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Oceanic crust is significantly simpler than continental crust and generally can be divided in three layers. [8] According to mineral physics experiments, at lower mantle pressures, oceanic crust becomes denser than the surrounding mantle. [9] Layer 1 is on an average 0.4 km thick.
Continental crust is also less dense than oceanic crust, whose density is about 2.9 g/cm 3 (0.10 lb/cu in). At 25 to 70 km (16 to 43 mi) in thickness, continental crust is considerably thicker than oceanic crust, which has an average thickness of around 7 to 10 km (4.3 to 6.2 mi).
North China Craton – Continental crustal block in northeast China, Inner Mongolia, the Yellow Sea, and North Korea; Ossa-Morena plate; Piemont-Liguria plate – Former piece of oceanic crust that is seen as part of the Tethys Ocean; Proto-Alps terrane; Rhenohercynian plate – Fold belt of west and central Europe, formed during the Hercynian ...
The estimated average density of the continental crust is 2.835 g/cm 3, with density increasing with depth from an average of 2.66 g/cm 3 in the uppermost crust to 3.1 g/cm 3 at the base of the crust. [13] In contrast to the continental crust, the oceanic crust is composed predominantly of pillow lava and sheeted dikes with the composition of ...
Oceanic crust is denser than continental crust because it has less silicon and more of the heavier elements than continental crust. [11] [12] As a result of this density difference, oceanic crust generally lies below sea level, while continental crust buoyantly projects above sea level. Average oceanic lithosphere is typically 100 km (62 mi ...
The thin parts are the oceanic crust, which underlies the ocean basins (5–10 km) and is mafic-rich [9] (dense iron-magnesium silicate mineral or igneous rock). [10] The thicker crust is the continental crust, which is less dense [11] and is felsic-rich (igneous rocks rich in elements that form feldspar and quartz). [12]
The variation in composition within the Earth's crust is much greater than that of other terrestrial planets. Mars, Venus, Mercury and other planetary bodies have relatively quasi-uniform crusts unlike that of the Earth which contains both oceanic and continental plates. [1]
New oceanic lithosphere is constantly being produced at mid-ocean ridges and is recycled back to the mantle at subduction zones. As a result, oceanic lithosphere is much younger than continental lithosphere: the oldest oceanic lithosphere is about 170 million years old, while parts of the continental lithosphere are billions of years old. [12] [13]