Iliac crest pain is not that common in the general population, but it is frequent in older individuals, runners (and athletes in general), lower back pain sufferersâ¦ But that doesn`t mean âregularâ people like you and me can`t experience it from time to time!
The mantle is composed of iron-magnesium silicates, and the crust is composed of roughly 5 percent iron. All together, iron makes up an estimated 35 percent of the Earth's mass. Oxygen. Oxygen, the second most abundant element on Earth, is found mainly in the crust.
The crust is the thinnest of the Earthâs three layers and the top part of the lithosphere. It is only about 8 kilometers (5 miles) thick under the oceans and 32 kilometers (20 miles) beneath continents.The rocks in the crust are primarily made of oxygen, silicon, aluminum and iron.ore About the Mantle. The crust is an important part of the lithosphere, but below it lies the other component: the top part of the upper mantle. This is denser than the crust. Like the crust, it contains rocks with large amounts of silicon and oxygen, but the mantle also has significant amounts of iron and magnesium.