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Is continental and oceanic crust less or more dense than mafic?
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Is the highest density rock mainly found in the continental crust?
No, the highest density rock is found in the oceanic crust. This is commonly enriched in higher density elements such as magnesium and iron (hence the rocks are described as Mafic) as opposed to the Felsic rocks of the continental crust which have higher proportions of the less dense elements such as silicon and oxygen.
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.
What is the type of crust formed on the ocean floor?
Oceanic crust, formed mostly of mafic rocks, or sima, is found on the ocean floor.
What does the outter most layer of the earth consist of?
The thin, solid, outermost layer of the Earth is officially known as the crust.
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 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).
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.
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.
Is the oceanic crust felsic or mafic?
Oceanic crust is mafic.
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.
How does the rock under the continents differ from rock under the oceans?
The rock of the continental crust is mostly granitic in composition, meaning it is a high silicate intrusive igneous rock. The rock of the oceanic crust is basaltic in origin, meaning it is lower in silica and higher in heavier elements like iron and magnesium and is classified as a mafic igneous rock. Oceanic crust is therefore more dense than continental crust.
What is the ocean's crust made up of?
The oceanic crust is made up of mafic rocks which is rich in magnesium and iron. These rocks are also referred to as sima. The oceanic crust is similar to the continental crust, except it is thinner yet denser.
Why does one plate sink beneath another at a subduction boundary?
This is because of the differing densities of the two types of plate. Oceanic plates are composed of mafic rocks which have higher concentrations of iron and magnesium than the silica and aluminum rich rocks of the crustal plates. This concentration of iron and magnesium makes the oceanic crust more dense than the continental crust and so the oceanic crust tends to be forced under the continental crust at a subduction zone.
