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Continental and oceanic crust are both less dense than mafic rocks. Continental crust is primarily composed of granitic materials, while oceanic crust is mainly basaltic, which is mafic in composition. However, basalt is denser than the average continental crust, making oceanic crust denser than continental crust but still less dense than pure mafic rocks. Therefore, in general, both types of crust are less dense than mafic materials.
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Which rock makes continental and oceanic crust?
The rock that makes up both continental and oceanic crust is called basalt. Basalt is a mafic extrusive igneous rock that forms when lava cools and solidifies rapidly at the Earth's surface. It is commonly found in oceanic crust, while continental crust is made up of a variety of rocks including basalt.
How do the two types of crust vary?
Their main differences are in thickness, composition, density and age.Oceanic crust is thinner (5-10 km thick) than continental crust (20-70 km thick).Oceanic crust is composed of minerals that have higher concentrations of iron and magnesium (Mafic minerals) than those of the continental crust (which is richer in aluminum and silica - Felsic minerals).The rocks that make up the oceanic crust are typically more dense (3300 kg/m3) than those that make up the continental crust (2700 kg/m3).Oceanic crust is as a rule much younger than continental crust; the oldest oceanic crust is rarely over 200 million years in age, whereas the continental crust can exceed 3 billion years in age.
What is crust of the geosphere?
== == The Crust--The outer skin of the planet is composed of igneous, metamorphic, and sedimentary rock. Continental Crust: Comprised predominately of rocks most resembling granite, the continental crust is relatively thick compared to the oceanic crust with a depth that ranges from 30 km to 50 km. The average specific gravity of continental crustal rock is 2.7. Oceanic Crust: At an average depth of 5 km to 10 km, the oceanic crust is thinner than the continental crust. Oceanic crustal rocks are composed mainly of the igneous rocks basalt, diabase, and gabbro, which are mafic in composition. The average specific gravity of oceanic crustal rock is 2.9.
When a continental plate and an oceanic plate collide why does the oceanic plate sink below the continental plate?
The oceanic plate is denser than the continental plate due to its composition of heavier mafic rock. This density difference causes the oceanic plate to sink below the continental plate in a process known as subduction.
Which rock is denser continental or oceanic rock?
The average continental rock is less dense than the average oceanic rock. This is why when an oceanic and continental plate collide, the continental plate does not get subducted. There are varyations within the continental plates however, with some rocks being muck more dense and some being much less dense than the average.
How does density of the oceanic crust differ from that of continental crust?
Oceanic crust is more dense than continental crust and is comprised of mainly mafic minerals (Mg, Fe), as opposed to continental crust, which is mainly felsic (Al and Si rich).
How does density of oceanic crust differ from that of continental crust?
Oceanic crust is more dense than continental crust and is comprised of mainly mafic minerals (Mg, Fe), as opposed to continental crust, which is mainly felsic (Al and Si rich).
How does the density of oceanic crust differ from that of continental crust?
Oceanic crust is denser than continental crust because it is primarily composed of basalt, which is a mafic rock with a higher density than the felsic rocks that make up continental crust. Additionally, oceanic crust is thinner and younger than continental crust, contributing to its higher density.
What is the difference in density in mafic rocks in relation to felsic rocks?
Mafic rocks, such as those found in the oceanic crust, are more dense than the felsic rocks found in the continental crust.
Is the oceanic crust felsic or mafic?
Oceanic crust is mafic.
Why does the oceanic crust go under the continental crust when they collide?
Oceanic crust is denser than continental crust because it is composed of mafic rocks like basalt, whereas continental crust is made of felsic rocks like granite. This density difference causes the oceanic crust to subduct under the less dense continental crust when they collide at convergent plate boundaries.
Characteristics of oceanic and continental crusts?
Oceanic crust is thinner, denser, and primarily composed of basaltic rock, while continental crust is thicker, less dense, and mainly consists of granitic rock. Oceanic crust is younger and continuously forming at mid-ocean ridges, whereas continental crust is older and more stable. Oceanic crust is also denser because it is made from more mafic, iron and magnesium-rich rocks.
Why is the main reason that oceanic crust is heavier than continental crust?
Oceanic crust is mafic in composition and continental crust is felsic in composition. Mafic minerals generally have a higher density than felsic minerals and therefore, the oceanic crust is heavier.
What accounts for the difference in density between oceanic crust and contenetial crust?
Continental crust is made of granite, and forms the continents and areas of shallow seabed close to their shores. It is less dense than the material of the mantle, which consists of mafic rock. Continental crust is then less-dense than oceanic crust, which, due to sea-floor spreading, is hardened mantle/lithosphere.
Why is oceanic crust subducted under continental crust?
Continental crust is less dense and cooler than oceanic crust and less dense and cooler than the asthenosphere, therefore instead of subducting, it is pushed upward in a collision between continents, or floats over a subducting oceanic crust.
Why does oceanic crust slide under continental crust during subduction?
The oceanic crust slides under the continental crust due to the differences in their densities. The continental crust is more felsic (contains more silica) which makes it lighter than the oceanic crust which is more mafic (containes more fe and mg). Because the process of subduction is very slow, gravitational forces have a stronger effect on the more dense oceanic crust, causing this crust to be pulled under the continental crust and down into the mantle.
What are the characteristics of the oceanic crust?
Oceanic crust is thinner and denser than continental crust, primarily composed of basaltic rock. It is typically younger due to the process of seafloor spreading, where new crust is formed at mid-ocean ridges and pushes older crust away. Oceanic crust is also more mafic in composition compared to continental crust.
