Plate Boundaries and Plate Interactions There are three different types of plate boundaries, classified according to their relative motions: divergent boundaries; convergent boundaries; and transform, or parallel slip, boundaries. Divergent boundaries occur where plates are spreading apart. Young divergence is characterized by thin or thinning crust and rift valleys; if divergence goes on long enough, midocean ridges eventually develop, such as the Mid-Atlantic Ridge and the East Pacific Rise. Convergent boundaries occur where plates are moving toward each other. At a convergent boundary, material that is dense enough, such as oceanic crust, may sink back into the mantle and produce a deep ocean trench. This process is known as subduction. The sinking material may partially melt, producing volcanic island arcs, such as the Aleutian Islands and Japan. If the subduction of denser oceanic crust occurs underneath a continent, a volcanic mountain chain, such as the Andes or the Cascades, is formed. When two plates collide and both are too light to sub-duct, as when one continent crashes into another, the crust is crumpled and up-lifted to produce great mountain chains, such as the relatively young Himalayas or the more ancient Appalachians. The third type of plate boundary, called a transform, or parallel slip, boundary, comes into existence where two plates move laterally by each other, parallel to the boundary. The San Andreas fault in California is an important example. Marking the boundary between the North American and Pacific plates, the fault runs from the Gulf of California northwest to Mendocino County in northern California.

Goals Classify and label the types of movement at plate boundaries, using a world map that shows relative plate motions Identify the distribution of plates by means of the world map of relative plate motions Describe the present plate-tectonic setting of your community, and infer possible past plate-tectonic activity based on your knowledge. Use the Blackline Master to make an overhead of figure 5 on page 85. This map can be incorporated into a discussion on transform plate boundaries. Most students are aware that earthquakes frequently occur in California, and you may point out to them these quakes are the result of stress release along a transform plate boundary. This will introduce the idea that earthquakes occur along plate boundaries, a concept addressed in Activity 4.

Divergent Plate Boundary Convergent Plate Boundary Transform Plate Boundary

Think About It Write a caption for this cartoon. The most interesting ride on a plate would be the leading or trailing plate. Scan picture on page 76 and add to this slide.

Investigate page 79 Answer Part C and Part D Read Digging Deeper pg. 80-85 Answer questions #1-7 on page 85 in your comp book. No you don’t have write the questions in your comp book, but only if you write a complete answer. Add the Geo words into your illustrated glossary.

Divergent Plate Boundary 3. b. Students know the principal structures that form at the three different kinds of plate boundaries. There are three different types of plate boundaries, classified according to their relative motions: divergent boundaries; convergent boundaries; and transform, or parallel slip, boundaries. Divergent boundaries occur where plates are spreading apart. Young divergence is characterized by thin or thinning crust and rift valleys; if divergence goes on long enough, midocean ridges eventually develop, such as the Mid-Atlantic Ridge and the East Pacific Rise. Convergent boundaries occur where plates are moving toward each other. At a convergent boundary, material that is dense enough, such as oceanic crust, may sink back into the mantle and produce a deep ocean trench. This process is known as subduction. The sinking material may partially melt, producing volcanic island arcs, such as the Aleutian Islands and Japan. If the subduction of denser oceanic crust occurs underneath a continent, a volcanic mountain chain, such as the Andes or the Cascades, is formed. When two plates collide and both are too light to sub-duct, as when one continent crashes into another, the crust is crumpled and up-lifted to produce great mountain chains, such as the relatively young Himalayas or the more ancient Appalachians. The third type of plate boundary, called a transform, or parallel slip, boundary, comes into existence where two plates move laterally by each other, parallel to the boundary. The San Andreas fault in California is an important example. Marking the boundary between the North American and Pacific plates, the fault runs from the Gulf of California northwest to Mendocino County in northern California. It’s a plate boundary where two plates move away from one another Example: South American & African Plate

Divergent Plate Boundary Young divergence has thin or thinning crust and rift valleys Example: Mid Ocean Ridge and East Pacific Rise

