Rocks Page: Igneous, Sedimentary, Metamorphic Rocks
by Owen Borville
January 30, 2021
Learning, Geology, Chemistry, Science
Rocks can be divided into three main groups: igneous, sedimentary, and metamorphic. Rocks can contain one or more mineral types.
Igneous rocks form either inside the earth or on the Earth's surface. Rocks that form on the surface of the Earth are called extrusive or volcanic rocks. These rocks form when hot, molten, liquid magma travels from inside the earth upward and is released from inside the Earth onto the Earth's surface and cools and hardens or solidifies into rock. When magma reaches the surface, it is termed lava.
The Most Common Volcanic Rock is Basalt, which covers most of the ocean floors on Earth. Basalt rock is rich in iron and magnesium, as it comes from inside the earth. The other main types of volcanic rock are andesite and rhyolite, which are lower in iron and magnesium content and richer in silica content. This larger silica content causes the formation of taller volcanic peaks and explosive volcanic eruptions. Basalt-rich magma produces flat, wide volcanic shapes on the Earth's surface because of its lower silica content. High silica content produces "viscosity," or thicker, sticky, less fluid magma. Dacite, obsidian, scoria, pumice, and pyroclastic rocks are types of volcanic rocks.
Rocks That Form Inside the Earth Are Called Intrusive Igneous Rocks. The most common intrusive igneous rock is granite, which forms large domes inside the earth near the surface and covering many square miles of land which causes overlying sedimentary rock layers to be uplifted.
The Rapid Cooling of Granite
Sedimentary Rocks Form from the Weathering and Erosion of other rocks, including igneous and sedimentary rocks. Water erosion, wind erosion, freezing, and thawing can form sedimentary rocks from mechanical erosion. Sedimentary rocks can also form from the cementation of sediment. Sedimentary rocks can also form from chemical alteration processes, such as those that produce clay-rich rocks. In addition, minerals can precipitate from liquids to form sedimentary rocks in layers.
Metamorphic Rocks form from Intense Heat and Pressure from Hot, Mineral Rich Fluids and Magma inside the earth, which causes rock to be altered physically and chemically from their original state. Metamorphic rocks can form on contact at a particular location with surrounding rock at the smaller scale, or can form in larger amounts and areas, called regional and dynamic metamorphism.
by Owen Borville
January 30, 2021
Learning, Geology, Chemistry, Science
Rocks can be divided into three main groups: igneous, sedimentary, and metamorphic. Rocks can contain one or more mineral types.
Igneous rocks form either inside the earth or on the Earth's surface. Rocks that form on the surface of the Earth are called extrusive or volcanic rocks. These rocks form when hot, molten, liquid magma travels from inside the earth upward and is released from inside the Earth onto the Earth's surface and cools and hardens or solidifies into rock. When magma reaches the surface, it is termed lava.
The Most Common Volcanic Rock is Basalt, which covers most of the ocean floors on Earth. Basalt rock is rich in iron and magnesium, as it comes from inside the earth. The other main types of volcanic rock are andesite and rhyolite, which are lower in iron and magnesium content and richer in silica content. This larger silica content causes the formation of taller volcanic peaks and explosive volcanic eruptions. Basalt-rich magma produces flat, wide volcanic shapes on the Earth's surface because of its lower silica content. High silica content produces "viscosity," or thicker, sticky, less fluid magma. Dacite, obsidian, scoria, pumice, and pyroclastic rocks are types of volcanic rocks.
Rocks That Form Inside the Earth Are Called Intrusive Igneous Rocks. The most common intrusive igneous rock is granite, which forms large domes inside the earth near the surface and covering many square miles of land which causes overlying sedimentary rock layers to be uplifted.
The Rapid Cooling of Granite
Sedimentary Rocks Form from the Weathering and Erosion of other rocks, including igneous and sedimentary rocks. Water erosion, wind erosion, freezing, and thawing can form sedimentary rocks from mechanical erosion. Sedimentary rocks can also form from the cementation of sediment. Sedimentary rocks can also form from chemical alteration processes, such as those that produce clay-rich rocks. In addition, minerals can precipitate from liquids to form sedimentary rocks in layers.
Metamorphic Rocks form from Intense Heat and Pressure from Hot, Mineral Rich Fluids and Magma inside the earth, which causes rock to be altered physically and chemically from their original state. Metamorphic rocks can form on contact at a particular location with surrounding rock at the smaller scale, or can form in larger amounts and areas, called regional and dynamic metamorphism.