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Plate Boundaries ~ Plate Movement ~ Plate names ~ Types of landforms/Effect of plate boundaries ~ Names of landforms Maps & Information
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Plate Boundaries: The point at which two tectonic plates meet is called a plate boundary. It is at these locations where tectonic activity results in earthquakes, volcanoes and the formation of mountain ranges due to the movement of the plates.
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This map shows 15 of the largest plates. Note that the Indo-Australian Plate may be breaking apart into the Indian and Australian plates, which are shown separately on this map.
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World map showing plate boundaries (blue lines), the distribution of recent earthquakes (yellow dots) and active volcanoes (red triangles). Courtesy of NASA.
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The diagram below shows the major plates and their boundaries
The diagram below shows the major plates and their boundaries. The arrows indicate the direction of movement at each plate. It is the direction of movement as well as the difference in crust which determine the variations in processes and landforms at the different plate boundaries. (animation from USGS)
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Find HOTSPOTS: Hawaii, Canary Islands, Yellowstone, Iceland, Galapagos
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At the edges of the plates we see the ridges and trenches that gave the first clues to Plate Tectonics. There are a few theories that control what happens along these edges, or plate boundaries as they are called.
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Map showing the global distribution of tectonic plates and plate boundaries. The black arrows and numbers give the direction and speed of relative motion between plates. Speed of motion is given in mm y−1. (Adapted from Bott, 1982)
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Interactive Map of Plate Boundaries & Types of Boundaries
Source: Use the interactive map at the weblink below to see where the three different types of plate boundaries are found throughout the world. First, find the KEY in the green box located in the lower right-hand corner of the map. Then, roll your mouse over each boundary name in the KEY to see its location.
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GREAT RIFT VALLEY The red line on this map shows the eastern and western faults of the Great Rift Valley, which travels 4,500 miles from southern Africa, under the Red Sea, and into Syria in southwestern Asia. The red star is Nyiragongo volcano.
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Constructive Plate Boundaries – (aka Divergent or Tensional)
When two plates move away from each other creating a gap between them. Molten rock (magma) rises from the mantle to fill the gap forming a mid-ocean ridge - See more at: Constructive plate boundaries cause mid-ocean ridges, volcanoes and earthquakes, though often less violent than those on destructive plate boundaries.   Volcanoes can form along the edges of the plate boundary due to the rising magma. These volcanoes are called shield volcanoes.   Example: the North American plate moving away from the Eurasian plate formed the Mid-Atlantic Ridge and created Iceland through volcanic activity.
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Destructive Boundary aka Convergent Movement
Movement: Two plates moving towards each other (continental and oceanic crust) (note where two oceanic plates meet one will be subducted and an island arc will form) Processes: The denser oceanic crust is subducted underneath the continental crust forming a subduction zone and oceanic trench. As it is subducted it melts due to heat and pressure. The heat sources are friction between the two plates and from the earth's interior. Melting of the subducting plates creates magma which is lighter than the mantle and therefore rises resulting in the formation of volcanoes. Earthquakes also occur at this type of boundary due to the friction and pressure during subduction. Landforms Created: Fold Mountains and Ocean Trench Example: South American and Nazca Plates (forming the Andes and a deep sea trench (Peru-Chile trench))
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Constructive Boundary aka Divergent Movement
Movement: two plates moving away from each other Processes: As the two plates separate, hot magma is able to rise to fill the 'gap' creating new crust. As magma continues to build up, new mountain ranges form under the sea creating a mid-oceanic ridge. Where rising magma continues to build up above the ocean surface, a volcanic island is formed (for example Surtsey, Iceland). Both earthquakes and volcanoes occur at this type of boundary. Landforms Created: Ocean Ridge; Volcanic Islands Example: North American and Eurasian Plate - (forming the Mid-Atlantic Ridge)
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Movement: two plates moving away from each other (animation courtesy of USGS)
