03.05.a1

Ocean-Ocean Convergent BoundaryOcean-Ocean Convergent Boundary

One plate moves One plate moves down = down = subductionsubduction

Two oceanic plates Two oceanic plates move toward one move toward one anotheranother

Trench and island arcTrench and island arc

03.05.a1

Sketch ocean-ocean convergence, labeling the Sketch ocean-ocean convergence, labeling the processes in your own wordsprocesses in your own words

Slab releases waterSlab releases water

Eruptions form volcanic Eruptions form volcanic island arcisland arc

Water causes Water causes melting of mantlemelting of mantle

Accretionary Accretionary prismprism

Features and Processes in Ocean-Ocean ConvergenceFeatures and Processes in Ocean-Ocean Convergence

TrenchTrench

03.05.b1

Ocean-Continent Convergent BoundaryOcean-Continent Convergent Boundary

Sketch ocean-continent convergence, labeling the Sketch ocean-continent convergence, labeling the processes in your own wordsprocesses in your own words

Oceanic plate subducted Oceanic plate subducted beneath continentbeneath continent

Oceanic and continental Oceanic and continental plate convergeplate converge

Overlying mantle Overlying mantle meltedmelted

Volcanoes and squeezing Volcanoes and squeezing form mountain beltform mountain belt

TrenchTrench

03.05.c1

Observe the distribution of volcanoes around the Pacific Ring Observe the distribution of volcanoes around the Pacific Ring of Fire of Fire

What doWhat doyou thinkyou thinkcould could explain explain the the overall overall pattern?pattern?

Pacific Ring of FirePacific Ring of Fire

03.05.c2

Subduction beneath Subduction beneath oceanic plates = island oceanic plates = island arcs (e.g., Japan)arcs (e.g., Japan)

Oceanic plates subducted Oceanic plates subducted on both sideson both sides

Subduction beneath continental Subduction beneath continental plates = mountain belts with plates = mountain belts with volcanoes (e.g., Andes)volcanoes (e.g., Andes)

Explain the Pacific Ring of Fire, including why Explain the Pacific Ring of Fire, including why the west and east sides are differentthe west and east sides are different

Spreading in East Spreading in East Pacific RisePacific Rise

03.05.d

Continent-Continent Continent-Continent ConvergenceConvergence

Subduction Subduction brings continents brings continents closercloser

Subduction Subduction of oceanic of oceanic part of platepart of plate

Continents Continents collidecollide

Two continents collideTwo continents collide

03.05.d3

Sketch a continental collision, labeling the Sketch a continental collision, labeling the processes in your own wordsprocesses in your own words

Pieces sliced offPieces sliced off

Continental collision = wide zone of deformationContinental collision = wide zone of deformation

Continental plate Continental plate buoyant, so buoyant, so subduction endssubduction ends

Few volcanoesFew volcanoes

Thick crust = high elevationThick crust = high elevation

03.06.a1

Transform BoundaryTransform Boundary

Observe how these two “plates” are moving Observe how these two “plates” are moving past each otherpast each other

Transforms Transforms link other link other types of plate types of plate boundariesboundaries

Plates move Plates move horizontally horizontally

past one past one another on another on

transform transform boundariesboundaries

Transforms link Transforms link spreading segments spreading segments in mid-ocean ridgesin mid-ocean ridges

03.06.a2

Observe the pattern of the Mid-Atlantic RidgeObserve the pattern of the Mid-Atlantic Ridge

Transforms link Transforms link spreading spreading segmentssegments

Spreading Spreading segmentssegments

Sketch a transform boundary, labeling the Sketch a transform boundary, labeling the processes in your own wordsprocesses in your own words

03.06.b1

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

03.07.a1

What Moves the Plates?What Moves the Plates?

Ridge pushRidge push

Slab pullSlab pull Other forces, such as Other forces, such as convection in mantleconvection in mantle

03.07.b1

Rates of Relative Plate MovementRates of Relative Plate Movement

Which plate boundaries have the fastest rates?Which plate boundaries have the fastest rates?

