What are the two classes 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.
Can you name 2 igneous rocks?
These rocks include: andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff. Pictures and brief descriptions of some common igneous rock types are shown on this page. Dacite is a fine-grained, extrusive igneous rock that is usually light in color.
What are the two types of igneous rocks Class 7?
The main two categories of igneous rocks are known as extrusive and intrusive rocks.
What are the two types of igneous rock explain with example?
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.
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 intermediate igneous rocks?
Igneous Rocks by Composition Intermediate rocks are roughly even mixtures of felsic minerals (mainly plagioclase) and mafic minerals (mainly hornblende, pyroxene, and/or biotite). There is little or no quartz.
What is the classification of igneous rock?
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 igneous rocks Class 7?
Igneous rocks: Granite, basalt, obsidian and dolerite have been classified as igneous rocks. This is because they were formed due to the cooling and solidification of lava beneath or on the Earth’s surface. Sedimentary rocks: Sandstone, coal, gypsum and limestone have been classified as sedimentary rocks.
What are the basis for classification of igneous rocks?
What are the two types of igneous rocks quizlet?
When lava or magma cools and hardens, it forms igneous rocks. The two main categories are extrusive and intrusive.
How do you classify igneous rocks based on mineral abundance?
Classification By Mineral Abundance. 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 4 types 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 is the 713 classification diagram for igneous rocks?
Figure 7.13 is a diagram with the minerals from Bowen’s reaction series, and is used to decide which name to give an igneous rock. Figure 7.13 Classification diagram for igneous rocks.
What is the difference between felsic and intermediate igneous rocks?
To be more specific, felsic rocks typically have biotite and/or amphibole; intermediate rocks have amphibole and, in some cases, pyroxene; and mafic rocks have pyroxene and, in some cases, olivine. Figure 3.4.1 A simplified classification diagram for igneous rocks based on their mineral compositions.