PLATE BOUNDARIES AND CALIFORNIA Chapter 5 THE BIG

PLATE BOUNDARIES AND CALIFORNIA Chapter 5

THE BIG IDEA California is located on a plate boundary, where major geologic events occur. Lesson 1: Interactions at Plate Boundaries There are three main types of plate boundaries, where stresses cause rocks to deform. Lesson 2: California Geology Many of California’s landforms were produced by plate tectonic activity, which continues today.

LESSON 1: INTERACTIONS AT BOUNDARIES PLATE There are three main types of plate boundaries where stresses cause rocks to deform. What you’ll learn: • Describe types of stress that deform rock. • Relate geologic features of Earth’s surface to types of plate boundaries. So What? ! Understanding geologic events that occur at plate boundaries can save lives and prevent damage to property.

REVIEW VOCABULARY Lithospheric Plate: Large, brittle pieces of Earth’s outer shell composed of crust and uppermost mantle.

NEW VOCABULARY rift valley fault Divergent P. B. Transform P. B. Long, narrow valley formed as the hanging wall of a divergent boundary slips down. Fracture in which rocks on one side of the fracture move relative to rocks on the other side. Boundary formed where plates move apart Boundary formed when two plates move sideways past each other.

NEW VOCABULARY fracture continental rifting Convergent P. B. Break or crack in rock Process that pulls apart a continent. Boundary formed when two plates move toward each other.

ACADEMIC VOCABULARY inclined Sloping, slanting, or leaning relative to the horizontal or vertical The Leaning Tower of Pisa inclines about 3. 99 degrees. In other words, the top of the tower is displaced horizontally 12 ft 10 in from where it would be if the structure were perfectly vertical.

DRIFTING CONTINENTS Types of Rock Stress Tension Compression Shear Rocks are pulled apart; causes stretching and thinning of the lithosphere. Rocks are pushed together; makes rock layer thick. Rocks are pushed in opposite directions; neither thickens nor thins lithosphere

3 MAIN TYPES OF FAULTS v Normal Fault v Reverse Fault v Strike-Slip Fault

SUMMARIZE IT Rephrase the main ideas of this section in your own words.

TYPES OF PLATE BOUNDARIES Sequence the events that occur during continental rifting. A continent splits apart at a divergent plate boundary. Tension stress causes rocks to break and form normal faults. The hanging wall slips down and forms a rift valley.

TYPES OF PLATE BOUNDARIES Distinguish 3 types of convergent plate boundaries. Describe what happens at each type of boundary. Ocean-to-Ocean-to-Continent-to-Continent Colder, denser slab is forced down, forming a trench; water is released and melts rocks, forming magma. Denser ocean plate always sinks below continental plate; melting forms a string of volcanoes along edge of continent. Compression forces force crust to rise, forming tall mountains.

TYPES OF PLATE BOUNDARIES Complete this paragraph about transform plate boundaries. At transform plate boundaries, plates Move sideways past each other _______________. In the ocean, these pieces of mid-ocean ridges boundaries connect ____________. large earthquakes can occur along these On the continents, _________ boundaries.

SUMMARIZE IT! Summarize three (3) main ideas of the above sections.

LESSON 2: PLATE BOUNDARIES AND CALIFORNIA Many of California’s landforms were produced by plate tectonic activity, which continues today. What you’ll learn: • Describe California’s current plate tectonic setting and how plate movements have produced landforms. • Predict future changes in California’s tectonic setting and topography. So What? ! Interactions between the North American Plate and the Pacific Plate produce California’s mountains and basins and cause earthquakes and volcanoes.

REVIEW VOCABULARY uplift Any process that moves Earth’s surface to a higher elevation.

NEW VOCABULARY San Andreas Fault The S. A. F. is a transform boundary (and a strike-slip fault) between the N. A. Plate and the Pacific Plate. It extends all the way from Cape Mendocino in the north to the Salton Sea in the south.

ACADEMIC VOCABULARY adjacent Next to or very near * The San Andreas Fault is a boundary between two adjacent plates.

PLATE TECTONICS IN CALIFORNIA Distinguish two plate boundaries found in California. 1. The San Andreas Fault System, a continental transform boundary cutting across the state. 2. A convergent plate boundary offshore in the northern part of the state.

PLATE TECTONICS IN CALIFORNIA Identify three features of California geology caused by plate tectonics. 1. earthquakes 2. volcanoes 3. mountains

PLATE TECTONICS IN CALIFORNIA Create a diagram showing the San Andreas Fault.

SUMMARIZE IT! Summarize the main ideas of the above section of the lesson.

PLATE TECTONICS IN CALIFORNIA Analyze the role of a convergent plate boundary in shaping CA geology. The Gorda and Juan de Fuca plates are forced beneath the coast. Melting above the subduction zone produces the volcanic mountains in the Cascade Range.

CALIFORNIA’S MOUNTAINS Organize information about the formation of mountains in California. I. Subduction A. Granite rocks formed under volcanic mountains when plates B. converged. An ancient oceanic plate subducted, forming rocks in several mountain ranges. II. Rifting A. Tension stresses cause continental rifting. B. Panamint Range rises as the crust stretches.

FUTURE PLATE MOVEMENTS Summarize two changes that might occur in the future as a result of plate tectonics. v The Pacific Plate will keep moving northwest, bringing Los Angeles and San Francisco closer. v Death Valley and the Gulf of California are dropping and opening up as a result of tension stress.

SUMMARIZE IT! Rephrase the main ideas of the lesson in your own words.