Some move faster than othersSome move faster than othersPlates move cm/yearPlates move cm/year

03.07.d1

Geometry of Plate BoundariesGeometry of Plate Boundaries

Observe how the motion of these two plates varies as the Observe how the motion of these two plates varies as the boundary changes orientationboundary changes orientation

Transform Transform boundaries link boundaries link other types of plate other types of plate boundaries, like two boundaries, like two spreading centers spreading centers or a spreading or a spreading center with a center with a subduction zonesubduction zone

As boundary changes As boundary changes orientation, plates orientation, plates move horizontally past move horizontally past one anotherone another

Spreading along Spreading along this orientation this orientation

03.07.d1

Geometry of Plate Boundaries IIGeometry of Plate Boundaries II

Observe how the motion between the North American and Observe how the motion between the North American and Pacific plates varies as the boundary changes orientationPacific plates varies as the boundary changes orientation

Transform boundary here Transform boundary here (Queen Charlotte fault), with (Queen Charlotte fault), with plates moving horizontally plates moving horizontally past one anotherpast one another

As boundary bends, As boundary bends, becomes convergent becomes convergent (Pacific plate subducted (Pacific plate subducted beneath NA)beneath NA)

03.08.a1

Sediment thickens away Sediment thickens away from ridge (had more from ridge (had more time to accumulate)time to accumulate)

Volcanic rocks in Volcanic rocks in crust youngest near crust youngest near ridge (just formed)ridge (just formed)

Test of Plate Tectonics Is Age of Seafloor Test of Plate Tectonics Is Age of Seafloor and Thickness of Sedimentand Thickness of Sediment

Drill Drill corescores

SedimentSediment

Volcanic rocksVolcanic rocks

Formation of Linear Island Formation of Linear Island and Seamount Chainsand Seamount Chains

Plate moves over a hot spotPlate moves over a hot spot

Lines of islands and Lines of islands and seamounts (e.g., Hawaii)seamounts (e.g., Hawaii)

Volcano Volcano forms over forms over a hot spota hot spot

Volcanoes become inactive as Volcanoes become inactive as area moves away from hot spotarea moves away from hot spot

Plate subsides Plate subsides as cools, so as cools, so islands become islands become seamountsseamounts

03.08.c

03.09.a1

Why is South America LopsidedWhy is South America LopsidedObserve the Observe the features features around South around South AmericaAmerica

Envision a Envision a cross section cross section from west of from west of

South South America America

to the Mid-to the Mid-Atlantic Atlantic

RidgeRidge

03.09.b1

Compare this cross section with the Compare this cross section with the one you envisionedone you envisioned

Eastern edge of Eastern edge of continent not a continent not a plate boundary plate boundary (passive margin)(passive margin)

Spreading along Spreading along mid-ocean ridgemid-ocean ridge

Subduction beneath Subduction beneath western edgewestern edge

Andes (mountains and Andes (mountains and volcanoes) over subduction volcanoes) over subduction zone, with trench offshorezone, with trench offshore

03.09.c

Evolution of Evolution of South AmericaSouth America

Observe the Observe the evolution of evolution of South America, South America, beginning with beginning with continental rifting continental rifting away from South away from South AmericaAmerica

Middle Middle MesozoicMesozoic(140 m.y ago)(140 m.y ago)

Late Late MesozoicMesozoic(100 m.y ago)(100 m.y ago)

PresentPresent

03.10.a1

Investigation: Where is the Safest Place to LiveInvestigation: Where is the Safest Place to Live

Identify possible plate boundaries in this area and indicate Identify possible plate boundaries in this area and indicate whether the boundary is divergent, convergent, or transformwhether the boundary is divergent, convergent, or transform

Continent Continent AA

Continent Continent BB

Identify where you would get earthquakes and volcanoes, Identify where you would get earthquakes and volcanoes, and then determine where it is safest to liveand then determine where it is safest to live

03.10.a

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