Plate Tectonics - 2 - Lamont–Doherty Earth Observatory
EESC 2200The Solid Earth SystemPlate tectonics - 215 Sep 08Subduction ZonesTransform Faults
CompositionalLayering (Chemical)ReviewCrust6-70kmMantle2885The Nectarine!Core6370ES 101-Lect 2
Compositional Layeringvs.Mechanical LayeringHow Strong or Weak?Temperature weakensPressure strengthensBOTH Increase into the EarthES 101-Lect 2
GeothermTemperature CDepthkmCoreMantleIron meltsOuter coreIron solidInner coreES 101-Lect 2
Mechanical Layering29005150Liquid Outer Core(magnetic field)Solid Inner Core6370 kmES 101-Lect 2
Temperature ( C)0Depth (km)LithospherehL 90 kmAsthenosphereTurcotte & Schubert, 20026001300
GeothermTemperatureCrust ColdMantle andStrong CLithosphereHot and WeakAsthenosphereDepthkmES 101-Lect 2
Mechanical LayeringLithosphereThe "Plate"0-250 kmdependingon ageCrust some mantleStrong, rigid shell -"floats"ES 101-Lect 2
Mechanical LayeringAsthenosphereThe asthenosphereis mostly solid,but it flows atGeologicaltime scales (Ma)SILLY PUTTYES 101-Lect 2
Convection inMantle/Asthenosphere-- The driving force for movement atEarth's Surface- Plate TectonicsBecause Mantle is HOT!DensityES 101-Lect 2
Why is the Earth Hot?ES 101-Lect 2
Why is the Earth’s Interior Hot?RadioactivityOriginal heat (gravitational)
Consequences of a Hot Earth Dense material sinks, light floatDIFFERENTIATION Some parts weak -- flowCONVECTIONES 101-Lect 2
Consequence of Convection.Plate TectonicsLarge plates move overthe Earth surfaceRates: 5 - 120 mm/yrES 101-Lect 2
ES 101-Lect 2
At Boundaries, Plates.1. DivergentSpread Apart2. ConvergentCollide3. TransformSlide byAnimationsES101-Lect 2B
At Boundaries, Plates. DivergentMiddle of Atlantic ConvergentAleutians TranformSan Andreas FaultES101-Lect 2B
DivergentMid-Ocean RidgeES101-Lect 2B
DivergentMid-Ocean RidgeES101-Lect 2B
DivergentMid-Ocean RidgeES101-Lect 2B
Mantle Melting1100 C 1300 CPartialMeltingTemperatureAllLiqDepthAll SolidES101-Lect9
Mantle Melting1100 C 1300 CPartialMeltingTemperatureAllLiqDepthAll SolidRaiseTemp?ES101-Lect9
Mantle Melting1100 C 1300 CPartialMeltingTemperatureAllLiqDepthAll SolidLowerPressure!!ES101-Lect9
Ridges:plate spreadingmantle below?1300 CES101-Lect9
Ridges:1300 CES101-Lect9
Ridges:Mantle undergoes decompression melting--- Basalts (dry)1300 Cbasalt mantle melt ("blood of the Earth")ES101-Lect9
Continental Break-UpAfricaSouthAmerica140-110 MaLate Jur-Early CretES101-Lect 2B
Continental Break-UpAfricaSouthAmericaES101-Lect 2B
Continental Break-UpAfricaSouthAmericaES101-Lect 2B
Ocean Crustal Age Oceanic crust spreads away from the ridge axis. Newcrust is closer to the ridge; older crust farther away. Oldest oceanic crust is found at the far edge of the basin.Earth: Portrait of a Planet, 3rd edition, by Stephen MarshakChapter 4: The Way the Earth Works: Plate Tectonics
5000 km0 MaDepth-AgeRelationshipIf you know the age of a patch of seafloor, you can predict its depth toamazing accuracy!200Ma2500Depth (m)200Ma60009361000155Sqr Rt Age (M.y.)
