EARTH SCIENCE
TECTONICS
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Oceanic
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Continental
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They always have the same density.
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None of the above
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Detailed explanation-1: -Continental crust is broadly granitic in composition and, with a density of about 2.7 grams per cubic cm, is somewhat lighter than oceanic crust, which is basaltic (i.e., richer in iron and magnesium than granite) in composition and has a density of about 2.9 to 3 grams per cubic cm.
Detailed explanation-2: -Oceanic crust is generally composed of dark-colored rocks called basalt and gabbro. It is thinner and denser than continental crust, which is made of light-colored rocks called andesite and granite. The low density of continental crust causes it to “float” high atop the viscous mantle, forming dry land.
Detailed explanation-3: -The crust is made up of solid rock but these rocks are not the same all over the world. Magma Page 2 the densest type of crust (3.0 g/cm³) and is made up of a metamorphic rock called basalt. Continental crust makes up the continents and rests on top of oceanic crust.
Detailed explanation-4: -Earth’s crust is generally divided into older, thicker continental crust and younger, denser oceanic crust. The dynamic geology of Earth’s crust is informed by plate tectonics.
Detailed explanation-5: -The average density of oceanic crust is 3.0 g/cm3, while continental crust has an average of 2.7 g/cm3.