2. The Dynamic CrustThe Dynamic Crust
I.I. Evidence of Crustal Changes –Evidence of Crustal Changes – or HOW do we knowor HOW do we know
that movement of rocks takes place on Earth?that movement of rocks takes place on Earth?
A. Deformed Rock Structure - Sedimentary strataA. Deformed Rock Structure - Sedimentary strata
normally form in anormally form in a horizontalhorizontal position. Any change. Any change
from the horizontal position is evidence offrom the horizontal position is evidence of minorminor
crustal changecrustal change
9. II. Plate TectonicsII. Plate Tectonics
1. Crust
5 – 35 km thick
Density 2.7 – 3.0 g/cc
2. Mantle
2,900 km thick
Density 3.3 – 5.5 g/cc
3. Outer Core
2,250 km thick
Density 9.9 – 12.1 g/cc
4. Inner Core
1,220 km thick
Density 12.7 – 13.0 g/cc
10. The crust contains bothThe crust contains both
oceanic crustoceanic crust which iswhich is
covered by our oceanscovered by our oceans
andand continental crustcontinental crust,,
that is the land on whichthat is the land on which
we live.we live.
13. C.C. Lithosphere =Lithosphere = CrustCrust + Upper MantleUpper Mantle
D.D. AsthenosphereAsthenosphere – the plastic-like layer– the plastic-like layer
below the lithosphere in Earth’s Mantlebelow the lithosphere in Earth’s Mantle
14. 3. Theory of Continental Drift3. Theory of Continental Drift
a.a. Alfred WegnerAlfred Wegner ––
proposed the theory ofproposed the theory of
Continental Drift in theContinental Drift in the
early 1900’s.early 1900’s.
b.b. He proposed thatHe proposed that
approximately 200 mya,approximately 200 mya,
all the continents existedall the continents existed
as one large land massas one large land mass
which he calledwhich he called
Pangaea.Pangaea.
15.
16. Dynamic CrustDynamic Crust
SCRAT’s take on Plate TectonicsSCRAT’s take on Plate Tectonics
For your viewing pleasure onlyFor your viewing pleasure only
Don’t believe everything you see in theDon’t believe everything you see in the
movies....hahamovies....haha
17.
18. C. Evidence for Continental DriftC. Evidence for Continental Drift
1.1. Coastline of theCoastline of the
continents – forcontinents – for
example, the eastexample, the east
coast ofcoast of SouthSouth
AmericaAmerica fits wellfits well
with the west coastwith the west coast
ofof AfricaAfrica – like the– like the
pieces of a giantpieces of a giant jig-jig-
saw puzzle.saw puzzle.
19. 2. Fossil Clues – certain fossils of2. Fossil Clues – certain fossils of
ancient life formsancient life forms are found onare found on
widely separated continents.widely separated continents.
MesosaurusMesosaurus
was a smallwas a small
freshwaterfreshwater
reptile. It’sreptile. It’s
fossils arefossils are
found infound in
AfricaAfrica andand
SouthSouth
AmericaAmerica
20. GlossopterisGlossopteris – it was an ancient seed-fern– it was an ancient seed-fern
(with very large heavy seeds). It’s fossils are(with very large heavy seeds). It’s fossils are
found infound in Africa,Africa, India , Australia, Antarctica and
South AmericaSouth America
21. 3. Rock Clues3. Rock Clues
a.a. TheThe AppalachianAppalachian
Mountains of the easternMountains of the eastern
US are geologicallyUS are geologically
similar to the mountainssimilar to the mountains
in Greenland andin Greenland and
western Europe, whichwestern Europe, which
include the Caledonianinclude the Caledonian
Mountains of Scotland.Mountains of Scotland.
b.b. Structure, age, andStructure, age, and
mineral content of rocksmineral content of rocks
are similar on the coastsare similar on the coasts
of easternof eastern SouthSouth
America and westernAmerica and western
Africa.Africa.
22. 4.4. Climate CluesClimate Clues
a.a. Coal, which formsCoal, which forms
from plants thatfrom plants that
grow in warmgrow in warm
swampyswampy
environments, isenvironments, is
found today in thefound today in the
colder climates ofcolder climates of
North America andNorth America and
Antarctica.Antarctica.
23. b. Coral limestone, containing the remains of coral,, containing the remains of coral,
which once lived inwhich once lived in warm seaswarm seas, is found today in, is found today in
northern latitudes such asnorthern latitudes such as North CarolinaNorth Carolina..
