Structure and Plate Tectonics

Июль 24, 2022

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Structure and Plate Tectonics

Содержание

2. 4- Deformation of Rocks A force causes stress on rocks Rocks near surface are elastic and
3. Three Types of Stress 4- Compression – pushes on rocks from opposite directions; shortens rocks Tension
4. 4- Earth’s Interior Internal heat source is energy causing metamorphism, uplift of crust (rock cycle) Seismic
5. 4- Earth’s Structure
6. 4- Earth’s Structure Crust – Less dense layer Lithosphere Mantle ~2,900 km (1,800 mi) thick Rocky,
7. Earth’s Interior Scientists hypothesize inner and outer core are iron-nickel alloy Outer core Metallic liquid Inner
8. 4- Earth’s Magnetic Field Inner core is solid, rotates faster than planet Electrically charged metallic ions
9. 4- Earth’s Magnetic Field
10. 4- Earth’s Internal Heat Geothermal gradient 25°C/km – temperature increases with depth Heat from radioactive decay
11. Earth’s Internal Heat 4-
12. 4- Continental Drift Idea that continents were once joined first proposed in 1596 by Dutch mapmaker
13. Continental Drift Alfred Wegener 1922 book on theory of continental drift More evidence than Taylor –
14. 4- Developing Theory of Plate Tectonics
15. 4- Developing Theory of Plate Tectonics Mapping ocean floor began in 1855 by U.S. Navy WW1
16. Mapping the Ocean Floor 4-
17. Magnetic Studies Igneous basalts contain iron mineral magnetite (Fe3O4) Magnetite is naturally magnetic Atoms orient parallel
18. Magnetic Reversal Figure 4.11 Page 101
19. Sea Floor Spreading Figure 4.12, Page 101 Mid oceanic ridges – magma erupts forming new ocean
20. Earthquakes Earthquake – release of energy that occurs when rocks are deformed past their elastic limit
21. Earthquake Locations Figure 4.13, Page 102
22. Earthquake Locations Epicenters along Mid Atlantic Ridge – magma rises up, buckles crust forming ridge Epicenters
23. Last Piece of Evidence for Continental Drift Magnetite rocks form/cool, atoms orient to magnetic north pole
24. Polar Wandering 4-
25. 4- Plate Tectonics and Earth’s Systems By 1960, 50 years of data proved sea floor spreading
26. Plate Tectonics and Earth’s Systems Plate Boundaries defined by epicenters Plates move over asthenosphere Slide past
27. 4- Plates
28. Plate Boundaries Movement generates compression, tension or shear 3 Types of Boundaries Divergent Convergent Transform See
29. 4- Plate Boundaries
30. 4- Movement of Plates Figure 4.17, Page 106
31. Surface Features & Plate Boundaries Convergent Oceanic-oceanic island arc; one plates undergoes subduction; may produce an
32. 4- Surface Features & Plate Boundaries Divergent Ocean ridges Rift valleys; may fill in with water
33. Divergent Plate Boundaries 4-
34. Convergent Plate Boundaries 4-
35. Transform Plate Boundary 4-
36. East African Rift Valley 4-
37. East African Rift Valley 4-
38. Future of African Continent? 4- http://www.pmfias.com/wp-content/uploads/2015/12/East-African-Rift-Valley-break-up.jpg
40. Скачать презентацию

Слайд 2

4-
Deformation of Rocks
A force causes stress on rocks
Rocks near surface are

elastic and will return to original form when stress is removed
Elastic limit – point at which rocks are no longer elastic and deformation becomes permanent
Rocks can be brittle or ductile
Rocks deform, slide by each other along point of fracture or fault

Слайд 3

Three Types of Stress
4-
Compression – pushes on rocks from opposite directions;

shortens rocks
Tension – pulls from opposite directions; stretches / lengthens
Shear – pressure in uneven manner; rocks become skewed
Temperature, time and pressure are factors in stress.

Слайд 4

4-
Earth’s Interior
Internal heat source is energy causing metamorphism, uplift of crust

(rock cycle)
Seismic waves (earthquake waves)
Travel at different speeds through different materials
Reflect and refract when density changes
Has allowed scientists to determine boundaries b/w materials within Earth

Слайд 5

4-
Earth’s Structure

Слайд 6

4-
Earth’s Structure
Crust –
Less dense layer
Lithosphere < 15 km, brittle rigid, broken

into tectonic plates
Mantle
~2,900 km (1,800 mi) thick
Rocky, iron rich silicates, upper layer is asthenosphere
Silicates nearer to melting point; usual source of magma

Слайд 7

Earth’s Interior
Scientists hypothesize inner and outer core are iron-nickel alloy
Outer

core
Metallic liquid
Inner core
Metallic solid

Слайд 8

4-
Earth’s Magnetic Field
Inner core is solid, rotates faster than planet
Electrically charged

metallic ions in outer core circulate
Generates magnetic field
Used for magnetic north in compasses
Blocks some solar radiation

