The continental crust is made largely of what rock?

1 Answer
Dec 4, 2015

Andesite (on average)


A while back, some cool geologists thought they would try to come up with an average composition of the continental crust. This was a mammoth task considering the continental crust is 40% of earths surface!

Despite this, they took a heap of samples, did some chemistry and averaged all the compositions to come up with a final composition, this composition was andesite. A rock named after the location where is was abundantly found - the Andes in South America.

But, the earths continental crust is made up of many many different types of rocks (mainly felsic rocks) and these rocks are also different from the top to the bottom of the crust. So it is tricky to come up with one answer but it is helpful to consider an 'average' composition, but don't think that this is the only rock type on Earth.