DYNAMIC CRUST
I THEORY OF CONTINENTAL DRIFT (ALFRED
WEGENER 1915)
1) PANGEA- A LARGE LANDMASS CONTAINING ALL
OF THE CONTINENTS. WHICH EVENTUALLY
BROKE INTO TWO LANDMASSES
A) LAURASIA- N. AMERICA, EUROPE, ASIA
B) GONDWANALAND- AFRICA, S. AMERICA,
ANTARCTICA, AUSTRALIA, INDIA
2) EVIDENCE TO SUPPORT THE THEORY
A) CONTINENTS SEEM TO FIT TOGETHER
B) FOSSILS OF INDIVIDUAL SPECIES CAN BE
FOUND ON MANY DIFFERENT CONTINENTS
WHICH ARE NOT CLOSE TOGETHER. (EX.
LYSTROSAURUS WAS LOCATED IN
ANTARCTICA, S. AMERICA, AFRICA, INDIA)
C) DEPOSITS OF CERTAIN ROCK AND MINERAL
TYPES CORRELATE AMONG CONTINENTS
D) APPALACHIAN MTS. FOUND IN NORTHEAST OF
U.S. ARE SIMILAR IN AGE AND STRUCTURE AS
MTS. IN GREENLAND AND SCANDINAVIA
E) PLATE TECTONICS
II STRUCTURE OF THE EARTH
1) CRUST- THE OUTER MOST LAYER OF THE
EARTH
A) CONTINENTAL CRUST- COMPOSED MAINLY
OF GRANITE, LOW IN DENSITY
B) OCEANIC CRUST- COMPOSED MAINLY OF
BASALT, HIGH IN DENSITY
2) MOHO- THE BOUNDARY BETWEEN THE CRUST
AND THE MANTLE
3) MANTLE- THE LAYER OF ROCK EXTENDING
FROM THE CRUST ODWNWARD 2850 KM
4) LITHOSPHERE- CRUST AND UPPERMOST SOLID
PART OF THE MANTLE
5) ASTHENOSPHERE- UNDERLIES THE
LITHOSPHERE, COMPOSED OF PARTIALLY
MOLTEN ROCK
6) OUTER CORE- BETWEEN MANTLE AND INNER
CORE, COMPOSED OF IRON AND NICKEL
7) INNER CORE- SOLID IRON AND NICKEL
LOCATED AT THE CENTER OF THE EARTH
III
PLATE TECTONICS
1) PLATE TECTONICS IS THE STUDY OF THE
FORMATION AND MOVEMENT OF PLATES
2) PLATES- COMPOSED OF LITHOSPHERE
(CONTINENTAL=THICK, OCEANIC=THIN) 12
MAJOR AND SEVERAL MINOR PLATES
3) ** PLATES MOVE BECAUSE OF CONVECTION
CELLS IN THE ASTHENOSPHERE
A) CONVECTIONCELL- A CIRCULATORY MOTION
IN A FLUID TRANSFERRING HEAT ENERGY
THAT RESULTS FROM DIFFERENCES IN
DENSITY WITHIN THE FLUID
4) EVIDENCE
A) EARTHQUAKES AND VOLCANIC ACTIVITY
MAINLY FOUND OCCURRING ALONG PLATE
BOUNDARIES (“RING OF FIRE”)
B) SEA FLOOR SPREADING (REVERSAL OF THE
MAGNETIC POLES)
C) EVIDENCE FROM THE THEORY OF
CONTINENTAL DRIFT
IV TYPES OF PLATE BOUNDARIES
1) DIVERGENT- PLACE WHERE TWO PLATES ARE
MOVING APART FROM EACH OTHER.
A) PALEOMAGNETISM- THE STUDY OF
MAGNETISM IN ANCIENT ROCKS
B) POLAR WANDERING- AS METALLIC MINERAL
GRAINS ALIGN THEMSELVES WITH THEIR
MAGNETIC POLES ROCK RECORDS SHOW
THAT THE GRAINS REVERSE THE DIRECTION
IN WHICH THEY POINT 0
C) MID-ATLANTIC RIDGE- SEA FLOOR
SPREADING AT THE MID OCEAN RIDGES
RECORDED BY THE REVERSAL OF THE
MAGNETIC POLES IN MINERAL GRAINS
2) CONVERGENT- WHEN TWO PLATES MOVE
TOWARDS EACH OTHER
A) COLLISION- WHEN TWO PLATES CARRYING
CONTINENTS COLLIDE THEY PUSH UP
USUALLY CAUSING MOUNTAINS. (EX.