Слайд 9

4-
Earth’s Magnetic Field

Слайд 10

4-
Earth’s Internal Heat
Geothermal gradient 25°C/km – temperature increases with depth
Heat from

radioactive decay of U, Th, & K
Friction (internal compression) and pressure
Conduction – heat transferred through atmosphere to space
Convection transfers heat; driven by temperature induced changes in density

Слайд 11

Earth’s Internal Heat
4-

Слайд 12

4-
Continental Drift
Idea that continents were once joined first proposed in 1596

by Dutch mapmaker
1850s – American writer noted how S. America and Africa shorelines fit together
Frank Taylor, American geologist, 1910 suggested the continents were once joined

Слайд 13

Continental Drift
Alfred Wegener 1922 book on theory of continental drift
More evidence

than Taylor –
similar sequences of rocks
fossil evidence
coal in Antarctica
evidence of past glaciation in tropical and desert areas
Proposed supercontinent, Pangaea
Could not fully explain how

Слайд 14

4-
Developing Theory of Plate Tectonics

Слайд 15

4-
Developing Theory of Plate Tectonics
Mapping ocean floor began in 1855 by

U.S. Navy
WW1 and sonar
1950s many sonar surveys by scientists
Mid oceanic ridges – mountain chain in Atlantic Ocean
Ocean trenches as deep as 35,000 ft
Map location and depths of earthquakes
Fall on plate boundaries
Polar wandering
Moving poles and continents supported data

Слайд 16

Mapping the Ocean Floor
4-

Слайд 17

Magnetic Studies
Igneous basalts contain iron mineral magnetite (Fe3O4)
Magnetite is naturally magnetic
Atoms

orient parallel to Earth’s magnetic field when rock cools
Field of paleomagnetism studies changes in magnetic poles over geologic time

Слайд 18

Magnetic Reversal
Figure 4.11 Page 101

Слайд 19

Sea Floor Spreading
Figure 4.12, Page 101
Mid oceanic ridges – magma erupts

forming new ocean crust
Rocks older farther away from ridge crests
1968 – drilling and dating basalts
Oldest part of sea floor 200 million yrs old
Atlantic basin growing, crust material destroyed in trenches in Pacific basin

Слайд 20

Earthquakes
Earthquake – release of energy that occurs when rocks are deformed

past their elastic limit causing a rupture
Energy travels out in seismic waves
Epicenter – point on the surface that directly overlies point where rocks rupture
1960s – global network of seismic recording stations

Слайд 21

Earthquake Locations
Figure 4.13, Page 102

Слайд 22

Earthquake Locations
Epicenters along Mid Atlantic Ridge – magma rises up, buckles

crust forming ridge
Epicenters coincide with continental mountain ranges
Subduction occurs when plate is forced downward into mantle; associated with volcanic activity at ocean trenches

Слайд 23

Last Piece of Evidence for Continental Drift
Magnetite rocks form/cool, atoms orient

to magnetic north pole
Throughout geologic time, rocks orient to different location – “polar wandering”
Different continents had different paths
Paleomagnetic and sea floor spreading studies prove continents were moving no the N. pole

Слайд 24

Polar Wandering
4-

Слайд 25

4-
Plate Tectonics and Earth’s Systems
By 1960, 50 years of data proved

sea floor spreading at mid ocean ridges
New crust formed at ridges, and crust destroyed at trenches through subduction
Tectonic Plates
Earth’s lithosphere broken up into 7 major plates

Слайд 26

Plate Tectonics and Earth’s Systems
Plate Boundaries defined by epicenters
Plates move over

asthenosphere
Slide past
Override
Tear
Push into each other creating pressure ridges
Plate movement creates volcanic eruptions and mountain ranges

Слайд 27

4-
Plates

Слайд 28

Plate Boundaries
Movement generates compression, tension or shear
3 Types of Boundaries
Divergent
Convergent
Transform
See

Figure 4.19 Page 107

Слайд 29

4-
Plate Boundaries

Слайд 30

4-
Movement of Plates Figure 4.17, Page 106

Слайд 31

Surface Features & Plate Boundaries
Convergent
Oceanic-oceanic island arc; one plates undergoes subduction;

may produce an island arc
Oceanic-continental - continental arc formed; oceanic plate undergoes subduction; volcanic activity
Andes Mountains along S. America’s west coast
Cascades in Pacific Northwest of U.S.
Continental-continental - mountain belt, both plates are low density continental crust
Appalachian Mountains
Himalayas in Asia
Alps in Europe

Слайд 32

4-
Surface Features & Plate Boundaries
Divergent
Ocean ridges
Rift valleys; may fill in

with water
Transform – plates “side swipe” each other; shear forces; most in ocean plates; no subduction
San Andreas fault
See figures on pages 110 - 111

Слайд 33

Divergent Plate Boundaries
4-

Слайд 34

Convergent Plate Boundaries
4-

Слайд 35

Transform Plate Boundary
4-

Слайд 36

East African Rift Valley
4-

Слайд 37

East African Rift Valley
4-

Слайд 38

Structure and Plate Tectonics

Содержание

4-Deformation of RocksA force causes stress on rocksRocks near surface are

Three Types of Stress4-Compression – pushes on rocks from opposite directions;

4-Earth’s InteriorInternal heat source is energy causing metamorphism, uplift of crust

