Plate TectonicsPlate TectonicsEarth layersEarth layers

History of plate tectonicsHistory of plate tectonics

Plate movement and marginsPlate movement and marginsPassive margins, spreading margins, Passive margins, spreading margins, and the Ring of Fireand the Ring of Fire

Ocean floor topography and plate tectonicsOcean floor topography and plate tectonics

Ocean floor effects: horizontal and vertical zonationsOcean floor effects: horizontal and vertical zonationsLifeLifeCirculationCirculation

CrustCrust4-60km4-60km

MantleMantle2885km2885km

Outer coreOuter core2270km2270km

Inner coreInner core1216km1216km

LithosphereLithosphere100km100km

AsthenosphereAsthenosphere250km250km

Lower mantleLower mantle25502550

Outer CoreOuter CoreInner coreInner core

Layers of the EarthLayers of the Earth

Earth topographyEarth topography

Movement of Movement of ContinentsContinents

Old views: Geosyncline cycleOld views: Geosyncline cycleno continent movementno continent movement

Instead, continent growth through sediment accretionInstead, continent growth through sediment accretion

Movement of Movement of ContinentsContinents

Alfred Wegener: Plate Tectonics: 1912Alfred Wegener: Plate Tectonics: 1912Continents like “puzzle pieces”Continents like “puzzle pieces”Fossils on different continentsFossils on different continents

Carey and the Southern Hemisphere geologistsCarey and the Southern Hemisphere geologists

Movement of Movement of ContinentsContinents

Morey: CanadaMorey: CanadaHess: mantle convection and sea floor spreadingHess: mantle convection and sea floor spreadingContinental Drift: theoryContinental Drift: theory

Movement of Movement of ContinentsContinents

Vine and Matthews: tested Continental DriftVine and Matthews: tested Continental DriftMagnetic “stripes” Magnetic “stripes” Magnetic reversalsMagnetic reversalsSymmetrial Symmetrial

Theory of Plate tectonics accepted.Theory of Plate tectonics accepted.

IstostacyIstostacyDensity differencesDensity differences

Density: closeness of moleculesDensity: closeness of moleculesMass/volumeMass/volume

Istostacy: Crustal floatation on the mantleIstostacy: Crustal floatation on the mantleLike ice cube: Like ice cube:

part above the mantle surface part above the mantle surface part beneathpart beneath

““Root” balances “top”: floats in equilibriumRoot” balances “top”: floats in equilibrium

Ocean crust more dense, floats lowerOcean crust more dense, floats lower

Plate Movement: Cross Plate Movement: Cross SectionSection

Active MarginActive MarginDivergent Plate BoundariesDivergent Plate Boundaries

Crustal formation, spreadingCrustal formation, spreading

Mid-ocean ridgesMid-ocean ridgesmantle convection upwardmantle convection upwardvolcanismvolcanismnew crust madenew crust madeBegin in continentBegin in continent

Africa/South AmericaAfrica/South AmericaAfrican rift valleyAfrican rift valley

Volcanoes, earthquakesVolcanoes, earthquakes

African Rift Valley

Gondwana

RiftingRifting

Active MarginActive MarginConvergent Convergent

PlatePlate Boundaries Boundaries

Subduction: destructiveSubduction: destructive

Ocean - oceanOcean - oceanIsland arcIsland arcJapanJapan

Ocean-continentContinent-continent

Volcanoes, earthquakes, Volcanoes, earthquakes, trenchestrenches

Active MarginActive MarginConvergent Convergent

PlatePlate Boundaries Boundaries

Subduction: destructiveSubduction: destructive

Ocean - oceanContinent - oceanContinent - ocean

Volcanic arcVolcanic arcAndes, CascadesAndes, Cascades

Continent - continent

Volcanoes, earthquakes, trenchesVolcanoes, earthquakes, trenches

Active MarginActive MarginConvergent Convergent

PlatePlate Boundaries Boundaries

Subduction: destructiveSubduction: destructive

Ocean - oceanContinent - oceanContinent - continent: Continent - continent:

tall mountainstall mountainsTibetan plateauTibetan plateau

Volcanoes, earthquakes, trenchesVolcanoes, earthquakes, trenches

Neither Neither constructive constructive nor destructivenor destructive

Strike-slip,Strike-slip, shear: shear: 2 plates slide 2 plates slide San AndreasSan Andreas

