Oceanic crustis dominated by mafic and ultramafic intrusive igneous rocks whereascontinental rocksare dominated by granitic (felsic) intrusive igneous rocks.The mantle, oceanic crust, and continental crust all
Density:With an average density of about 2.7 grams per cubic centimeter, the continental crust is less dense than oceanic crust, which is why it "floats" higher on the mantle. Age:Continental crust contains some of the oldest rocks on Earth, with portions dating back over 4 billion years. ...
In the continental crust, the maximum concentrations are on the order of 50 to 100 times the primitive-mantle values, and these are attained by the most highly incompatible elements Cs, Rb, Ba, and Th. In the average oceanic crust, the maximum concentrations are only about 10 times the ...
The continental crust is also less dense than oceanic crust, although it is considerably thicker. As a consequence of the density difference, when active margins of continental crust meet oceanic crust in subduction zones, the oceanic crust is typically subducted back into the mantle. Because of ...
The presence of continental crust is a signature of plate tectonics that distinguishes Earth from other planets. Because continental crust is made of lighter (granitoid) material than (basaltic) oceanic crust and its overall density is therefore less, the lithospheric segments that contain continental ...
Trench Island are Oceanic crust Continental crust Lithosphere Lithosphere Asthenosphere板块构造学说是20世纪最重要的科学成果之一,它科学地解释了地震、火山等地壳运动的机理.如图为某种类型的板块边界示意图.回答4-6题.以下地貌单元中,成因与图示机理相关的是( ) A. A. 东非大裂谷 B. B. 日本列岛 C. C....
Thin oceanic crust is formed by decompression melting of the upper mantle at mid-ocean ridges, but the origin of the thick and buoyant continental crust is enigmatic. Juvenile continental crust may form from magmas erupted above intra-oceanic subduction
Discover what type of crust is found under the continents. Learn the continental crust definition, oceanic crust vs. continental crust, and...
the different elevations ofcontinental crustandoceanic crust, the details of the original rift tectonics on passive continental margins, and the styles of subduction and accretion onconvergent margins. This tectonic frame has been modified, most profoundly on older margins, by the deposition of continen...
source of the oceanic crust. The continental crust has a mean age of about 2 × 109 years, roughly half the age of the Earth, whereas the oceanic crust is rapidly recycled into the mantle and has a mean life time of only about l0 s years or a fiftieth ...