24. c.c. Ancient rocks of theAncient rocks of the
same agesame age near thenear the
equator in Southequator in South
America, SouthAmerica, South
Africa and otherAfrica and other
southernsouthern
landmasses showlandmasses show
evidence ofevidence of
glaciationglaciation..
25. Continental Drift LabContinental Drift Lab
Questions?Questions?
4. Where in the4. Where in the
United States isUnited States is
therethere
measurablemeasurable
evidence thatevidence that
the continentsthe continents
are movingare moving
relative to onerelative to one
another?another?
26. C. Theory of Sea Floor SpreadingC. Theory of Sea Floor Spreading
A.A. Topography of the ocean floorTopography of the ocean floor
Label on your diagramLabel on your diagram
SeamountSeamount
Abyssal plainAbyssal plain
Rift-valleyRift-valley
Mid-Ocean RidgeMid-Ocean Ridge
TrenchTrench
Continental SlopeContinental Slope
Continental ShelfContinental Shelf
Mid-OceanRidge
RiftValley
27. B. Evidence for Sea Floor SpreadingB. Evidence for Sea Floor Spreading
1.1. Age Evidence – AsAge Evidence – As
the distance fromthe distance from
the ocean ridgethe ocean ridge
increasesincreases, the age, the age
of the rockof the rock
increasesincreases..
youngest
28. 2.2. Magnetic Evidence (PaleomagnetismMagnetic Evidence (Paleomagnetism) –) –
magnetic clues from the iron-bearing basalt rockmagnetic clues from the iron-bearing basalt rock
of the ocean floor supports the theory of seafloorof the ocean floor supports the theory of seafloor
spreading.spreading.
30. C. The Theory of Plate TectonicsC. The Theory of Plate Tectonics
1.1. The Theory of Plate Tectonics states that Earth’sThe Theory of Plate Tectonics states that Earth’s
lithospherelithosphere (crust + upper mantle) is divided into(crust + upper mantle) is divided into
sections calledsections called lithospheric plateslithospheric plates..
31. 2.2. Plate MotionPlate Motion – The theory of Plate Tectonics states– The theory of Plate Tectonics states
that these lithospheric plates are in motion and “float”that these lithospheric plates are in motion and “float”
or ride on theor ride on the asthenosphereasthenosphere..
32. 3.3. Direction of Plate Movement – the movement and interaction of tectonicDirection of Plate Movement – the movement and interaction of tectonic
plates creates 3 types of plate boundaries: the arrows on the tectonicplates creates 3 types of plate boundaries: the arrows on the tectonic
map in your notes show the relative motion.map in your notes show the relative motion.
33. 4. Types of Plate Boundaries4. Types of Plate Boundaries
36. B. Convergent Plate Boundaries –B. Convergent Plate Boundaries – Where 2 platesWhere 2 plates
come together or collidecome together or collide..
1. Oceanic-Continental –
Subduction Zone
Example: Nazca (oceanic)
subducts under South
American (continental)
37.
38. 2. Oceanic – Oceanic – Trenches and island
arcs of Japan and Alleutian Islands (Alaska)
39. 3. Continental –
Continental –
Indian/Australian
Plate Colliding with
Eurasian Plate
forming the
Himalaya
Mountains
40. C.C. Transform Plate BoundariesTransform Plate Boundaries –– 22 plates thatplates that
“slip” past one another. Ex: San Andreas Fault“slip” past one another. Ex: San Andreas Fault
41. D.D. Convection CurrentsConvection Currents == the driving force beneaththe driving force beneath
plate tectonicsplate tectonics
Hot,Hot, LESSLESS densedense
material from deepmaterial from deep
within Earth’s mantlewithin Earth’s mantle
rises. When this materialrises. When this material
cools near the surface, itcools near the surface, it
becomesbecomes MOREMORE densedense
and sinks. The resultingand sinks. The resulting
convective flow of thisconvective flow of this
material in the mantlematerial in the mantle
CARRIES/MOVESCARRIES/MOVES
lithospheric plates acrosslithospheric plates across
the surface of Earth.the surface of Earth.
Label the diagram in your
notes according to this
diagram!
43. III. EarthquakesIII. Earthquakes
A.A. SeismologySeismology – the branch of science that– the branch of science that
studies earthquakes.studies earthquakes.
44. B. Causes of Earthquakes –B. Causes of Earthquakes – Sudden movement ofSudden movement of
Earth’s crust at plate boundaries and faults.Earth’s crust at plate boundaries and faults.