Divergent Boundaries 3. b. Students know the principal structures that form at the three different kinds of plate boundaries. There are three different types of plate boundaries, classified according to their relative motions: divergent boundaries; convergent boundaries; and transform, or parallel slip, boundaries. Divergent boundaries occur where plates are spreading apart. Young divergence is characterized by thin or thinning crust and rift valleys; if divergence goes on long enough, midocean ridges eventually develop, such as the Mid-Atlantic Ridge and the East Pacific Rise. Convergent boundaries occur where plates are moving toward each other. At a convergent boundary, material that is dense enough, such as oceanic crust, may sink back into the mantle and produce a deep ocean trench. This process is known as subduction. The sinking material may partially melt, producing volcanic island arcs, such as the Aleutian Islands and Japan. If the subduction of denser oceanic crust occurs underneath a continent, a volcanic mountain chain, such as the Andes or the Cascades, is formed. When two plates collide and both are too light to sub-duct, as when one continent crashes into another, the crust is crumpled and up-lifted to produce great mountain chains, such as the relatively young Himalayas or the more ancient Appalachians. The third type of plate boundary, called a transform, or parallel slip, boundary, comes into existence where two plates move laterally by each other, parallel to the boundary. The San Andreas fault in California is an important example. Marking the boundary between the North American and Pacific plates, the fault runs from the Gulf of California northwest to Mendocino County in northern California.

Convergent Plate Boundary A plate boundary where two plates go toward each other The denser crust will always subduct beneath the other crust. Sometimes these make ocean trenches. Nazca plate & South American Plate

Convergent Plate Boundary If denser oceanic crust subbducts beneath continental crust, a volcanic chain Ex) Andes or the Cascades

Convergent Plates The sinking material can partially melt. This makes volcanic island arcs. Ex) Aleutian islands and Japan

Convergent Plate Boundary When 2 continents collide that are both to light to subduct the crust is crumpled and uplifted to make great mountain chains – ex) Himalayas and Appalachian

Transform Plate Boundary When two plates move parallel from each other San Andreas Fault AKA: parallel slip 3. b. Students know the principal structures that form at the three different kinds of plate boundaries. There are three different types of plate boundaries, classified according to their relative motions: divergent boundaries; convergent boundaries; and transform, or parallel slip, boundaries. Divergent boundaries occur where plates are spreading apart. Young divergence is characterized by thin or thinning crust and rift valleys; if divergence goes on long enough, midocean ridges eventually develop, such as the Mid-Atlantic Ridge and the East Pacific Rise. Convergent boundaries occur where plates are moving toward each other. At a convergent boundary, material that is dense enough, such as oceanic crust, may sink back into the mantle and produce a deep ocean trench. This process is known as subduction. The sinking material may partially melt, producing volcanic island arcs, such as the Aleutian Islands and Japan. If the subduction of denser oceanic crust occurs underneath a continent, a volcanic mountain chain, such as the Andes or the Cascades, is formed. When two plates collide and both are too light to sub-duct, as when one continent crashes into another, the crust is crumpled and up-lifted to produce great mountain chains, such as the relatively young Himalayas or the more ancient Appalachians. The third type of plate boundary, called a transform, or parallel slip, boundary, comes into existence where two plates move laterally by each other, parallel to the boundary. The San Andreas fault in California is an important example. Marking the boundary between the North American and Pacific plates, the fault runs from the Gulf of California northwest to Mendocino County in northern California.

San Andreas Fault SAF is the boundary between the North American and Pacific plates. The fault runs from the Gulf of Calif. NW to Mendocino County in N. California

Transform Plate Boundaries

Transform Plate Boundaries

Homework Visit the following website and record examples of each type of plate boundary into your comp book. http://geology.com/plate-tectonics.shtml Study for your quiz on Tuesday Tectonic Setting for Volcanic Activity animations www.agiweb.org/earthcomm/

Warm-Up Write a brief definition for each of the following terms and give an example of where you might find each: Divergent Plate Boundary Convergent Plate Boundary Transform Plate Boundary You should find a god animation of each of these types of plate boundaries.

Warm-Up Convergent boundaries can be in three different settings. What are they? Name the 3 types of boundaries between lithospheric plates What happens when two continent plates collide along a convergent plate boundary?