What’s inside the earth


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What’s inside the earth

  1. 1. What’s inside the Earth?What’s inside the Earth?Is there really another world atIs there really another world atthe center?the center?What is theWhat is theenergy for surfaceenergy for surfacefeatures?features?
  2. 2. Our Dynamic EarthOur Dynamic Earth Earth is constantly changingEarth is constantly changing How do we know it’s dynamic??How do we know it’s dynamic?? Earthquakes (and tsunamis)Earthquakes (and tsunamis) Volcanic eruptionsVolcanic eruptions Surface Features:Surface Features:– Mountain Ranges; Mid-OceanMountain Ranges; Mid-OceanRidges; Deep-Sea TrenchesRidges; Deep-Sea Trenches
  3. 3. Topography of the Ocean FloorTopography of the Ocean Floor
  4. 4. Mid-OceanRidgeTopography of the Ocean FloorTopography of the Ocean Floor
  5. 5. Mid-OceanRidgeDeep-seaTrenchTopography of the Ocean FloorTopography of the Ocean Floor
  6. 6. Mid-OceanRidgeDeep-seaTrenchTopography of the Ocean FloorTopography of the Ocean FloorIslandChain
  7. 7. ElevatedContinents
  8. 8. ElevatedContinentsSubmergedOcean Basins
  9. 9. Questions:How are the ocean basins formed?How permanent are these features?What is the age of the ocean floor?What’s the age of the continents?Why are the ocean basins deep andthe continents high?
  10. 10. The Surface of the EarthThe Surface of the Earth 2 levels:2 levels:– elevatedelevated continentscontinents– submergedsubmerged ocean basinsocean basins What causes these surface features?What causes these surface features? We must know what goes onWe must know what goes on insideinside the Earththe Earth
  11. 11. What’s going on inside theWhat’s going on inside theEarth?Earth?
  12. 12. Early IdeasEarly Ideas Jules VerneJules Verne
  13. 13. ““Journey toJourney tothe Center ofthe Center ofthe Earth”the Earth” Entered in IcelandEntered in Iceland Exited in ItalyExited in Italy
  14. 14. Information about the Earth’sInformation about the Earth’sInterior comes from:Interior comes from: MeteoritesMeteorites VolcanoesVolcanoes Seismic Waves (“sound images”)Seismic Waves (“sound images”) TremendousTremendous pressurepressureenormousenormous heat (from naturalheat (from naturalradioactivity)radioactivity)
  15. 15. Meteor Crater (Arizona)Meteor Crater (Arizona)
  16. 16. Willamette MeteoriteWillamette Meteorite Found 1902,Found 1902,in West Linnin West Linn Largest inLargest inthe U.S.A.the U.S.A. Sold and nowSold and nowresides inresides inNYCNYC
  17. 17. VolcanoesVolcanoes E.g., Hawaiian “hotspot”E.g., Hawaiian “hotspot” Windows into theWindows into theEarthEarth Samples 200km downSamples 200km down(e.g., diamonds!)(e.g., diamonds!)
  18. 18. Seismic WavesSeismic Waves Sound energySound energyfrom earthquakesfrom earthquakesand largeand largeexplosionsexplosions
  19. 19. DEPTHSDEPTHS Top of MantleTop of Mantle– 10 to 70 km (5 to 3010 to 70 km (5 to 30miles)miles) Top of CoreTop of Core– 2,900 km (20002,900 km (2000miles)miles) Center of EarthCenter of Earth– 6,300 km (4,0006,300 km (4,000miles)miles) Mt. EverestMt. Everest ≈≈ 9 km9 kmhigh.high. Marianas TrenchMarianas Trench ≈≈ 1111km deep.km deep.
  20. 20. How do we know what’s insideHow do we know what’s insidethe Earth?the Earth?
  21. 21. How do we know what’s inside the Earth?How do we know what’s inside the Earth?Direct ObservationsDirect Observations:: Exposures on surfaceExposures on surface upupfromfrom ≈≈ 50 km (30 miles)50 km (30 miles)depthdepth DrillingDrilling toto ≈≈ 15 km (1015 km (10miles)miles) Volcanic MaterialVolcanic Material upupfromfrom ≈≈ 200 km (120200 km (120miles) depthmiles) depth
  22. 22. How do we know what’s insideHow do we know what’s insidethe Earth?the Earth?
