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Oceanic crust differs from continental crust in several ways: it is thinner, denser, younger, and of different chemical composition. Like continental crust, however, oceanic crust is destroyed in subduction zones. The lavas are generally of two types: pillow lavas and sheet flows.
What are the main features of crust?
The crust is made of solid rocks and minerals. Beneath the crust is the mantle, which is also mostly solid rocks and minerals, but punctuated by malleable areas of semi-solid magma. At the center of the Earth is a hot, dense metal core.
What are 3 characteristics of oceanic crust?
Not including a sedimentary cover of variable thickness and composition, the oceanic crust consists of three layers: (1) a relatively thin uppermost volcanic layer of basaltic lavas known as mid-ocean ridge basalts (MORB) erupted on the seafloor; (2) a thicker layer of more coarsely crystalline, intrusive basaltic Jul 18, 2018.
What are the characteristics of oceanic crust and continental crust?
It is the solid rock layer upon which we live. It is either continental or oceanic. Continental crust is typically 30-50 km thick, whilst oceanic crust is only 5-10 km thick. Oceanic crust is denser, can be subducted and is constantly being destroyed and replaced at plate boundaries.
What are the four features of crust?
In geology, a crust is the outermost layer of a planet. The crust of the Earth is composed of a great variety of igneous, metamorphic, and sedimentary rocks. The crust is underlain by the mantle. The upper part of the mantle is composed mostly of peridotite, a rock denser than rocks common in the overlying crust.
What are the two features of crust?
Summary Oceanic crust is thinner and denser than continental crust. Oceanic crust is more mafic, continental crust is more felsic. Crust is very thin relative to Earth’s radius.
What is an example of oceanic crust?
An example of this is the Gakkel Ridge under the Arctic Ocean. Thicker than average crust is found above plumes as the mantle is hotter and hence it crosses the solidus and melts at a greater depth, creating more melt and a thicker crust. An example of this is Iceland which has crust of thickness ~20 km.
What are the similarities and differences between oceanic crust and continental crust?
Continental crust is low in density whereas oceanic crust has a higher density. Continental crust is thicker, on the contrary, the oceanic crust is thinner. Continental crust floats on magma freely but oceanic crust floats on magma scarcely. Continental crust cannot recycle whereas oceanic crust can recycle it.
What are 3 differences between continental crust and oceanic crust?
The oceanic crust is mainly made out of dark basalt rocks that are rich in minerals and substances like silicon and magnesium. By contrast, the continental crust is made up of light-colored granite rocks full of substances like oxygen and silicon. The continental crust is older than the oceanic crust.
Why continental crust is thicker than oceanic crust?
The continental crust is also less dense than oceanic crust, although it is considerably thicker. Because of its relative low density, continental crust is only rarely subducted or recycled back into the mantle (for instance, where continental crustal blocks collide and over thicken, causing deep melting).
What are 5 facts about the crust?
Interesting Facts about the Earths Crust The crust is deepest in mountainous areas. The continental and oceanic crusts are bonded to the mantle, which we spoke about earlier, and this forms a layer called the lithosphere. Beneath the lithosphere, there is a hotter part of the mantle that is always moving.
What is the importance of the crust?
The crust is a thin but important zone where dry, hot rock from the deep Earth reacts with the water and oxygen of the surface, making new kinds of minerals and rocks. It’s also where plate-tectonic activity mixes and scrambles these new rocks and injects them with chemically active fluids.
What are the main features of crust and core?
Earth has three layers: the crust, the mantle, and the core. The crust is made of solid rocks and minerals. Beneath the crust is the mantle, which is also mostly solid rocks and minerals, but punctuated by malleable areas of semi-solid magma. At the center of the Earth is a hot, dense metal core.
How thick is Earth’s crust?
Earth’s crust is 5 to 70 km thick. Continental crust makes up the land on Earth, it is thicker (35 – 70 km), less dense and mostly made up of the rock granite. Oceanic crust makes up most of the ocean, it is thinner (5 – 7 km), denser and mostly made up of the rock basalt.
Why is it important to distinguish the two types of crust?
Explanation: The thin oceanic crust is composed of primarily of basalt, and the thicker continental crust is composed primarily of granite. The low density of the thick continental crust allows it to “float” in high relief on the much higher density mantlebelow.
What is Earth’s crust composed of?
From mud and clay to diamonds and coal, Earth’s crust is composed of igneous, metamorphic, and sedimentary rocks. The most abundant rocks in the crust are igneous, which are formed by the cooling of magma.Vocabulary. Term Part of Speech Definition molten adjective solid material turned to liquid by heat.
What is the physical properties of the earth’s crust?
Crust and Lithosphere Earth’s outer surface is its crust; a cold, thin, brittle outer shell made of rock. The crust is very thin, relative to the radius of the planet.
What are the four main layers of oceanic crust?
The oceanic crust, on the basis of seismological studies of the seafloor, dredge hauls, drilling, and studies of ophiolites on land, is layered consisting of an upper sedimentary layer, a middle basaltic volcanic layer, and a lower third layer consisting of gabbroic plutonic rocks.
What causes the sinking of the oceanic crust?
As our new crust slowly drifts at finger-nail speed (5 cm/yr) away from the ridge, it cools and grows denser, causing the sea-bed to sink. Sediment builds up on top. After 50Ma (million years) our crust is denser than the underlying mantle.
Why is oceanic crust denser?
In the theory of tectonic plates, at a convergent boundary between a continental plate and an oceanic plate, the denser plate usually subducts underneath the less dense plate. It is well known that oceanic plates subduct under continental plates, and therefore oceanic plates are more dense than continental plates.
