Earth’s History
Chapter 4 Lesson 1
Objectives
•List 5 categories of mountains and describe how each type of mountain forms.
•Identify major California mountain ranges on a relief map.
Main Idea
•Mountains ______from ______.
Vocabulary
•______– (noun), a mountain range formed by magma that escaped from Earth’s interior, then cooled.
•______– (noun), a block of crust that is pushed upward along a fault.
•______– (noun), area where a magma plume rises in the mantle and erupts through a plate.
•______– (noun), a dome-shaped mound that forms in Earth’s crust from magma that rises but does not break through.
•______– (noun), a folded piece of crust formed where continental plates collide.
Building Background
A mountains form primarily at the boundaries of ______, due to the motions that deform the crust or bring magma from the Earth’s interior to the surface.
Folding and Faulting Forces
•______are Earth’s tallest landforms. Because mountains are so huge you may think they are ______. But that is not ______. Mountains are continually being ______or ______. The actions of ______build up mountains, while ______and ______wear them down.
•Most ______form near plate boundaries, especially where two ______push together. In these zones, ______are common.
•Over time, ______wears down and softens the ______. That is why some mountains have ______peaks. In other cases, stress on the crust causes it to ______instead of ______. This creates ______, or ______, in the crust. ______may form wherever faulting occurs. This type of mountain forms from a block of ______that is pushed ______or ______along a fault.
•In most cases, ______form when stress splits the crust. Land on one side of the ______is raised, while the other side drops ______.
•As with ______, erosion helps shape ______. ______mountains have softer edges. Many valleys near the ______are partly filled with material that has ______from nearby mountainsides.
•California’s Death Valley is a block of land that has dropped between ______. It dropped so far that ______is the lowest point in the United States.
•What are the 5 categories into which mountains are classified?
______
Volcanic Forces
•Volcanic activity often happens at ______, when the edge of one plate ______another. The edge of the sinking plate melts into ______deep underground. If it bursts through the ______, it can build up over time to form a ______.
•At ______, magma rises up in the gap between the two plates that are pulling apart. Recall that ______form in this way at divergent boundaries on the ocean floor. The buildup of cooled magma under the sea has created the world’s longest ______.
•Volcanic mountains can form away from ______as well. Magma plumes rising from the ______create ______under some areas of the crust. As a plate moves over a hot spot, ______can erupt through the plate, creating ______.
•Sometimes, ______rises toward the surface but doesn’t break through the ______. It may push up ______, creating a ______.
•What are the steps in the formation of a mid-ocean ridge?
______
Erosion Mountains
•Weathering and ______continually shape Earth’s ______. Although mountains can be affected by these forces, a few ______were formed entirely by them. These are called ______. The ______in New York State are one example. The Catskills were once a ______, or raised area of flat land. Mountains began forming during the last ______, when glaciers carved the plateau into peaks and valleys. Later, ______further sculpted the land.
•Erosion has shaped other kinds of ______after they formed originally. The results are ______and valleys. California’s largest mountain, range the ______, was also shaped by ______. Glaciers shaped some of the ______and ______out bowls, now filled with small lakes. ______also widened V-shaped mountain valleys into ______now seen in parts of the Sierras.
•How are dome mountains different from most other mountains?
______
California Mountains
•Most of California is on the ______. Some of western California is on the ______. The movements of these plates have helped ______the mountains of California.
•The Sierra Nevada chain is a huge range of ______. The mountains are a block of ______tilted ______from a fault that runs along their edge.
•Other mountain ranges in California are the result of ______forces that ______and ______Earth’s crust. ______mountains form as a result. About 30 million years ago, the interaction between the ______and ______pushed up the ______. These include the ______and ______. As the plates slipped past each other, the ocean floor ______and ______to form the mountains.
•Mount Shasta and ______are ______mountains that are part of the Cascades. The Cascade Range is a chain of ______, formed where several smaller tectonic plates are ______beneath the North American Plate.
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