HIMALAYAS)
B) SUBDUCTION- WHEN BOTH PLATES DO NOT
CONTAIN CONTINENTS, ONE OF THE PLATES IS
FORCED TO SINK UNDER THE OTHER ONE.
THE PLATE WHICH SUBDUES IS COMPOSED OF
A MORE DENSE MATERIAL.
1) OCEAN-CONTINENT THE OCEAN FLOOR IS
MORE DENSE SO IT SUBDUES TO THE
CONTINENTAL CAUSING OFFSHORE
TRENCHES, MOUNTAINS OR VOLCANOES
(EX. WESTERN COAST OF S. AMERICA)
2) OCEAN-OCEAN ONE PLATE WILL SUBDUE
TO THE OTHER ONE USUALLY CAUSING A
DEEP TRENCH (EX. MARIANA’S TRENCH)
3) TRANSFORM- WHEN PLATES SLIDE PAST ONE
ANOTHER USUALLY CAUSING A BUILD UP OF
PRESSURE WHICH IS RELEASED IN THE FORM OF
AN EARTHQUAKE
A) SAN ANDREAS FAULT- MANY EARTHQUAKES
ARE COMMON ALONG THE FAULT WHERE THE
NORTH AMERICAN PLATE IS SLIDING PAST
THE PACIFIC PLATE
V CRUSTAL CHANGES
1) ORIGINAL HORIZONTALITY- CONCEPT
ASSUMES THAT SEDIMENTARY ROCKS FORM IN
HORIZONTAL LAYERS PARALLEL TO THE
EARTH’S SURFACE.
2) DEFORMED ROCKS- ANY ROCK LAYERS WHICH
NO LONGER SHOW HORIZONTALITY
3) UPLIFT- LAND WHICH HAS BEEN RAISED UP TO
ITS PRESENT POSITION (EVIDENCE- MARINE
FOSSILS IN MOUNTAINS)
4) FOLDS- ROCK LAYERS WHICH ARE BENT OR
CURVED CAUSED FROM GREAT PRESSURE ON
THE ROCK
5) FAULTS- ROCK LAYERS OFFSET OR DISPLACED
ALONG A CRACK
HANGING WALL- IS ON THE TOP OF THE CRACK
FOOT WALL- IS ON THE BOTTOM OF THE CRACK
A) NORMAL-HANGING WALL MOVES DOWN
B) REVERSE (THRUST)- HANGING WALL MOVES
UP
C) TRANSFORM- VERTICAL CRACK IN THE
LAYERS, SIDE BY SIDE MOTION
VI EARTHQUAKES
1) EARTHQUAKE IS A NATURAL RAPID SHAKING
OF THE LITHOSPHERE CAUSED BY THE RELEASE
OF ENERGY STORED IN ROCKS, USUALLY BY
MOVEMENT ALONG FAULTS
2) FOCUS- LOCATION ON THE PLANE OF THE
FAULT AT WHICH MOVEMENT BEGINS
3) EPICENTER- LOCATION AT THE EARTH’S
SURFACE DIRECTLY ABOVE THE FOCUS
4) SEISMIC WAVES- EARTHQUAKE WAVES
A) SEISMOGRAPH- INSTRUMENT WHICH
RECORDS EARTH’S WAVE MOVEMENT
B) P-WAVES- (PRIMARY) TRAVEL FASTEST AND
PASS THROUGH ALL MATERIALS
C) S-WAVES- (SECONDARY) SECOND FASTEST
WAVES WHICH ONLY PASS THROUGH SOLIDS
D) SURFACE WAVES- FORM AT OR NEAR THE
SURFACE OF THE EARTH WHEN P AND S
WAVES COMBINE TO CAUSE MUCH OF THE
SHAKING AND DAMAGE
5) MAGNITUDE OF EARTHQUAKES- MEASURED BY
MAGNITUDE SCALES WHICH MEASURE THE
RELEASE OF PRESSURE WHEN AN EARTHQUAKE
OCCURRS AND THE DAMAGE IT MAY CAUSE.
(EX. RICHTER)