CONTINENTAL DRIFT The process by which the continents move
slowly across Earths surface.
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PLATE TECTONICS The theory that pieces of the Earths
lithosphere, called plates, move about slowly on top of the
asthenosphere.
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ALFRED WEGENER German scientist who first introduced the theory
Kontinentalverschiebung... AKA CONTINETAL DRIFT Recognized that
South America and Africa fit together like a puzzle
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PANGEA
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Whats the evidence???? Similarities of coastlines of continents
(fit together like a puzzle) Discoveries and correlations of
worldwide distribution of plant and animal fossils Records of
Earths ancient magnetism captured in lava flows
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Whats the evidence???? Observations of the flow of heat from
Earths interior Studies of the nature and exploration of the ocean
floor Locations of volcanoes and records of earthquakes
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The evidence Wegener needed Seafloor Spreading: The movement of
the ocean floor away from either side of a mid-ocean ridge Creates
NEW CRUST!!!
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Mid-Ocean Ridges: A system of undersea mountain ranges that
wind around the earth
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Subduction: When one plate moves under another plate at a plate
boundary. Why does this happen?? Oceanic crust is more dense than
continental crust, so it is forced under the less dense material
Zone of Subduction
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Oceanic-oceanic crust Oceanic-continental crust Forms: Volcanic
Island Arcs & Deep trenches
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Understanding the Theory of Plate Tectonics The theory not only
describes continental movement, but also proposes an explanation of
WHY and HOW continents move. Tectonics is the study of the
formation of features in the Earths crust. The theory that pieces
of the Earths lithosphere, called plates, move about slowly on top
of the asthenosphere.
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Crust Lithosphere Mantle Outer Core Inner Core
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CRUST: outer surface; can be oceanic or continental
LITHOSPHERE: rigid interior of crust ASTHENOSPHERE: plastic upper
mantle MANTLE: molten rock OUTER CORE: liquid iron nickel INNER
CORE: solid iron nickel Solid rock that slowly flows (Like
putty)
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PLATE BOUNDARIES DivergentConvergentTransform Fault Pull away
from each otherCrash into each otherSlide past each other
Tension Rocks are pulled apart Occurs at divergent boundaries
Rocks become thinner
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Compression Crustal rocks are pressed together Occurs at
convergent boundaries Pushes rock higher up or deeper down in the
crust
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Shearing This stress pushes rocks in opposite direction Sheared
rock bends, breaks, and twists as they slide past each other Occurs
at transform faults
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Result of Stress ANTICLINE: up-curved folds in layers of rock
SYNCLINE: down-curved folds in layers of rock MONOCLINE: gently
dipping bends in horizontal rock layers
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Anticline
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Syncline
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Monocline
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Result of Stress If there is no movement on either side of
breakthis is a fracture. When there is movement, this is a
fault
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Normal fault Occur along divergent boundaries and the hanging
wall moves downward, relative to the footwall Reverse fault Occurs
along convergent boundaries and the hanging wall moves upward,
relative to the footwall Strike-slip fault Occurs along transform
fault boundaries and the rock on either side of fault slides
horizontally Thrust fault special reverse fault where fault plane
is nearly horizontal (common in steep mountains)
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http://youtu.be/ryrXAGY1dmE Hawaii Hotspot Hawaii Hotspot
Seafloor spreading and Megathrust