, pyroxene, feldspar and/or quartz among others; they are also rich in the metals magnesium and iron and are often described as “mafic”. The intermediate rocks include diorite, microdiorite and andesite.
What are the properties of igneous rock?
Igneous rock, also known as volcanic rock, is formed by the cooling of magma or lava. This type of rock is classified by cooling time and the type of magma it is formed from. The properties of these rocks vary greatly, including their chemical composition, grain structure, texture and color.
What do you mean by igneous rock?
Igneous rock (derived from the Latin word ignis meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava.
What are the examples of igneous rocks?
Granite, gabbro, pegmatite, basalt, etc. are some of the examples of igneous rocks. There are two types of igneous rocks: intrusive rocks (Granite)and extrusive rocks (Basalt-Deccan Traps). Acid igneous rocks, such as granite, are less dense and are lighter in colour than basic rocks.
What are igneous rocks made of?
Magma that has come out to the surface is called lava. Lava cools off quicker on the surface than below. Rocks resulting from cooled-off lava include obsidian, lava rock, basalt or pumice. These are known as extrusive igneous rocks because they are formed outside of the crust.
How are igneous rocks formed step by step?
Rock Cycle Steps & Science Lesson Igneous rocks are formed when hot magma (melted rock) is rapidly cooled, either by hitting underground air pockets or by flowing from the mouth of a volcano as lava. Sedimentary rocks are formed by layers of sediment (dirt, rock particles, etc.)
How Igneous rock is formed?
In essence, igneous rocks are formed through the cooling and solidification of magma ( or lava). As hot, molten rock rises to the surface, it undergoes changes in temperature and pressure that cause it to cool, solidify, and crystallize.
Where can igneous rocks be found?
Where Igneous Rocks Are Found. The deep seafloor (the oceanic crust) is made almost entirely of basaltic rocks, with peridotite underneath in the mantle. Basalts are also erupted above the Earth’s great subduction zones, either in volcanic island arcs or along the edges of continents.