03.05.a1 Ocean-Ocean Convergent Boundary One plate moves down = subduction Two oceanic plates move toward one another Trench and island arc

03.05.a1 Sketch ocean-ocean convergence, labeling the processes in your own words Slab releases water Eruptions form volcanic island arc Water causes melting of mantle Accretionary prism Features and Processes in Ocean-Ocean Convergence Trench

03.05.b1 Ocean-Continent Convergent Boundary Sketch ocean-continent convergence, labeling the processes in your own words Oceanic plate subducted beneath continent Oceanic and continental plate converge Overlying mantle melted Volcanoes and squeezing form mountain belt Trench

03.05.c1 Observe the distribution of volcanoes around the Pacific Ring of Fire What do you think could explain the overall pattern?

Pacific Ring of Fire c2 Subduction beneath oceanic plates = island arcs (e.g., Japan) Oceanic plates subducted on both sides Subduction beneath continental plates = mountain belts with volcanoes (e.g., Andes) Explain the Pacific Ring of Fire, including why the west and east sides are different Spreading in East Pacific Rise

03.05.d Continent-Continent Convergence Subduction brings continents closer Subduction of oceanic part of plate Continents collide Two continents collide

03.05.d3 Sketch a continental collision, labeling the processes in your own words Pieces sliced off Continental collision = wide zone of deformation Continental plate buoyant, so subduction ends Few volcanoes Thick crust = high elevation

03.06.a1 Transform Boundary Observe how these two “plates” are moving past each other Transforms link other types of plate boundaries Plates move horizontally past one another on transform boundaries Transforms link spreading segments in mid-ocean ridges

03.06.a2 Observe the pattern of the Mid-Atlantic Ridge Transforms link spreading segments Spreading segments Sketch a transform boundary, labeling the processes in your own words

03.06.b1 Observe plate boundaries near the west coast of North America (green lines are transform boundaries)

03.07.a1 What Moves the Plates? Ridge push Slab pull Other forces, such as convection in mantle

03.07.b1 Rates of Relative Plate Movement Which plate boundaries have the fastest rates? Some move faster than others Plates move cm/year

03.07.d1 Geometry of Plate Boundaries Observe how the motion of these two plates varies as the boundary changes orientation Transform boundaries link other types of plate boundaries, like two spreading centers or a spreading center with a subduction zone As boundary changes orientation, plates move horizontally past one another Spreading along this orientation

03.07.d1 Geometry of Plate Boundaries II Observe how the motion between the North American and Pacific plates varies as the boundary changes orientation Transform boundary here (Queen Charlotte fault), with plates moving horizontally past one another As boundary bends, becomes convergent (Pacific plate subducted beneath NA)

03.08.a1 Sediment thickens away from ridge (had more time to accumulate) Volcanic rocks in crust youngest near ridge (just formed) Test of Plate Tectonics Is Age of Seafloor and Thickness of Sediment Drill cores Sediment Volcanic rocks

Formation of Linear Island and Seamount Chains Plate moves over a hot spot Lines of islands and seamounts (e.g., Hawaii) Volcano forms over a hot spot Volcanoes become inactive as area moves away from hot spot Plate subsides as cools, so islands become seamounts c

03.09.a1 Why is South America Lopsided Observe the features around South America Envision a cross section from west of South America to the Mid- Atlantic Ridge

03.09.b1 Compare this cross section with the one you envisioned Eastern edge of continent not a plate boundary (passive margin) Spreading along mid-ocean ridge Subduction beneath western edge Andes (mountains and volcanoes) over subduction zone, with trench offshore

03.09.c Evolution of South America Observe the evolution of South America, beginning with continental rifting away from South America Middle Mesozoic (140 m.y ago) Late Mesozoic (100 m.y ago) Present

03.10.a1 Investigation: Where is the Safest Place to Live Identify possible plate boundaries in this area and indicate whether the boundary is divergent, convergent, or transform Continent A Continent B Identify where you would get earthquakes and volcanoes, and then determine where it is safest to live

03.10.a Sketch the geometry of the plates in the subsurface, using figures in the textbook as a guide to the geometries of the plates and thickness of the lithosphere, oceanic crust, and continental crust