Layers of the Earth

The Earth is complex in many ways. A study of the earth’s actual composition goes to show how truly complex it is. Not many people actually think about this, but the Earth is not a solid entity made up of the same mineral. In fact, the earth has three separate, distinct layers that are made up of different materials, serving different purposes.

The crust is the Earth’s outermost layer. It’s largely composed of types of rocks that are igneous or sedimentary. These are the same kinds of rocks that are produced after volcanic eruptions so they are common all over the world, wherever there are volcanoes. The crust is also where the minerals that are used to make silver jewelry and other metal items are found.

There are two kinds of crusts: the oceanic crust and the continental crust. The oceanic crust is composed of basalt, gabbro, and diabase minerals, measuring anywhere from 3 to 10 miles deep. The continental crust ranges from 20 to 30 miles thick. It is composed of granite or volcanic rocks. Granite, a type of igneous rock, is also commonly found all over the world, especially in quarries. The crust has temperatures that gets hotter the further down you go, ranging from 392°F to 752°F.

After the crust comes the mantle. This layer is about 1800 miles thick and makes up the largest volume of the earth’s entire volume, about 84%. The mantle itself actually has layers. Starting at 33 kilometers down, the upper mantle goes to a depth of 410 kilometers. Then, the transition zone starts at 410 kilometers deep and goes to 660km while the lower mantle starts at 660km and goes to 2918km.

The mantle is composed largely of garnet, spinel, olivine, peridotite, and eclogite. Garnet is typically found below ground in places like Russia, Europe, and South Africa. Olivine has actually been found on the Moon, the comet Wild 2, and Mars. Since it is closer to the core, the mantle’s temperature typically ranges between 932 °F at the uppermost boundary to 7,200 °F at the boundary at the core.

At the center of the Earth is the core. The core actually has two layers as well, the outer core and the inner core. Though nobody has actually seen this core, many experiments have been conducted to determine what properties the core most likely has. The inner core has a radius of 1220km and the outer core has a radius of 3400km. The inner core is believed to be composed of 80% iron, nickel, and possibly other materials, including two minerals that are also abundant on the earth’s surface. The core makes up about 15% of the Earth’s volume and it’s believed to be the reason that the Earth has a magnetic field. This magnetic field is caused by electric currents that can be found in the liquid outer core.

Structure Of The Earth
Earth's Interior
The Earth's Interior Structure

The Earth’s layers are very complex and there’s still a lot to be learned.