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Describe the differences and relation between the lithosphere and asthenosphere. Name the three types of plate boundaries and the general characteristic of plate movement along each plate boundary. What is the magnetic field and how is it formed?. Plate Boundaries. Convergent Divergent
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Describe the differences and relation between the lithosphere and asthenosphere.
Name the three types of plate boundaries and the general characteristic of plate movement along each plate boundary.
Plate Boundaries Convergent Divergent Transform
Plate Tectonics • Explains the configuration of topographic features of the Earth- mountains, valleys, volcanoes, islands, oceanic trenches, faults
Tectonic plates • Are composed of the lithosphere • Move as a coherent mass • May contain oceanic crust and continental crust
Direction of Movement • Perpendicular to mid-oceanic ridges
Plate Boundaries • Concentration of stored energy and ultimately release of energy • Production of hazards Topographic features on the Earth’s surface reflects what is happening in the mantle.
Magmatic arc Oceanic crust subducts under continental crust Melting occurs at about 100 miles Hot more buoyant material rises Convergent Plate Boundary
Volcanic Arc • Oceanic and continental crust • Cascade Range, Andes, Alaska • Characteristics: large volcanoes; subduction zone; trench; oceanic crust subducts under continental crust
Convergent Plate Boundary • Map and cross-section views of the subduction zone • The oceanic Juan de Fuca plate subducts under the continental North American Plate
Two oceanic crusts Oceanic crust subducts under opposing oceanic crust Oldest oceanic crust subducts Convergent Plate Boundary
Island Arc • Japan, Indonesia, Philippines, Caribbean, Aleutian Islands
Earthquakes trace the subducting slab to about 500 miles or 650 kilometers Convergent Plate Boundary Gold dots represent earthquake hypocenters
Convergent Plate Boundaries • Two continental crusts • Neither subduct due to buoyancy of crusts • Mountains form
India collided with Asia about 40 million years ago • Mt. Everest, 29,000 feet
Divergent Plate Boundary • Two plates move apart • Run through ocean basins
Divergent Plate Boundaries Mid-oceanic ridges, transform faults and rift valleys, and the formation of the ocean floor are characteristics associated with divergent plate boundaries.
Transform Plate Boundary • The tectonic plate pass by each other • Connect other plate boundaries • San Andreas Fault
Extension-“Pre-divergent Boundary” Continental crust begins to stretch due to tensional stress.
Basin and Range • Continental crust begins to stretch due to convection within the asthenosphere • A series of mountains and valleys develop • Long Valley Caldera is located on the western most portion.
East Africa Rift Zone • An area of extension • Continental crust is beginning to pull-apart forming a rift valley
HotSpots • Stationary plumes of hot material that initiate at the core/mantle interface • Hawaii: the plume is beneath oceanic crust
Hot Spots • Yellowstone is associated with a hot spot under continental crust
Plate Tectonics • The theory of plate tectonics is based on the evaluation of scientific evidence and observation- The Scientific Method • Continental Drift hypothesis • Seafloor Spreading hypothesis
Sketch a cross section of a divergent plate boundary. • Label with the following terms: • rift valley; • oceanic ridge; • oceanic crust; • location of melting and volcanism; • and arrows indicating direction of plate movement .
Sketch a cross-section of a convergent plate boundary that contains an oceanic crust. • Label with the following terms: • Subduction zone • Trench • Area of melting • Area of volcanism • Arrows indicating direction of plate movement
Name the landform associated with oceanic crust subducting under continental crust. Oceanic crust?