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A Planet on the Move
Geological Processes of Earth
By Jeff Pathfinder
Heritage Intermediate School
6th Grade
Objectives
• Describe how the continents have moved
over the past 250 billion years.
• Provide support for these theories.
• Explain the effects of this movement on
the Earth’s surface.
Introduction
• Study the shapes of the continents closely
while looking at a globe or map of the
world. Do you notice anything about the
continents on opposite sides of the Atlantic
Ocean?
Continental Drift
• Alfred Wegener did! A German
geologist, Wegener proposed
the theory of continental drift. He
calculated that 200 million years
ago the continents were
originally joined together,
forming a large super continent.
He named this super continent
Pangaea, meaning "All-earth".
http://dgl.mircrosoft.com.html
Evidence...
Same type of rocks
on each continent.
Same type
fossils on
each
continent.
Seafloor Spreading
• In the 1950’s scientists began to look at the
ocean floor for evidence of this movement.
• They noticed deep sea trenches and rifts.
• Age Evidence and Magnetic Clues provided
further evidence that Wegner had been
correct!
Plate Tectonics
• In the 1960’s scientists theorized Plate
Tectonics.
• Earth is made of 10 plates that “slide” around
on the plastic-like layer of the earth below the
crust called the asthenosphere.
Plate Movement
• Convergent
• Divergent
• Transformanother…earthquakes
Convergent
Plates collide…volcanoes, mountains
http://pubs.usgs.gov/publications/text/understanding.html
Divergent
Plates move apart…ridges, rift valleys
Copywrite 1999 John Wiley and Sons, Inc.
Transform
Plates slide past one another…earthquakes!
Copywrite 1999 John Wiley and Sons, Inc.
Do You Remember?
• 1. Define Pangaea.
• 2. Describe Wagner’s theory.
• 3. What evidence is there of Seafloor
Spreading?
• 4. Describe Plate Tectonics.
• 5. Name and describe the 3 Plate
Boundaries.
http://www.branches.co.uk/earth/tectonic.htm
Works Cited
Earth Science, Glencoe/ McGraw
Hill. Columbus, Ohio, 2001
Research and images ,
http://www.enchantedlearning.com
http://dgl.mircrosoft.com.html
http://pubs.usgs.gov/publications/text/
understanding.html
Copywrite 1999 John Wiley and Sons,
Inc.