Pangaea and Continental Drift I understand how continents move. I can visualize what the earth looked like in the past. I can identify evidence for continental drift and Pangaea

Colorado—now Look at the picture on page 649 What kind of plants and animals live in Colorado now? What evidence do you see for what the climate is like now? What evidence do you see for what the elevation is like?

Colorado—then Look at the picture on page 643. What kind of plants and animals lived in Colorado then? What evidence do you see for what the climate was like then? What evidence do you see for what the elevation was like then?

Colorado—now and then pg 643, 649 What things are similar between the two scenes? What things have changed? How could this happen? What questions do you have?

CONTINENTAL DRIFT Alfred Wegener was one of several people who thought the continents looked like they fit together, so he proposed the continental drift theory in 1912. Wegener was a meteorologist and astronomer so needless to say other scientists thought he was out of his field of study.

His studies concluded that at one time all the continents were joined together in one land mass called Pangaea.

Define Pangaea… The word Pangaea comes from Greek words “pan” and “gaia” “pan” meaning “entire” “gaia” meaning “earth” Therefore Pangaea literally means “Entire Earth.” Which seems fitting because it was composed of every land mass on the entire Earth!

PANGAEA means “all land” Scientists thought this theory was outrageous because even though Wegener had evidence of one large land mass, he didn’t have the answers to what force (engine) “floated the plates”. He was laughed at and did not live to see his theory accepted. This animation begins with the continents in their present location, and then moving back in time to form PANGAEA. The circles represent fossil evidence that Wegner used to prove his Continental Drift Theory.

WHERE’S THE EVIDENCE Wegener had 5 pieces of evidence to prove his continental drift theory: PUZZLE PIECES: The continents, especially South America and Africa, seemed to fit together like a puzzle.

Do you think they swam all the way across the oceans? NO! FOSSIL EVIDENCE: Wegener noticed that plant and animal fossils were found on different continents. Do you think they swam all the way across the oceans? NO! This would lead people to believe that the continents were once joined. Glossopteris…seed much to large to be windblown Mesosaurus…lived in fresh water and could not have lived in salt water

What is this a fossil of? Where would you expect to find a specimen like this on the planet? Copyright © 2010 Ryan P. Murphy

Answer! This is a fossilized tropical plant found on Antarctica. Copyright © 2010 Ryan P. Murphy

Answer! This is a fossilized tropical plant found on Antarctica. Remember, the continents have moved and Antarctica use to be in a warmer climate. Copyright © 2010 Ryan P. Murphy

“Darn you continental Drift.” Answer! This is a fossilized tropical plant found on Antarctica. Remember, the continents have moved and Antarctica use to be in a warmer climate. “Darn you continental Drift.” “Darn you.” Copyright © 2010 Ryan P. Murphy

3a. ROCK EVIDENCE: Huge belts of rocks found in Africa and South America were identical. Not only were they the same, but they would match up (age, thickness, types) if the continents were put together.

3b. Matching Mountains: The Appalachian Mountains that disappear off the coast of Newfoundland match mountains in the British Isles and Scandinavia which are comparable in age and structure.

WEGENER’S EVIDENCE Mountains Some mountain ranges on different continents seem to match. Ex: ranges in Canada match Norway and Sweden Ex: Appalachian Mtn. match UK mtn

4. GLACIER EVIDENCE: There is evidence that glaciers moved from Africa, through the Atlantic Ocean, and then on towards South America. This would be much easier if the Atlantic Ocean were not there

Glacial Striations…Scratches glaciers leave on rocks as they travel

5. CLIMATE EVIDENCE: Warm weather plants have been found in the Arctic… but it’s not warm there! Glacier deposits have been discovered in tropical and desert locations…it’s not cold there, either! The continents had to have been at different locations in the geological past.

AMAZING EARTH SCIENCE FACTS The pieces of evidence that support Continental Drift are Continents ______________ fit together like puzzle pieces __________ showing the same types of life existed on the now separated land masses Fossils Rock layers & mountains ___________________________match up along coastlines of once joined continents ____________ evidence in temperate and hot climates Glacial

Wegener—credited for Pangaea—concept that all the continents used to be one super-continent Continental Drift—theory of how our continents have moved to where they are now, and how the continents continue to move.

Further evidence to support Continental Drift: Igneous Rock Metamorphic Sedimentary Further evidence to support Continental Drift: If you learned about the rock cycle you learned that rocks can be made by the heat from the earth melting them down to make new rocks. Minerals in the rocks that respond to magnets cool down and position themselves to point to magnetic North Since we see that minerals in the earth are not oriented to magnetic North, we can conclude that the change in magnetic orientation is a result of continental drift.

Satellites are now used to measure the movement of continents Evidence of Continental Drift Satellites are now used to measure the movement of continents Laser Geodynamics Satellite (LAGEOS)

The speed at which the plates move is about the speed at which your fingernails grow. Copyright © 2010 Ryan P. Murphy

In 1915, The German geologist Alfred Wegener (1880-1930) proposed continental drift. Copyright © 2010 Ryan P. Murphy

In 1915, The German geologist Alfred Wegener (1880-1930) proposed continental drift. Not accepted until the 1950’s! Copyright © 2010 Ryan P. Murphy

In 1915, The German geologist Alfred Wegener (1880-1930) proposed continental drift. Not accepted until 1950’s! “I say.” “Africa and South America fit strangely like two puzzle pieces.” Copyright © 2010 Ryan P. Murphy

?????????? ONE QUESTION REMAINED ?????????? WHAT FORCE WAS MAKING THE CONTINENTS MOVE (in fact, that question was why Wegener’s theory wasn’t accepted) ?