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Dynamic Crust. THEORY OF CONTINENTAL DRIFT. (ALFRED WEGENER 1915 ). I 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. Evidence.

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THEORY OF CONTINENTAL DRIFT

(ALFRED WEGENER 1915)

I 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


Evidence

CONTINENTS SEEM TO FIT TOGETHER

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)

DEPOSITS OF CERTAIN ROCK AND MINERAL TYPES CORRELATE AMONG CONTINENTS

APPALACHIAN MTS. FOUND IN NORTHEAST OF U.S. ARE SIMILAR IN AGE AND STRUCTURE AS MTS. IN GREENLAND AND SCANDINAVIA


Structure of the Earth

PRESSURE AND TEMPERATURE INCREASE AS YOU MOVE TOWARD THE CENTER OF THE EARTH

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


LITHOSPHERE- CRUST AND UPPERMOST SOLID PART OF THE MANTLE

 ASTHENOSPHERE- UNDERLIES THE LITHOSPHERE, COMPOSED OF PARTIALLY MOLTEN ROCK

MOHO- THE BOUNDARY BETWEEN THE CRUST AND THE MANTLE

MANTLE- THE LAYER OF MOLTEN ROCK EXTENDING FROM THE CRUST DOWNWARD 2850 KM

OUTER CORE- BETWEEN MANTLE AND INNER CORE, COMPOSED OF IRON AND NICKEL

INNER CORE- SOLID IRON AND NICKEL LOCATED AT THE CENTER OF THE EARTH



Plate Tectonics chart on page 10 in the ESRT

PLATE TECTONICS IS THE STUDY OF THE FORMATION AND MOVEMENT OF PLATES

PLATES ARE COMPOSED OF LITHOSPHERE (CONTINENTAL=THICK, OCEANIC=THIN) 12 MAJOR AND SEVERAL MINOR PLATES


Convection Cells chart on page 10 in the ESRT


** PLATES MOVE BECAUSE OF CONVECTION CELLS IN THE ASTHENOSPHERE**

CONVECTIONCELL- A CIRCULATORY MOTION IN A LIQUID OR GAS TRANSFERRING HEAT ENERGY THAT RESULTS FROM DIFFERENCES IN DENSITY WITHIN THE FLUID


Types of Plate Boundaries ASTHENOSPHERE**

Divergent

Convergent

Transform


Divergent Plate Boundary ASTHENOSPHERE**

*PLACE WHERE TWO PLATES ARE MOVING APART FROM EACH OTHER.

Sea Floor Spreading

a) MID-ATLANTIC RIDGE- SEA FLOOR SPREADING AT THE MID OCEAN RIDGES RECORDED BY THE REVERSAL OF THE MAGNETIC POLES IN MINERAL GRAINS


PALEOMAGNETISM- THE STUDY OF MAGNETISM IN ANCIENT ROCKS ASTHENOSPHERE**

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

Reversal of Magnetic Poles


Convergent Plate Boundary ASTHENOSPHERE**

COLLISION- WHEN TWO PLATES CARRYING CONTINENTS COLLIDE THEY PUSH UP USUALLY CAUSING MOUNTAINS. (EX. HIMALAYAS)

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 ASTHENOSPHERE**

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

OCEAN-OCEAN ONE PLATE WILL SUBDUE TO THE OTHER ONE USUALLY CAUSING A DEEP TRENCH (EX. MARIANA’S TRENCH)


Transform Plate Boundary ASTHENOSPHERE**

WHEN PLATES SLIDE PAST ONE ANOTHER USUALLY CAUSING A BUILD UP OF PRESSURE WHICH IS RELEASED IN THE FORM OF AN EARTHQUAKE

SAN ANDREAS FAULT- MANY EARTHQUAKES ARE COMMON ALONG THE FAULT WHERE THE NORTH AMERICAN PLATE IS SLIDING PAST THE PACIFIC PLATE



Evidence ASTHENOSPHERE**

Earthquakes and Volcanic activity


More Evidence.. ASTHENOSPHERE**


The Ring of Fire ASTHENOSPHERE**


Volcanism ASTHENOSPHERE**

MAGMA – MOLTEN ROCK UNDERGROUND

FELSIC – MAGMAS WITH RELATIVELY HIGH SILICA ARE THICK, LIGHT COLORED, AND SLOW MOVING

MAFIC – RELATIVELY LOW SILICA CONTENT, THINNER, DARKER, AND FLOW MORE EASILY


MAGMA CONTAINS DISSOLVED GASES THAT ARE GIVEN OFF AS THE MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

MAGMAS CONTAINING LARGE AMOUNTS OF DISSOLVED GASES TEND TO PRODUCE MORE EXPLOSIVE ERUPTIONS.

LAVA – MOLTEN ROCK THAT HAS REACHED THE SURFACE

FELSIC LAVA – THICK AND STIFF CALLED AA LAVA. PRODUCE EXPLOSIVE ERUPTIONS.

MAFIC LAVA – THIN AND FLUID CALLED PAHOEHOE LAVA. LAVA POURS OUT SMOOTHLY (LESS EXPLOSIVE)


LAVA FRAGMENTS MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

TEPHRA – SOLID FRAGMENTS OF LAVA PRODUCED FROM EXPLOSIVE ERUPTIONS.

