Historical Figures • Late 1500s Abraham Ortelius was the first one to imagine the continents were joined together before drifting to their present positions. • 1620s Sir Francis Bacon noticed that the coastlines of South America and Africa were similar. • Late 1800s Eduard Suess, an Austrian Geologist, was the first to realize that South America, Africa, India, Australia, and Antarctica were connected at one point. He named the large landmass Gondwanaland which contained all the southern continents.
Transcript
Historical Figures• Late 1500s Abraham Ortelius was the first one to
imagine the continents were joined together before drifting to their present positions.
• 1620s Sir Francis Bacon noticed that the coastlines of South America and Africa were similar.
• Late 1800s Eduard Suess, an Austrian Geologist, was the first to realize that South America, Africa, India, Australia, and Antarctica were connected at one point.
He named the large landmass Gondwanaland which contained all the southern continents.
Alfred Wegener• Born 1880 died 1930
• German Meteorologist
• First to come up with the idea of continental drift because the Earth fit together like a jigsaw puzzle.
• Most notable for his theory of continental drift proposed in 1912. This theory said that the continents were slowly drifting around the earth but he could not demonstrate his theory.•Credited with the Theory of Continental Drift because he provided EVIDENCE!!
•Theory of Continental Drift: States that all the continents were once together and have since moved apart.
Modeling Continental Drift
Part One UNLINED PAPER
• Tear a sheet of unlined paper into seven jagged, unequal pieces.
•Make sure to shuffle the pieces once you have all seven and put them in a pile.
•Next, trade your pile of paper with a partner.
•Now, with a new pile of paper, try to fit the seven pieces of unlined paper back together so that they look like the original sheet of paper.
Part Two NEWSPAPER
• Same procedure as the unlined paper
• Tear the newspaper into seven jagged, unequal pieces.
• Shuffle the pieces up and put them into a pile.
• Trade your pile with a partner. With your new pile of ripped newspaper, try to put the pieces back together like the original sheet.
Modeling Continental Drift
•Pangaea 250 million years ago, all Earth; refers to one supercontinent that contained all the continents we have today.
•Laurasia large landmass that contained the northern continents.
•Gondwanaland large landmass that contained the southern continents.
• The continents didn’t necessarily “fit” together at their ever changing shoreline but rather at the continental shelf.
• Shorelines are eroded much too dramatically to be clear evidence of a perfect match
Fossil Safari
Imagine that you are going on a world-wide expedition to
find fossils of extinct organisms. From the evidence you find,
you hope to obtain a picture of what life on Earth was like about 250 million
years ago.
North America
South America
Africa
Europe
Asia
Australia
Antarctica
A (Yellow)
Glossopteris
B (Orange)
Kannemeyeria
C (Blue)
Labyrinthodont
D (Purple)
Lystrosaurus
E (Red)
Thecodont
F (Green)
Cynognathus
G (Pink)
Mesosaurus
North America
South America
Africa
Europe
Asia
Australia
Antarctica
A
A
A
AA
A
B
B
B
B
B
C
C
C
C
D
D
D
E
E
F
F
G
G
Fossil Evidence• Fossils of various extinct species were found in very unusual modern day places.
•Physically, many of the prehistoric animals simply could not have traveled the far distances.
•Glossopteris, an extinct plant, was found in many unusual modern day climates. The same type of plant cannot exist in such extreme climate variations, supporting continental drift
Rock Sequences
• Many continents in the southern hemisphere exhibited very similar rock and fossil sequences.
• Some similar rock sequences can be found in India, South Africa, South America, Australia, Antarctica, Madagascar, and Falkland Islands
•He named this the “Gondwana Sequence”
Rock Sequences
Similar Geologic Structures
• Geologic structures found in Newfoundland matched up with structures in Ireland, Scotland, and parts of Scandinavia.
• Rock structures in the Appalachian Mountains also matched up with structures in Morocco and Algeria in Africa.
• To the left is a bird’s eye view of the Appalachian Mountain range next to the Atlas Mountains in Morocco.
•Notice anything interesting?
• These two mountain chains were formed by the same chain when they were connected.
Glacial Evidence
• Glaciers are large bodies of ice that form over land.
• Polar Ice Caps are examples from today
• Move very slowly over land when they become heavy enough
• As they move, they deposit rocks and other debris called glacial till deposits
• These rocks and debris can leave behind “scratches” called striations.
Glacial Striations (scratches) were found to match up across the oceans, which strongly
suggested the continents were once attached
• This wouldn’t make any sense… So how could this be so?
…if you push the continents back together, here is what you get…
• Land• Arrows• Continents• Plates• Water• Oceans/Rivers• North is mostly green• Climate• Glaciers• Earth• Movement• Puzzle
Paleo-climate Data• Wegener decided to take his research a step
further and examined ancient climate data.• Particular deposits would designate a particular
Today, these are 30° north or south of equator• COAL AND CORAL Warm, tropical water.
Locate ancient equator• GLACIAL DEPOSITS Locate poles
• Explanation? Either a movement of the plates or a movement of the poles
So Let’s Recap Wegener’s Evidence…
1. FIT He observed that the continental shelves look like they fit together at one point in history.
2. FOSSILS Found fossil remains in very different modern day climates which could only be explained by continental drift. Also, the locations of certain fossils suggested that the continents must have been joined together at one point in history.
4. GLACIERS 250 m.y.a., huge glaciers moved along the continents and left behind scratch marks. When these striations were matched up, they showed that the continents must have been once together.
3. ROCK SEQUENCES/STRUCTURES He found that not only were there similar rock sequences across oceans, but very similar mountain chains and other rock structures.
5. PALEOCLIMATE Glacial deposits, along with other deposits, indicated that the only explanation for the glacial movement was continental drift. Also, other deposits indicated a very different story of what the climate was like in the past.
