What all is the Earth's crust made of?

Question

I need to know what the earths crust is made of for my homework. it is really IMPORTANT! it is d ue tomorrow.

Answer 1

The earth's crust varies in composition with depth and location on the earth, it is all made of different rocks.

If we ignore sedimentary and metamorphic rocks and concentrate on igneous we can deduce what the crust is made of.

Crust can be divided into continental (where continents are) and oceanic crust (where oceans are). The Continental crust is less dense and therefore more buoyant than the oceanic crust. Continental crust is composed of more felsic (feldspar/quartz rich) minerals. An example of a this would be granite.

Oceanic crust is much thinner than Continental crust but more dense it is made at mid ocean ridges. This is because it is composed of denser (mafic) minerals. The mafic minerals are more rich in metals. An example of a rock which makes up Continental crust is basalt or gabbro.

Answer 2

The earth's crust is about 1/2 oxygen, 1/4 silicon, after that aluminum and some other stuff. Or, if you just want a simple answer, it's made of oxygen.