SMALL

ASH

LAPILLI

BOMBS

LARGE


KINDS OF ERUPTIONS MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

RIFT ERUPTIONS – OCCUR AT LONG, NARROW FRACTURES IN THE CRUST SUCH AS MID-OCEAN SPREADING CENTERS

WHEN LAVA FLOWS OUT SMOOTHLY AND FLUIDLY IT FORMS A VOLCANIC MOUNTAIN WITH A BROAD BASE AND GENTLY SLOPING SIDES CALLED A SHIELD CONE


SUBDUCTION BOUNDARY ERUPTIONS MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR. – ARE THE RESULT OF THICK MAGMA THAT FORMS AT SUBDUCTION BOUNDARIES.

THESE ERUPTIONS AR MORE EXPLOSIVE DUE TO THE LARGE AMOUNT OF GASES IN THE MAGMA.

FORMS A CINDER CONE WITH VERY STEEP SIDES


HOT SPOTS MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

HOT SPOTS ARE AREAS OF VOLCANIC ACTIVITY IN THE MIDDLE OF LITHOSPHERIC PLATES.

SIMILAR TO RIFT ERUPTIONS. SMOOTH FLOWING LAVA AND SHIELD CONES.

** THE HOT SPOT STAYS IN THE SAME LOCATION AS THE LITHOSPHERIC PLATE ABOVE IT MOVES **


EARTHQUAKES MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

AN EARTHQUAKE IS A SHAKING OF EARTH’S CRUST CAUSED BY THE RELEASE OF ENERGY.

REASONS WHY THEY OCCUR:

ERUPTION OF A VOLCANO

THE COLLAPSE OF A CAVERN

THE IMPACT OF A METEOR

SUDDEN MOVEMENT ALONG A PLATE BOUNDARY CAUSED BY THE RELEASE OF STRESS


DEPTH OF MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.EARTHQUAKES

FOCUS – THE POINT ON A FAULT PLANE AT WHICH THE FIRST MOVEMENT OCCURS

EPICENTER – THE POINT ON EARTH’S SURFACE DIRECTLY ABOVE THE FOCUS


EARTHQUAKE WAVES MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

THREE BASIC KINDS OF WAVES

P-WAVES (PRIMARY) – BACK AND FORTH WAVE MOTION; CAN TRAVEL THROUGH ANY MATERIAL; FASTEST

S-WAVES (SECONDARY) – SIDE TO SIDE WAVE MOTION; CAN TRAVEL THROUGH SOLIDS BUT NOT THROUGH LIQUIDS OR GASES

L-WAVES (SURFACE) – FORM WHEN P AND S WAVES REACH THE SURFACE WHICH MOVE SLOWLY LIKE RIPPLES ON A POND; SLOWEST


LOCATING AN EARTHQUAKE MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

SEISMOGRAPH – THE INSTRUMENT THAT DETECTS AND RECORDS EARTHQUAKE WAVES

SEISMOGRAM – THE SHEET WHICH DISPLAYS THE ZIG-ZAG TRACE OF EARTHQUAKE WAVES

**P-WAVES ALWAYS ARRIVE BEFORE S-WAVES**

P AND S WAVE ARRIVAL TIME DIFFERENCE CAN THEN BE USED TO DETERMINE THE DISTANCE FROM THE RECORDING STATION TO THE EPICENTER


SHADOW ZONE MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

THE SHADOW ZONE IS A WIDE BELT AROUND EARTH ON THE SIDE OPPOSITE THE FOCUS OF THE EARTHQUAKE. SEISMIC STATIONS RECEIVE NEITHER P NOR S WAVES.

THE CAUSE OF THE SHADOW ZONE IS THE EARTH’S OUTER CORE. S-WAVES CAN NOT TRAVEL THROUGH THE LIQUID OUTER CORE. WHILE P WAVES ARE REFRACTED (BENT) IN A SMOOTH ARC BACK TO THE SURFACE.


OTHER CRUSTAL CHANGES MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

ORIGINAL HORIZONTALITY- CONCEPT THAT SEDIMENTARY ROCKS FORM IN HORIZONTAL LAYERS PARALLEL TO THE EARTH’S SURFACE.

DEFORMED ROCKS- ANY ROCK LAYERS WHICH NO LONGER SHOW HORIZONTALITY

UPLIFT- LAND WHICH HAS BEEN RAISED UP TO ITS PRESENT POSITION (EVIDENCE- MARINE FOSSILS IN MOUNTAINS)

FOLDS- ROCK LAYERS WHICH ARE BENT OR CURVED CAUSED FROM GREAT PRESSURE ON THE ROCK


OTHER CRUSTAL CHANGES MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

FOLDS- ROCK LAYERS WHICH ARE BENT OR CURVED CAUSED FROM GREAT PRESSURE ON THE ROCK

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


PLEASE TURN TO PAGE 11 IN YOUR ESRT MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.


Review of Plate Boundaries MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

Who created the theory of “continental drift” ?

Give two forms of evidence to support this theory.

What is the difference between the lithosphere and the asthenosphere?

Describe how a convection cell works.


Review of Plate Boundaries MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

What type of boundary is this?


Review of Plate Boundaries MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

What type of boundary is this?


Review of Plate Boundaries MAGMA ERUPTS. THE MOST IMPORTANT OF THESE GASES ARE WATER VAPOR, CARBON DIOXIDE, AND SULFUR.

What type of boundary is this?


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