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.
Earth's mantle is the thickest part of the planet and consists of very hot and plastic like solid rock. The mantle is divided into the lower and upper mantle, with the upper mantle making up 15.3 percent of the mantle crust mass and 10.3 percent of Earth's total mass. Learn more about Layers of the Earth