Drilling SedimentaryInput to Subduction Zones
Sediment &OceanicCrust Cores
ODP Leg 185Drilling oldestcrust in Pacific
Anatahan, Marianas2004
mid-oceanridgetrenchsubductionzoneES101-Lect 2B
Fate of Subducted Plates?Plate descent continues past the earthquake limit. The lower mantle may be a “plate graveyard.” Earth: Portrait of a Planet, 3rd edition, by Stephen MarshakChapter 4: The Way the Earth Works: Plate Tectonics
ConvergentSubductiondowngoing plateupperplateES101-Lect 2B
Subduction ZonesUpper plate like "bulldozer" scraping sedimentsaccretionarywedgeupperplateES101-Lect 3
Convergent Boundaries Accretionary prisms – Deformed sediment wedges. Sedimentsscraped off subducting plates are smearedand welded onto the overriding plates. These contorted sediments can be pushed above sea. Washington’s Olympic Peninsula. Taiwan.Earth: Portrait of a Planet, 3rd edition, by Stephen MarshakChapter 4: The Way the Earth Works: Plate Tectonics
Subduction ZonesEarthquakes!upperplateES101-Lect 3
Subduction ZonesEarthquakes!downgoing plateupperplateES101-Lect 2B
SumatraJava15010050 kmWadati-Benioff ZoneearthquakesSyracuse & Abers (2006) G3Earthquakes defineSubducting plate surface
Aftershocks of Sumatra Dec 2004Fig. 2. Map showing aftershock locations for the first 13weeks after the 26 December 2004 earthquake from theNEIC (yellow dots, with radii proportional to seismicmagnitude). Moment-tensor solutions from the HarvardCMT catalog (21) are shown for the 26 December 2004and 28 March 2005 mainshocks (large solutions atbottom, with associated centroid locations) andaftershocks. Star indicates the epicenter for the 2004rupture obtained by the NEIC. Dashed line shows theboundary between the aftershock zones for the twoevents.Lay et al, Science (2005)
Subduction Volcanism100kmES101-Lect 2B
Most subduction zones are arcuate on mapstrenchvolcanoesGeoff's arc - 2Volcanic ArcsES101-Lect 2B
H2O -- Lowers Melting Point800 C1100 CT"Dry"MeltDepthAll SolidyouarehereES101-Lect9
H2O -- Lowers Melting Point800 C1100 CTDepthWetmeltingyouarehereES101-Lect9
Two Ways that the Mantle Melts: Decompression Water AddedHow do we decompress and addwater to the mantle? ridges subduction zones hot spotsES101-Lect9
Subduction Zones:mantle flow?ES101-Lect9
Subduction Zones:At sea, top of plate reacts with water.ES101-Lect9
wet crust subductswarms,sweats out water.ES101-Lect9
water -- mantle wedge,-- basalt arc volcanism.ES101-Lect9
Aleutian ArcAnchoragewhich way?ES101-Lect 2B
Aleutian ArcAnchoragewhat happens when subduct a continent?ES101-Lect 2B
Oceanic plates subductContinental plates usually do notAffects geologic record -how?ES101-Lect 2B
Convergent Boundaries Subduction Zonerequires an oceanic plate to subductAleutians Continent-Continent-Collisiontwo continental platesHimalayasES101-Lect 2B
Review:Fracture zoneTransformFault
Transform Boundaries Oceanic transforms – Offsets along the MOR. Olderinterpretation – Faulting occurs after MOR forms. Moderninterpretation – Faulting occurs with the MOR.Earth: Portrait of a Planet, 3rd edition, by Stephen MarshakChapter 4: The Way the Earth Works: Plate Tectonics
Transform Boundaries Continental transforms – Chop continental crust. Example:The San Andreas Fault.Earth: Portrait of a Planet, 3rd edition, by Stephen MarshakChapter 4: The Way the Earth Works: Plate Tectonics
Transform San Andreas Fault Big Earthquakes,No Volcanoes OffsetsES101-Lect 2B
Transform San Andreas Faultright lateral Big Earthquakes,No Volcanoes Offsetsslides-generalES101-Lect 2B
1. Earthquakes occur on astatistically-predictable cycle
SAF 35 mm/yearPacific-N. American50 mm/year
1906 EarthquakeMagnitude 7.86 metersof slip on afault 500 kmlong
earthquake cycleFault at boundary between plates is “locked”Stress builds up on fault as plates moveStress exceeds strength of faultFault suddenly slips in an earthquakePlate boundary movesFault locks again
faultfault lockedloadingmore loadingEarthquake !
