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.
Let's review. The Earth's mantle is the thickest layer of the planet and accounts for about 84% of the Earth's volume and 67% of its mass. It lies between the crust and the core. The Earth's mantle is never very far away from us; much closer than the Moon, for instance.