This document discusses plate tectonics and the theory of plate tectonics. It provides information on key aspects of plate tectonics including: - The lithosphere is broken into individual plates that move over the asthenosphere in response to convection currents. - Plate boundaries are sites of geologic activity including divergent boundaries which create oceanic crust, transform boundaries, and convergent boundaries involving subduction or collision which alter crust composition. - Mantle convection provides the primary driving force for plate tectonics, with slab pull and ridge push contributing to plate motions.

1. Modul 2Modul 2
Plate TectonicsPlate Tectonics
THE NEW GLOBALTHE NEW GLOBAL
TECTONICTECTONIC

2. PLATE TECTONICSPLATE TECTONICS
Continental driftContinental drift
 The theory that the continents have moved inThe theory that the continents have moved in
relation to one anotherrelation to one another
Plate tectonicsPlate tectonics
 The theory of global dynamics in which theThe theory of global dynamics in which the
lithosphere is believed to be broken intolithosphere is believed to be broken into
individual plates that move in response toindividual plates that move in response to
convection in the (upper) mantle. The margins ofconvection in the (upper) mantle. The margins of
the plates are sites of considerable geologicthe plates are sites of considerable geologic
activity.activity.

3. Crust Mantle Core (CMC)-sphere

4. Crust Mantle Core (CMC)-sphere

5. Depth(km)
cold, rigid, brittle
hot, plastic
Δ = 3,3– 4,3 g/cm3
hot, high pressure,
rigid, brittle
Liquid
45000
C
solid
rocks
ultrabasic
igneous rocks
(MgO, SiO2)
Fe, Ni
Crust Mantle Core (CMC)-sphere

6. Plate Tectonic TheoryPlate Tectonic Theory
• Lithosphere is broken into individual piecesLithosphere is broken into individual pieces
calledcalled platesplates
• Plates move over the asthenospherePlates move over the asthenosphere
– as a result of underlyingas a result of underlying convection cellsconvection cells

7. Antonio Snider-Pelligrini’ Map (1858)Antonio Snider-Pelligrini’ Map (1858)
Continental DriftContinental Drift

8. Alfred Wegener’ Map (1915)Alfred Wegener’ Map (1915)
Continental DriftContinental Drift

9. Wegener’s Concept of Continental Drift and OrogenesisWegener’s Concept of Continental Drift and Orogenesis
Note:Note:
Most geologists and geophysicists rejected Wegener’s ideasMost geologists and geophysicists rejected Wegener’s ideas
because they violated what was known about thebecause they violated what was known about the STRENGTHSTRENGTH
OF ROCKSOF ROCKS..
Also, centrifugal force (from Earth’s rotation) along with tidalAlso, centrifugal force (from Earth’s rotation) along with tidal
forcesforces were deemed to bewere deemed to be TOO SMALLTOO SMALL to move the continents!to move the continents!
Continental DriftContinental Drift

10. Continents FitContinents Fit
TogetherTogether
Evidence on ContinentEvidence on Continent
Best fit at 100 m below sea levelBest fit at 100 m below sea level

11. Evidence on ContinentEvidence on Continent
Rocks andRocks and
Structures Match UpStructures Match Up

12. Evidence on ContinentEvidence on Continent

13. AppalachiansAppalachians
AppalachiansAppalachians
Caledonides
Mauritanides
Mountain Belts ofMountain Belts of
the Same Agethe Same Age
Evidence on ContinentEvidence on Continent

14. Evidence on ContinentEvidence on Continent
Glacial FeaturesGlacial Features
Direction of ice flowDirection of ice flow

15. Evidence on ContinentEvidence on Continent
FossilsFossils
LystrosaurusLystrosaurus
GlossopterisGlossopteris
CynognathusCynognathus
MesosaurusMesosaurus
Permian-PennsylvanianPermian-Pennsylvanian
Early TriassicEarly Triassic
PermianPermian

16. Evidence on ContinentEvidence on Continent
PaleoclimatePaleoclimate
of Pangeaof Pangea

17. Evidence on SeafloorEvidence on Seafloor
SeafloorSeafloor
MorphologyMorphology

18. Evidence on SeafloorEvidence on Seafloor
Paleomagnetism andPaleomagnetism and
seafloor spreadingseafloor spreading
Magnetic Time ScaleMagnetic Time Scale Magnetic Stripe Formation at Ridge CrestMagnetic Stripe Formation at Ridge Crest