4-Earth’s Structure

4-Earth’s StructureCrust –Less dense layerLithosphere < 15 km, brittle rigid, broken

Earth’s Interior Scientists hypothesize inner and outer core are iron-nickel alloyOuter

4-Earth’s Magnetic FieldInner core is solid, rotates faster than planetElectrically charged

4-Earth’s Magnetic Field

4-Earth’s Internal HeatGeothermal gradient 25°C/km – temperature increases with depthHeat from

Earth’s Internal Heat4-

4-Continental DriftIdea that continents were once joined first proposed in 1596

Continental DriftAlfred Wegener 1922 book on theory of continental driftMore evidence

4-Developing Theory of Plate Tectonics

4-Developing Theory of Plate TectonicsMapping ocean floor began in 1855 by

Mapping the Ocean Floor4-

Magnetic StudiesIgneous basalts contain iron mineral magnetite (Fe3O4)Magnetite is naturally magneticAtoms

Magnetic ReversalFigure 4.11 Page 101

Sea Floor SpreadingFigure 4.12, Page 101Mid oceanic ridges – magma erupts

EarthquakesEarthquake – release of energy that occurs when rocks are deformed

Earthquake LocationsFigure 4.13, Page 102

Earthquake LocationsEpicenters along Mid Atlantic Ridge – magma rises up, buckles

Last Piece of Evidence for Continental DriftMagnetite rocks form/cool, atoms orient

Polar Wandering4-

4-Plate Tectonics and Earth’s SystemsBy 1960, 50 years of data proved

Plate Tectonics and Earth’s SystemsPlate Boundaries defined by epicentersPlates move over

4-Plates

Plate BoundariesMovement generates compression, tension or shear3 Types of BoundariesDivergentConvergentTransform See

4-Plate Boundaries

4-Movement of Plates Figure 4.17, Page 106

Surface Features & Plate BoundariesConvergentOceanic-oceanic island arc; one plates undergoes subduction;

4-Surface Features & Plate BoundariesDivergent Ocean ridgesRift valleys; may fill in

Divergent Plate Boundaries4-

Convergent Plate Boundaries4-

Transform Plate Boundary4-

East African Rift Valley4-

East African Rift Valley4-

Future of African Continent?4-http://www.pmfias.com/wp-content/uploads/2015/12/East-African-Rift-Valley-break-up.jpg

Похожие презентации

4-
Deformation of Rocks
A force causes stress on rocks
Rocks near surface are

Three Types of Stress
4-
Compression – pushes on rocks from opposite directions;

4-
Earth’s Interior
Internal heat source is energy causing metamorphism, uplift of crust

4-
Earth’s Structure

4-
Earth’s Structure
Crust –
Less dense layer
Lithosphere < 15 km, brittle rigid, broken

Earth’s Interior
Scientists hypothesize inner and outer core are iron-nickel alloy
Outer

4-
Earth’s Magnetic Field
Inner core is solid, rotates faster than planet
Electrically charged

4-
Earth’s Magnetic Field

4-
Earth’s Internal Heat
Geothermal gradient 25°C/km – temperature increases with depth
Heat from

Earth’s Internal Heat
4-

4-
Continental Drift
Idea that continents were once joined first proposed in 1596

Continental Drift
Alfred Wegener 1922 book on theory of continental drift
More evidence

4-
Developing Theory of Plate Tectonics

4-
Developing Theory of Plate Tectonics
Mapping ocean floor began in 1855 by

Mapping the Ocean Floor
4-

Magnetic Studies
Igneous basalts contain iron mineral magnetite (Fe3O4)
Magnetite is naturally magnetic
Atoms

Magnetic Reversal
Figure 4.11 Page 101

Sea Floor Spreading
Figure 4.12, Page 101
Mid oceanic ridges – magma erupts

Earthquakes
Earthquake – release of energy that occurs when rocks are deformed

Earthquake Locations
Figure 4.13, Page 102

Earthquake Locations
Epicenters along Mid Atlantic Ridge – magma rises up, buckles

Last Piece of Evidence for Continental Drift
Magnetite rocks form/cool, atoms orient

Polar Wandering
4-

4-
Plate Tectonics and Earth’s Systems
By 1960, 50 years of data proved

Plate Tectonics and Earth’s Systems
Plate Boundaries defined by epicenters
Plates move over

4-
Plates

Plate Boundaries
Movement generates compression, tension or shear
3 Types of Boundaries
Divergent
Convergent
Transform
See

4-
Plate Boundaries

4-
Movement of Plates Figure 4.17, Page 106

Surface Features & Plate Boundaries
Convergent
Oceanic-oceanic island arc; one plates undergoes subduction;

4-
Surface Features & Plate Boundaries
Divergent
Ocean ridges
Rift valleys; may fill in

Divergent Plate Boundaries
4-

Convergent Plate Boundaries
4-

Transform Plate Boundary
4-

East African Rift Valley
4-

East African Rift Valley
4-

Future of African Continent?
4-
http://www.pmfias.com/wp-content/uploads/2015/12/East-African-Rift-Valley-break-up.jpg