Updated Notes for Chapter 1 Earth’s Layers
Igneous Rocks – Rocks form when magma, or molten rock, cools either deep in the earth or near its surface.
Metamorphic Rocks – Rocks form when sedimentary or igneous rocks are changed due to extreme heat and pressure.
Sedimentary Rocks – Rocks form from small pieces of broken rock and debris that get compacted and cemented together.
Igneous and Metamorphic Rocks – form a solid layer of the crust known as bedrock.
The 3 Main layers of the earth are: Crust, mantle and core. The core has two parts, the outer core which is molten (liquid) and the inner core which is solid (mostly iron and nickel).
The Crust is the thinner layer; the Mantle is the thickest layer.
The Continental crust makes up the earth’s landmasses and is made up mostly of granite. The Oceanic crust makes up the ocean floors and is made up of mostly basalt. Basalt is denser because it contains more iron. Oceanic crust is denser than continental crust.
Much of what we know about the earth’s interior comes from studying meteorites and how earthquake waves move through the earth’s interior.
The Mantle is made up mostly of a rock called peridotite.
Mountains can be any feature that is higher than the surrounding land.
Mountains “float” on the mantle below. The higher the mountain is, the deeper the root. Mountains have vast “roots” to support them. The roots of a mountain are the thickest part of the mountain that sinks into the mantle.
If a mountain’s surface erodes away, the mountain weighs less and rises. The root also rises.
The four process of mountain building are: folding, faulting, uplift, and volcanism.
Fold Mountains: When sections of the crust and upper mantle are squeezed from opposite sides, the crust wrinkles and Fold Mountains are formed. The Appalachians are Fold Mountains.
Block Mountains: Block Mountains have a fault along at least one side. These kinds of mountains have a steep side and a sloping side. Example: The Teton Range in Wyoming
Dome Mountains: Dome Mountains form when large portions of the earth’s crust are pushed upward by magma. The Black Hills in South Dakota are Dome Mountains and made of igneous rock.
Volcanoes: Volcanoes are cone-shaped mountains that form when melted rock material piles up and hardens. Mount Hood in Oregon is a cone-shaped volcano.
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