The Rock Cycle.
Rocks are constantly moving and are part of a never-ending rock cycle. Rocks are never created or destroyed; they simply change from one rock type to another. The rocks that you see today are the same ones that existed when the dinosaurs roamed the earth.
What are Rocks?
Rocks are made up of one or more minerals. There are three types of rocks. These are igneous, sedimentary and metamorphic rocks.
What are the types of rocks?
• Igneous rocks are rocks that are formed when molten rock cools. Molten rock comes from the core of the Earth.
• Sedimentary rocks form as the result of pressure placed on sediments, such as dirt, dust or smaller rocks.
• Metamorphic rocks are formed when igneous or sedimentary rocks are exposed to intense heat or pressure.
What is the rock cycle?
The rock cycle occurs when rocks transform between the different types. The rock cycle occurs in the different layers of the Earth.
What are the four main layers of the Earth?
• The crust is the outermost layer of the Earth and is between four to 25 miles thick. It is made up of sand, dirt and rock.
• The mantle is the second outermost layer of the Earth. It is the thickest layer, at 1,750 miles thick. Many minerals in the mantle are hot enough to become liquefied.
• The outer core is the second innermost layer of the Earth. The outer core is made up of molten iron and is 1,425 miles thick.
• The inner core is the innermost layer of the Earth. Here, temperatures reach 7,000 degrees Fahrenheit. The inner core is also made up of molten iron and is 1,500 miles thick.
What is the rock cycle process?
The rock cycle begins in the core of the Earth. Eventually the molten iron will work its way to the cooler parts of the outer mantle. At this point, the iron cools enough to become igneous rocks. These rocks often form mountains and ocean beds.
Eventually, the igneous rocks of the mantle will work their way into the crust, often due to weathering. Weathering will break apart the igneous rocks into tiny pieces of dust or dirt and these pieces become sediment.
Once this sediment is exposed to pressure, sedimentary rocks will be created. When these sedimentary rocks are exposed to high heats or pressure, they turn into metamorphic rocks.
If these metamorphic rocks are exposed to extremely high heat, then they will melt, becoming the liquid part of the Earth's core again.
Tags: layer Earth, miles thick, igneous rocks, molten iron, rock cycle
