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 mantle is the thick layer of hot, solid rock between the Earth's crust and the molten iron core. It makes up the bulk of the Earth, accounting for two-thirds of the planet's mass. The mantle starts about 30 kilometers down and is about 2900 kilometers thick. Let's take a look at six different aspects of the mantle.