19. Evidence on SeafloorEvidence on Seafloor
Paleomagnetism andPaleomagnetism and
seafloor spreadingseafloor spreading

20. Evidence on SeafloorEvidence on Seafloor
Seafloor Age MapSeafloor Age Map

21. Mantle Plume Hot Spot TracksMantle Plume Hot Spot Tracks
Evidence on SeafloorEvidence on Seafloor

22. ReconstructionReconstruction

23. MODUL 03
GERAK DAN SIFAT
INTERAKSI

24. Directions of Motion and Plate Velocities Determined byDirections of Motion and Plate Velocities Determined by
Mantle Plume Hot Spot Tracks and Age-Dating of RocksMantle Plume Hot Spot Tracks and Age-Dating of Rocks
Plate TectonicsPlate Tectonics

25. Directions of Motion and Plate Velocities Determined by GPSDirections of Motion and Plate Velocities Determined by GPS
(Global Positioning System) Satellites(Global Positioning System) Satellites
Plate TectonicsPlate Tectonics
Directions of Motion and Plate Velocities DeterminedDirections of Motion and Plate Velocities Determined
by GPS (Global Positioning System) Satellitesby GPS (Global Positioning System) Satellites

26. Earth’s Tectonic PlatesEarth’s Tectonic Plates
North American
South
American
Juan de
Fuca
Cocos
Pacific
Nazca
Antarctic Antarctic
Caribbean
Scotian
African
Eurasian
Arabian
Indo
Australian
Pacific
Philippine
North
American
Plate TectonicsPlate Tectonics

27. Plate TectonicsPlate Tectonics
What drivesWhat drives
Plate Tectonics???Plate Tectonics???

28. What drives plate motions
• Forces that drive plate
motion
– Slab-pull
• Cold, dense slabs of
subducted oceanic
lithosphere pull the plate
towards the subduction zone
– Ridge-push
• The higher elevation of
spreading centers result in
oceanic lithosphere wanting
to move “downhill”, away
from the ridge
• Far less important than
slab-pull
– Mantle drag and plate
resistance
• Can act to increase or
decrease plate motion

29. Mantle convection provides
the primary drive for
plate tectonics

31. What drives plate motions
• Models of plate-mantle
convection
• Any model must be consistent
with observed physical and
chemical properties of the
mantle
• Horizontal movement of
plates causes mantle
upwelling
• Models
– Layering at 660 km
– Explains why basalts
erupted at mid-ocean
ridges are different (more
evolved, relatively shallow
source) compared to those
erupted at hot-spots
(more primitive, deeper
source).
– We know that subducting
slabs descend beneath 660

32. What drives plate motions
• Whole-mantle convection
– Would mix the entire
mantle in the space of a
few hundred million
years, removing
heterogeneities

33. What drives plate motions
• Deep-layer model
– “Lava lamp model”
– Two layers swell and
shrink in a complex
fashion in response to
heat from the Earth’s
interior

34. Internal HeatInternal Heat
Plate TectonicsPlate Tectonics

35. Arc-Trench systems 35

36. Arc-Trench systems 36
Trench roll-back

37. Arc-Trench systems 37
Types of arc-trench system

38. Results in the formation of Oceanic CrustResults in the formation of Oceanic Crust
Plate TectonicsPlate Tectonics
Divergent BoundaryDivergent Boundary

39. Transform BoundaryTransform Boundary
Plate TectonicsPlate Tectonics

40. Results in the formation & growth of Continental CrustResults in the formation & growth of Continental Crust
and destruction of Oceanic Crustand destruction of Oceanic Crust
Melting
Produces
More
Felsic
Magma
Plate TectonicsPlate Tectonics
Convergent Boundary: SubductionConvergent Boundary: Subduction

41. Results in the growth of Continental CrustResults in the growth of Continental Crust
Convergent Boundary: CollisionConvergent Boundary: Collision
Plate TectonicsPlate Tectonics

42. BASIC PLATE TECTONICS – RevisedBASIC PLATE TECTONICS – Revised
• Earth’s lithosphere is broken into 12-24Earth’s lithosphere is broken into 12-24
rigid platesrigid plates
• Plates move about 1-10 cm/yr on the plasticPlates move about 1-10 cm/yr on the plastic
AsthenosphereAsthenosphere
• ““Geology happens” where the platesGeology happens” where the plates
interact with one another along Divergent,interact with one another along Divergent,
Transform, Subduction and CollisionalTransform, Subduction and Collisional
BoundariesBoundaries