Chapter 5, Lesson 2, California Geology

Chapter 5, Lesson 2, California Geology, Slide 1 *What is the main idea? _______________ -What are plate tectonics in California like? *Many of California’s landforms were produced by plate tectonic activity, which continues today. __________________________________________________ _ -Movements of plates have changed California dramatically. -Seas have disappeared, old mountains have eroded away, and new mountains have been uplifted. -At the northern end of California, a convergent plate boundary sits offshore and produces earthquakes, volcanoes, and mountains.

Chapter 5, Lesson 2, California Geology, Slide 2 *What is California’s transform plate boundary? *A small part of California, west of the San Andreas Fault, lies on the Pacific Plate. *The San Andreas Fault is a transform plate boundary that is located between the North American Plate and the Pacific Plate. *Because the San Andreas Fault is a transform plate boundary, it is also a strike-slip fault. *It extends all the way from Mendocino in the northern part of California to the Salton Sea in the south.

Chapter 5, Lesson 2, California Geology, Slide 3 -What is California’s convergent plate boundary? -Offshore of Northern California, there are two small oceanic lithospheric plates. -These plates are known as the Gorda and Juan de Fuca. -They are subducted beneath the coast at the Cascadia Subduction Zone. -This subduction forms a convergent plate boundary. - Melting above this subduction zone produces the volcanic mountains of the Cascade Range.

Chapter 5, Lesson 2, California Geology, Slide 4 *How were California’s mountains formed? *California’s mountains often formed from interactions at several plate boundaries. *Convergent plate boundaries, both in the past and the present, have been important in forming California’s mountains. *During mountain building, compressive stresses and heat produce metamorphic rocks that form where plates converge. *The Klamath Mountains, Coastal Ranges, Peninsular Ranges, and Sierra Nevada, all contain igneous and metamorphic rocks that formed far below the surface.

Chapter 5, Lesson 2, California Geology, Slide 5 *How were California’s mountains formed? (Continued) *There are even some mountains in California that have formed because of tension stresses. *The Panamint Range just west of Death Valley is rising up as the crust in eastern California stretches. *Mountains help scientists understand the processes that are part of California’s rich tectonic history.

Chapter 5, Lesson 2, California Geology, Slide 6 *How were California’s mountains formed? (Continued)

Chapter 5, Lesson 2, California Geology, Slide 7 -Summary -Most of California is located on the North American Plate. -The San Andreas Fault is a transform plate boundary and strike- slip fault that extends from from Cape Mendocino to the Salton Sea. -Convergent plate boundaries make up most of California’s mountain ranges. -There are some mountains, such as the Panamint Range, that have formed because of tension stresses.