Plate Tectonics and Continental Drift
TEKS Objectives:
• (8.3) Scientific processes. The student uses critical thinking
and scientific problem solving to make informed decisions.
The student is expected to:
– (A) Analyze, review, and critique scientific explanations,
including hypotheses and theories, as to their strengths and
weaknesses using scientific evidence and information;
– (E) Connect Grade 8 science concepts with the history of
science and contributions of scientists.
• (8.14) Science concepts. The student knows that natural
events and human activities can alter Earth systems. The
student is expected to:
– Predict land features resulting from gradual changes such as
mountain building, beach erosion, land subsidence, and
continental drift;
Earth Systems
Alfred Wagner 1910-1920
• Introduced The
Theory of
Continental Drift
• Based theory on:
– S. America &
Africa
– paleontology
(the study of
fossils)
How do such large continents move?
Arthur Holmes 1930’s
• Introduced supportive theory: Currents of
heat and thermal expansion in the Earth's
mantle move continental plates.
Convection!
Great Global Rift Discovered!
• After WW1 –
Germany found a
mountain-like ridge
that ran through
the Atlantic to the
southwest of Africa.
• Today it is call MidAtlantic Ridge
Harry Hess 1950-1960
• Introduced supportive theory: sea-floor
spreading!
• Different plate movements gave us different
land forms:
– Divergent = divide (Mid-Atlantic Ridge)
– Convergent = come together (Himalaya Mt.
Range or Appalachian Mt. Range)
– Transform = sliding (San Andres Fault)
Seismology
• Seismology is the study of earthquakes.
• Check out the data below that shows where
most earthquakes occur.
Volcanology
• The Pacific Ring of Fire is an area of frequent
earthquakes and volcanic eruptions.
Plate Tectonics Theory
• Developed from
– Puzzle piecing of the continents
– Paleontology (the study of fossils)
– Convection (movement of heat)
– Great Global Rift (aka Mid-Atlantic ridge)
– Sea-Floor Spreading
– Seismology (the study of earthquakes)
– Volcanology (the study of volcanoes)
But….
• What if everything I told you was old and
scientists have created a new theory?
• This new theory is not completely accepted,
but how easily do people accept change?
• Keep in mind that our Earth is a celestial body
and star characteristics might not be to far off.
http://www.youtube.com/watch?v=VjgidAICoQI&feature=related
http://www.newgeology.us/