1.1. Plate BoundariesPlate Boundaries
Divergent Boundaries –
usually minor,
shallow quakes
52. C. Earthquakes tell us about Earth’s surfaceC. Earthquakes tell us about Earth’s surface
movementmovement
KeyKey
Shallow = within 75
km of Earth’s
Surface
Intermediate = 75 – 300 km
Deep = 300 – 700 km
53. D. Earthquakes cause other disastersD. Earthquakes cause other disasters
TsunamiTsunami = gigantic sea waves= gigantic sea waves
Characteristics:Characteristics: Speed =Speed = 400 – 500 mph400 – 500 mph
Height =Height = 50 – 100 Feet50 – 100 Feet
59. 2. Earthquake Waves2. Earthquake Waves
a. Origin and map locationa. Origin and map location
Epicenter
Focus
Fault
Depth
FocusFocus = Point
beneath Earth’s
surface where
fault movement
releases seismic
waves (energy)
EpicenterEpicenter = the
point on Earth’s
surface directly
above the focus.
60. 1. Analysis of seismic
waves has led
scientists to infer the
layerslayers of earth.
b. Earthquake Waves and Earth’s Interiorb. Earthquake Waves and Earth’s Interior
61. b. Types of seismic wavesb. Types of seismic waves
P WavesP Waves = P or Primary Waves- Also known as= P or Primary Waves- Also known as
CompressionCompression waves - travel 6 mpswaves - travel 6 mps
Motion of matter due to P waves-alternate contractionMotion of matter due to P waves-alternate contraction
and expansion of rocks in a direction parallel to theand expansion of rocks in a direction parallel to the
direction of wave propagation.direction of wave propagation.
62. b. Types of seismic wavesb. Types of seismic waves
S or Secondary Waves- Also known asS or Secondary Waves- Also known as Shear Waves andShear Waves and traveltravel atat
4 mps4 mps
Motion of matter due to S waves-displacement of adjacent rocks inMotion of matter due to S waves-displacement of adjacent rocks in
a directiona direction perpendicularperpendicular to the direction of wave propagation.to the direction of wave propagation.
The velocity of P and S waves is controlled by how the materialThe velocity of P and S waves is controlled by how the material
through which wave is traveling responds to shear forces. It alsothrough which wave is traveling responds to shear forces. It also
depends on thedepends on the densitydensity of the material.of the material.
63. b. Types of seismic wavesb. Types of seismic waves
Love wavesLove waves surfacesurface
seismic wavesseismic waves are thatare that
cause horizontal shifting ofcause horizontal shifting of
the Earth during anthe Earth during an
earthquakeearthquake
64. C. Seismograph –C. Seismograph – measures andmeasures and
records earthquake wavesrecords earthquake waves
66. D. Locating the Epicenter
1. Need at least three (3) stations
2. Determine when P wave arrives
3. Determine when S wave arrives
4. Difference between S and P wave arrival ( t) EX: 4 min 20 seconds
5. Locate on travel-time curve what the ( t) corresponds to in distance
6. Draw circles around each station with radii=distance just determined
7. Intersection of three circles is the epicenter
Using Seismic Waves to Study Earthquakes
67. •Seismic Waves travel
through the entire Earth
•Travel at different rates
through different densitiesdensities!
•That’s why the lines
“bendbend”…….when they go
through the layers
Earth’s structure/interior is
divided into the crust, mantle,
outer core and inner core.
E. Earthquake Waves
71. Using the Drawing CompassUsing the Drawing Compass
SUMMARYSUMMARY
Read the seismograph times of P/S waveRead the seismograph times of P/S wave
Or calculate the difference between the P-S waveOr calculate the difference between the P-S wave
arrival stationsarrival stations
Use the graph on to determine the distance to theUse the graph on to determine the distance to the
epicenter.epicenter.
Use the map scale to measure the distance from eachUse the map scale to measure the distance from each
of the 3 locations and draw a circle around each city.of the 3 locations and draw a circle around each city.
The point of intersection of the 3 circles is theThe point of intersection of the 3 circles is the
EPICENTER!EPICENTER!
72. D. LocatingD. Locating
the epicenter ofthe epicenter of
an earthquakean earthquake
Method of Triangulation
VIRTUAL EARTHQUAKE
Visit the WIKI and try
it yourself!
73. IV. VolcanoesIV. Volcanoes
A. Volcanic Regions on Earth
Ring of Fire = region of volcanoes that encircle the Pacific
Ocean