  23. 23. How do we know what’s insideHow do we know what’s insidethe Earth?the Earth?Indirect ObservationsIndirect Observations:: Magnetic FieldMagnetic Field Iron core.Iron core. Gravity FieldGravity Field Densities:Densities:– Crust: 2 - 3 g/cmCrust: 2 - 3 g/cm33– Mantle: 3.3 - 5.8g/cmMantle: 3.3 - 5.8g/cm33– Core: 10.8 g/cmCore: 10.8 g/cm33 Earthquake Seismic WavesEarthquake Seismic Waves Physical statePhysical state of crust,of crust,mantle, core.mantle, core.
  24. 24.  LITHOSPHERELITHOSPHERE– rigidrigid outer shellouter shell– crust and upper mantle (~ 50 to 200 kmcrust and upper mantle (~ 50 to 200 kmthick)thick)– somewhat brittle, breakablesomewhat brittle, breakable– cold (likecold (like butterbutter out of fridge)out of fridge) ASTHENOSPHEREASTHENOSPHERE– warmer,warmer, plasticplastic layer under lithospherelayer under lithosphere– mantle from ~ 150 to 700 kmmantle from ~ 150 to 700 km– squishy, plasticsquishy, plastic– warm (likewarm (like softened buttersoftened butter)) LOWER MANTLELOWER MANTLE– Solid,Solid, but can flow over time!but can flow over time!– ~700 to 2900 km~700 to 2900 km OUTER COREOUTER CORE– liquidliquid INNER COREINNER CORE– solidsolidInterior of Earth by StrengthInterior of Earth by Strength
  25. 25. ElevatedContinentsSubmergedOcean Basins
  26. 26. Swimming Pool
  27. 27. Earth’s Mantle
  28. 28. ContinentalCrustEarth’s Mantle
  29. 29. Types of CrustTypes of Crust Continental CrustContinental Crust– 20 to 70 km (10 to 30 miles) thick.20 to 70 km (10 to 30 miles) thick.– Composed of highly evolved rocks,Composed of highly evolved rocks,like granite (igneous), andlike granite (igneous), andmetamorphic rocks, squeezed andmetamorphic rocks, squeezed andheated under mountain rangesheated under mountain ranges
  30. 30. ContinentalCrustEarth’s Mantle
  31. 31. Oceanic Crust
  32. 32. Types of CrustTypes of Crust Continental CrustContinental Crust– It is less dense, but thicker than oceanicIt is less dense, but thicker than oceaniccrustcrust Oceanic CrustOceanic Crust– It is thinner, but more dense thanIt is thinner, but more dense thancontinental crust, so it sits lower thancontinental crust, so it sits lower thancontinental crust.continental crust.– Composed of basalt (volcanic).Composed of basalt (volcanic).
  33. 33. Thick, BuoyantContinental Crust
  34. 34. Thin, Less-BuoyantOceanic Crust
  35. 35. Thick Continental Crust Floats Higher
  36. 36. Thick Continental Crust Floats HigherThin Oceanic Crust Floats Lower
  37. 37. Mid-AtlanticRidge
  38. 38. Water Fills inthe Low Areas
  39. 39. And HidesFeatures on theOcean Floor!Water Fills inthe Low Areas
  41. 41. PLATE TECTONICSPLATE TECTONICS TectonicsTectonics:: From the Greek “From the Greek “tectontecton”” builderbuilder ““architect”architect” The study ofThe study of large featureslarge features on Earth’son Earth’ssurface and thesurface and the processesprocesses that formedthat formedthem.them.
  42. 42.  LargeLarge featuresfeatures::– continents, mountain rangescontinents, mountain ranges– ocean basinsocean basins andand processesprocesses::– earthquakesearthquakes– volcanic eruptionsvolcanic eruptions These are due to movement of plates ofThese are due to movement of plates ofEarth’s outer shell.Earth’s outer shell. All resulting fromAll resulting from mantle convectionmantle convectionPLATE TECTONICSPLATE TECTONICS::
  43. 43. Cracked Egg Shell!