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Continental and oceanic crust on the Earth's upper mantle. Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates.
The crustal dichotomy is the distinct contrast in composition and nature of the oceanic and continental plates, which together form the overall crust.The difference between continental and Oceanic crust.
The thickness of Earth's crust (km). The continental crust consists of various layers, with a bulk composition that is intermediate (SiO 2 wt% = 60.6). [5] The average density of the continental crust is about, 2.83 g/cm 3 (0.102 lb/cu in), [6] less dense than the ultramafic material that makes up the mantle, which has a density of around 3.3 g/cm 3 (0.12 lb/cu in).
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]
Continental crust – Layer of rock that forms the continents and continental shelves; Oceanic crust – Uppermost layer of the oceanic portion of a tectonic plate; Earth's mantle – A layer of silicate rock between Earth's crust and its outer core
The observed continental drift is a complicated relationship between the forces causing oceanic lithosphere to sink and the movements within Earth's mantle. Although there is a tendency to larger viscosity at greater depth, this relation is far from linear and shows layers with dramatically decreased viscosity, in particular in the upper mantle ...
The main features of passive margins lie underneath the external characters. Beneath passive margins the transition between the continental and oceanic crust is a broad transition known as transitional crust. The subsided continental crust is marked by normal faults that dip seaward. The faulted crust transitions into oceanic crust and may be ...
A continental margin is the outer edge of continental crust abutting oceanic crust under coastal waters. It is one of the three major zones of the ocean floor, the other two being deep-ocean basins and mid-ocean ridges. The continental margin consists of three different features: the continental rise, the continental slope, and the continental ...