GEOLOGY

EARTH SCIENCE

TECTONICS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
what is the continental crust made of
A
metamofic and ignous purple rocks
B
cool volcanic substanses
C
sedimentary rocks, less dense
D
None of the above
Explanation: 

Detailed explanation-1: -The continental crust is composed of granitic rocks, which have even more silicon and aluminum than the basaltic oceanic crust and are less dense than basalt.

Detailed explanation-2: -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-3: -The thinner oceanic crust is normally a little more than four miles thick, while the thicker continental crust is often as much as 25 miles thick. Continental crust is also much less dense than its oceanic counterpart.

Detailed explanation-4: -Continental Crust Continental crust is mostly composed of different types of granites. Geologists often refer to the rocks of the continental crust as “sial.” Sial stands for silicate and aluminum, the most abundant minerals in continental crust.

Detailed explanation-5: -The crust is thickened by the compressive forces related to subduction or continental collision. The buoyancy of the crust forces it upwards, the forces of the collisional stress balanced by gravity and erosion. This forms a keel or mountain root beneath the mountain range, which is where the thickest crust is found.

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