why continental crust has more thickness but less density?reasons

Expert Answers
trophyhunter1 eNotes educator| Certified Educator

The continental crust consists of a layer of metamorphic, igneous and sedimentary rock. It contains felsic or granitic rock. The oceanic crust, mainly contains mafic or basaltic rock. This dark colored rock is rich in iron and magnesium.  The density of the granitic rock of the continental crust is approximately 2.7 gm/cm3. The oceanic crust on the other hand, has a density of 2.9 g/cm3 which makes it more dense than the continental crust. The oceanic crust is a thinner layer than the continental crust--the oceanic crust is 3.3 miles in contrast to the continental which is 18.6 miles thick. There is evidence to support the fact that the continental crust is much older than the oceanic crust.

monakhan | Student
There are two main reasons: 1)The compositon of continetal crust is such that it has more thickness but the density is less. 2)The pressure inside the continental crust is high due to presence of water vapours.Actually it is the high pressure of water vapours due to which the density decreases and thickness increases.

Access hundreds of thousands of answers with a free trial.

Start Free Trial
Ask a Question