Earthquake Repeat TimeMean time interval betweenlarge earthquakes on aparticular faultFor San Andread6 meters 6000 mm6000 mm / 35 mm/year 170 years170 years of plate motionwas released by thisearthquakeBasis for believing thatThe repeat time forSuch earthquakes isAbout 200 years.
Scientific basisfor earthquakeriskassessments
Aftershocks of Sumatra Dec 2004Fig. 2. Map showing aftershock locations for the first 13weeks after the 26 December 2004 earthquake from theNEIC (yellow dots, with radii proportional to seismicmagnitude). Moment-tensor solutions from the HarvardCMT catalog (21) are shown for the 26 December 2004and 28 March 2005 mainshocks (large solutions atbottom, with associated centroid locations) andaftershocks. Star indicates the epicenter for the 2004rupture obtained by the NEIC. Dashed line shows theboundary between the aftershock zones for the twoevents.Lay et al, Science (2005)
Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 4: The Way the Earth Works: Plate Tectonics Ocean Crustal Age Oceanic crust spreads away from the ridge axis. New crust is closer to the ridge; older crust farther away. Oldest oceanic crust is found at the far edge of the basin.
Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 4: The Way the Earth Works: Plate Tectonics Locations on Earth where tectonic plates meet. Identified by concentrations of earthquakes. Associated with many other dynamic phenomena. Plate interiors are almost earthquake-free. Plate Boundaries
Deceased members of the Cullen Family Philip Cullen, Jr. Philip Cullen, Sr. Dalton Family Davis Family Deceased members of the DeFelice Family Jacquelyn Delaporta Michael DiGiantommaso DiPasquale Family Al and Peg DiSalvo Barbara Doherty Daniel Doherty Diana Doherty Thomas and Matilda Doherty William and Fran
Aug 26, 2015 · Continental Drift, Sea Floor Spreading and Plate Tectonics Plate Tectonics is a theory developed in the late 1960s, to explain how the outer layers of the Earth move and deform. The theory has caused a revolution in the way we think about the Earth. Since the development of the theory, ge
The physical theory of plate tectonics thus has important applications to planetary habitability and the origins of life in the universe (e.g., Korenaga 2012). However, if we do not have a theory to explain why plate tectonics initiated on Earth and how it evolved with time, we cannot apply our understanding to other planets under
CVR Odometer and Plate Type Updates - EVR Policies . Plate Types . Plate Type . Plate Types. There are select plates that can now be issued as a new plate through EVR. Just like it works for special plates on EVR, these plate types will go through the . Centralized Plate Distribution Process. You will select the plate type during a New Plate .
Plate Tectonics. Use the following link to find these answers: . an oceanic plate collides with a continental plate. Oceanic crust tends to be _ and _ than continental crust, so the denser . Part V. Questions you should be able to answer now that you completed this webquest. Note - you may go back to the website and review to assist .
Lesson Plan Lesson Preparation Review the Science Background provided in the Unit Overview. Review and make copies of Student Reading Plate Tectonics Diagrams and Student Worksheet Plate Tectonic Drawings, one per student. Preview PowerPoint Tectonic Plate Boundaries and make arrangements to project it. Preview video clips from the College of Exploration on Plate Tectonics and .
transactions: (i) the exchange of the APX share for EPEX spot shares, which were then contributed by the Issuer to HGRT; (ii) the sale of 6.2% stake in HGRT to RTE and (iii) the sale of 1% to APG. The final result is that the Issuer has a participation in HGRT of 19%. For information regarding transactions (i) and (ii) please refer to the press release dated 28 August 2015 (in the note 4 pp .