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Key Term Check Constructive Boundary (Divergent) - where two plates move away from each other resulting in new crust being formed. Destructive Boundary (Convergent) - where two plates move towards each other - in the case of a plate consisting of continental crust meeting a plate consisting of oceanic crust, the oceanic crust will be subducted and destroyed as it is less dense. Conservative Boundary - where two plates move alongside each other - although crust is neither created or destroyed here, earthquakes usually occur here. Collision Boundary - where two plates of continental crust move towards each other creating fold mountains. Volcano - a vent through which lava, ash etc. is erupted (often, but not always cone-shaped) Earthquake - a sudden ground movement
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Collision Boundary Convergent Boundary
Movement: two plates moving towards each other (both continental crust) Processes: As both plates consist of continental crust they both resist subduction and buckle and fold, being forced upwards to create fold mountains or a mountain range, such as the Himalayas. Although there is no volcanic activity at these locations, due to the forces of collision major earthquakes often occur here. Example: Indo-Australian and Eurasian Plate (forming the (Himalayas)
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Convergent Boundary click on title for website information
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Types of Convergent Boundary
Oceanic-Continental Convergence When an oceanic plate pushes into and subducts under a continental plate, the overriding continental plate is lifted up and a mountain range is created. Even though the oceanic plate as a whole sinks smoothly and continuously into the subduction trench, the deepest part of the subducting plate breaks into smaller pieces. These smaller pieces become locked in place for long periods of time before moving suddenly and generating large earthquakes. Such earthquakes are often accompanied by uplift of the land by as much as a few meters. Oceanic-Oceanic Convergence When two oceanic plates converge one is usually subducted under the other and in the process a deep oceanic trench is formed. The Marianas Trench, for example, is a deep trench created as the result of the Phillipine Plate subducting under the Pacific Plate. Oceanic-oceanic plate convergence also results in the formation of undersea volcanoes. Over millions of years, however, the erupted lava and volcanic debris pile up on the ocean floor until a submarine volcano rises above sea level to form an island volcano. Such volcanoes are typically strung out in chains called island arcs. Continental-Continental Convergence When two continents meet head-on, neither is subducted because the continental rocks are relatively light and, like two colliding icebergs, resist downward motion. Instead, the crust tends to buckle and be pushed upward or sideways. The collision of India into Asia 50 million years ago caused the Eurasian Plate to crumple up and override the Indian Plate. After the collision, the slow continuous convergence of the two plates over millions of years pushed up the Himalayas and the Tibetan Plateau to their present heights. Most of this growth occurred during the past 10 million years.
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Convergent Boundary Places where plates crash or crunch together are called convergent boundaries. Plates only move a few centimeters each year, so collisions are very slow and last millions of years. Even though plate collisions take a long time, lots of interesting things happen. For example, in the drawing above, an oceanic plate has crashed into a continental plate. Looking at this drawing of two plates colliding is like looking at a single frame in a slow-motion movie of two cars crashing into each other. Just as the front ends of cars fold and bend in a collision, so do the "front ends" of colliding plates. The edge of the continental plate in the drawing has folded into a huge mountain range, while the edge of the oceanic plate has bent downward and dug deep into the Earth. A trench has formed at the bend. All that folding and bending makes rock in both plates break and slip, causing earthquakes. As the edge of the oceanic plate digs into Earth's hot interior, some of the rock in it melts. The melted rock rises up through the continental plate, causing more earthquakes on its way up, and forming volcanic eruptions where it finally reaches the surface. An example of this type of collision is found on the west coast of South America where the oceanic Nazca Plate is crashing into the continent of South America. The crash formed the Andes Mountains, the long string of volcanoes along the mountain crest, and the deep trench off the coast in the Pacific Ocean.
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Divergent Boundary Movement: two plates moving way from each other ()
Places where plates are coming apart are called divergent boundaries. As shown in the drawing above, when Earth's brittle surface layer (the lithosphere) is pulled apart, it typically breaks along parallel faults that tilt slightly outward from each other. As the plates separate along the boundary, the block between the faults cracks and drops down into the soft, plastic interior (the asthenosphere). The sinking of the block forms a central valley called a rift. Magma (liquid rock) seeps upward to fill the cracks. In this way, new crust is formed along the boundary. Earthquakes occur along the faults, and volcanoes form where the magma reaches the surface.