Earthquakes Earthquakes no volcanoesno volcanoes

Active Margins: Transform Active Margins: Transform BoundariesBoundaries

Passive MarginsPassive Margins

Stable marginsStable margins

Development of wide Development of wide continental shelfcontinental shelf or or rampramp

East coast North AmericaEast coast North America

Mountains from previous Mountains from previous continent-continent collisionscontinent-continent collisions

Small earthquakes from ancient Small earthquakes from ancient faultsfaultsBut no effects from marginBut no effects from margin

Hot SpotsHot SpotsMantle plumes: “stationary” as Mantle plumes: “stationary” as plates move over themplates move over themRecord of plate movementRecord of plate movement

Land or oceanLand or oceanLand: YellowstoneLand: YellowstoneOcean: island formationOcean: island formation

HawaiiHawaii

Hot SpotsHot Spots

Superplumes in Cretaceous: Superplumes in Cretaceous: High rates of sea floor spreading:High rates of sea floor spreading:Ocean crust warm --> sea level much higherOcean crust warm --> sea level much higher

Sundance SeaSundance SeaCO2 into atmosphere: greenhouse effectCO2 into atmosphere: greenhouse effect

Ocean DepthsOcean Depths

Ocean DepthsOcean DepthsSupralittoral zone: “spray Supralittoral zone: “spray zone”: zone”: terrestrialterrestrialLittoral zone: tidal rangeLittoral zone: tidal rangeSublittoral zoneSublittoral zone

Inner sublittoral zone: 0-Inner sublittoral zone: 0-50m50m

Outer sublittoral Outer sublittoral zone:50-zone:50- 200m200mBathyal zone: 50m - 4kmBathyal zone: 50m - 4kmAbyssal zone: 4km - 6kmAbyssal zone: 4km - 6kmHadal zone: 6km + (deepest: Hadal zone: 6km + (deepest: Mariana Trench: 11km)Mariana Trench: 11km)

Provinces: shallowProvinces: shallowContinental shelfContinental shelf

Wide: passive margins; narrow: active marginsWide: passive margins; narrow: active marginsShelf break ~135m, but wide rangeShelf break ~135m, but wide range

Continental slope:Continental slope:Submarine canyonsSubmarine canyonsTurbidity currentsTurbidity currents

Continental Rise: Continental Rise: deep sea fansdeep sea fans

Provinces: DeepProvinces: DeepAbyssal plainAbyssal plain

>4km>4kmOcean ridges, topography on plainOcean ridges, topography on plainSeamounts, guyots: other volcanic activitySeamounts, guyots: other volcanic activityTrenches >6.7kmTrenches >6.7km

D L WJapan Trench 10.5 2200 120Mariana Trench 11.0 2550 70Philippine Trench 10.8 1400 55Aleutian Trench 7.7 3700 50Peru-Chile Trench 8.1 5900 100Puerto Rico Trench 8.4 1550 120Java Trench 7.5 4500 80

Horizontal zonation: Horizontal zonation: Geographic rangeGeographic rangeProximity to resourcesProximity to resourcesLatitude (Temperature)Latitude (Temperature)Circulation patternsCirculation patternsSalinitySalinity

Vertical zonation (water column)Vertical zonation (water column)ResourcesResourcesPressurePressureTemperatureTemperatureLightLight Water ChemistryWater Chemistry

Geographic range + vertical zonationGeographic range + vertical zonationResources, life history, habitat constraints determineResources, life history, habitat constraints determine

Life in the oceanLife in the ocean