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Divergent Boundary Movement:Â two plates moving way from each other () Processes:Â Where a divergent boundary crosses the land, the rift valleys which form are typically kilometers wide. Example 1::Â include the East Africa rift in Kenya & Ethiopia, and the Rio Grande in New Mexico. Where a divergent boundary crosses the ocean floor, the rift valley is much narrower, only <1 km across, and it runs along the top of a mid-oceanic ridge. Oceanic ridges rise a KM or so above the ocean floor and form a global network tens of thousands of miles long. Example 2: Mid-Atlantic ridge (widens only 2 cm per year) and the East Pacific Rise
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Transform Boundary aka Conservative Boundary
Movement: two plates moving alongside each other Processes: crust is neither created or destroyed here but as both pressure and friction results during the movement of the plates side by side, a 'stick-slip' motion results in the creation of significant earthquakes. Pressures builds up due to friction between the plates and when the plates break apart the energy is sent through the earth as seismic waves in the form of an earthquake. Example: San Andreas Fault - North American and Pacific Plates
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Transform Boundary
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Transform Boundary Places where plates slide past each other are called transform boundaries. Since the plates on either side of a transform boundary are merely sliding past each other and not tearing or crunching each other, transform boundaries lack the spectacular features found at convergent and divergent boundaries. Instead, transform boundaries are marked in some places by linear valleys along the boundary where rock has been ground up by the sliding. In other places, transform boundaries are marked by features like stream beds that have been split in half and the two halves have moved in opposite directions.
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Transform Boundary Perhaps the most famous transform boundary in the world is the San Andreas fault, shown in the drawing above. The slice of California to the west of the fault is slowly moving north relative to the rest of California. Since motion along the fault is sideways and not vertical, Los Angeles will not crack off and fall into the ocean as popularly thought, but it will simply creep towards San Francisco at about 6 centimeters per year. In about ten million years, the two cities will be side by side!
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Hotspots You should be aware that while most volcanoes or earthquakes occur along plate boundaries, there are exceptions. For example the volcanic Hawaiian islands which can be found in the middle of the Pacific Plate are formed due to a Hotspot. Hotspots are plumes of molten rock which rise underneath a plate causing localized melting and the creation of magma resulting in volcanic activity.
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This Dynamic Planet site by USGS
 Inset I - Divergent Boundaries - PDF file | French  Inset II - Convergent Boundaries: Subduction - PDF file | French  Inset III - Convergent Boundaries: Collision - PDF file | French  Inset IV - Bedrock Age Map - PDF file | French  Inset V - Hotspots - PDF file | French  Inset VI - Impact Craters - PDF file | French  Inset VII - Transform Plate Boundaries - PDF file | French  Tables Notable Events - PDF file  Timelines - PDF file  Map Text - PDF file  References - PDF file
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A Few Theories of Plate Tectonics
1. Continental crust is less dense, or lighter, than Oceanic crust so it doesn't sink. It is never destroyed and is permanent. 2. Oceanic crust is heavier so it can sink below Continental crust. It is constantly being formed and destroyed at ocean ridges and trenches. 3. Continental crust can carry on beyond the edges of the land and finally end far below the sea. This explains why the edges of all the continents don't have deep trenches right up against their coastlines. 4. Plates can never overlap. This means that they must either collide and both be pushed up to form mountains, or one of the plates must be pushed down into the mantle and be destroyed. 5. There can never be gaps between plates, so if two plates move apart, as in the middle of the Atlantic, new rock will be formed to fill the space. 6. We know the Earth isn't getting bigger or smaller, so the amount of new crust being formed must be the same as the amount being destroyed. 7. Plate movement is very slow. This is partly why Wegener's original ideas were ignored. Nobody could 'see' the continents moving. When the plates make a sudden movement we call it an Earthquake, and it's the only time we are directly aware of the plates moving.
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PLATE BOUNDARIES: The point where two or more plates meet is known as a plate boundary. It is at these locations where earthquakes, volcanoes and fold mountain form. There are four main types of plate boundary. These are constructive, destructive, conservative and collision margins. Plate Boundary Diagram Description Landforms Example Tensional / Constructive(divergent ) plate boundaries Constructive plate boundaries occur when two plates move away from each other. Ocean ridge and volcanic islands North American and Eurasian Plate Compressional / Destructive(subduction zones) plate boundaries Destructive plate boundaries occur when an oceanic plate is forced under (or subducts) a continental plate. Fold Mountains and Oceanic trenches Pacific Plate and the Eurasian Plate Conservative(transform faults) plate boundaries Conservative plate boundaries occur when two plates slide past each other. North American Plate and the Pacific Plate Collision plate boundaries Collision plate boundaries occur when two continental plates move towards each other. Fold Mountains Indo-Australian and the Eurasian Plate
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Landform Results @ Plate Boundaries
Type of Boundary Plate Movement Example CONSTRUCTIVE (divergent) Two plates of oceanic crust moving apart from each other. Two plates of continental crust moving apart from each other. The America's moving away from the Eurasian and African Plates - formed the Mid-Atlantic Ridge. East-African Rift Valley DESTRUCTIVE (convergent) Two plates moving together - may be ocean and continental or oceanic and oceanic Nazca and South American Plate (Oceanic and Continental) - formed the Peru-Chile Deep Sea Trench and the Andes COLLISION (convergent) Two plates moving together (continental and continental) Indian and the Eurasian Plate - formed the Himalayas CONSERVATIVE two plates moving parallel to each other - land neither created nor destroyed North American and Pacific Plate - The San Andreas Fault
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Continental to Continental
Converging Crusts Ocean to Ocean Continental to Continental Oceanic-oceanic collision forces the edges of the upper mantle down due to the cold basalt in the ocean's crust. Oceanic-continental collisions form crust beneath a descending granite crust, which is too light to sink into the mantle. Continental-continental plate collisions have rocks on both sides that are too light to sink into the earth's mantle. This causes the edges to crumble and fold into mountain regions. The Himalayas are the best known example of this occurrence. This mountain region resulted when Asia and India crashed into each other. Little melting occurred during this collision because few rocks were forced to great depths. This caused the formation of only a few volcanoes. Source read more:Â Volcanoes in the Himalayas | eHow.comÂ
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This map shows current movements of the Eurasian, African, Indian and Arabian lithospheric plates relative to the Global Positioning System (GPS) satellite network. The differences among individual stations are due to deformation of the plates at their edges and distortion produced by the Mercator projection of the map. The information on this map was last updated in August 2002. The Global Positioning System (GPS) is a constellation of 30 satellites which is used for navigation and precise geodetic position measurements. Data from over 2000 receivers have been analyzed at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration. JPL's GIPSY software is used to produce these time series and other useful data products. Horizontal velocities, mostly due to motion of the Earth's tectonic plates, are represented on the map by lines extending from each site. Click on a dot or name to see detailed time series for a particular site. Additional information may be obtained
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This map shows current movements of the North and South American, Pacific, Nazca, Australian, Philippine and Antarctic lithospheric plates relative to the Global Positioning System (GPS) satellite network. The differences among individual stations are due to deformation of the plates at their edges and distortion produced by the Mercator projection of the map. The information on this map was last updated in August 2002.
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3 Types of Boundaries - Requirements
Title & Name 3 - Labeled diagrams of each type of boundary 3 – Detailed descriptions of each type of boundary including plate movement & types of crust 3 – types of landforms/effect of boundary 3 – examples of landforms/effect of boundary
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3 Types of Boundaries - Requirements
Students should be able to label major plates (e.g. African, Pacific, Eurasian, North American, Arabian, etc.) Students should be able to determine type of plate movement (e.g. Eurasian & Indian plate => converging – collision) AND landform created at plate boundaries (mountain) AND and example (Himalayas)
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3 Types of Boundaries - Requirements
Students should know the cause of the following: Mid-Atlantic Ridge East African Ridge Himalayas Andes San Andreas Fault Hawaiian Islands & Aleutian Islands
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Picture is hyperlinked
Picture is hyperlinked. Students should be able to label I, N, J, B, L, D, G, and K plates.
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Resources Plate Tectonics ; covers a variety of topics
Evolution of Continents & Oceans by Indiana University Different Plate Boundaries Create Different Landforms and Events ; covers types of processes Plate Tectonics by Dept of Natural Resources; covers a variety of topics
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