1. Bellringer 10/31/16 Make a Cornell notes data sheet.
Don’t write the types of matter and solids, liquids, gases….
Etc…

2. 17.1 Continental Drift

3. Background Maps! Explorers, such as Columbus
and Magellan, began to sail
the earth and brought back
information that was made into maps
These maps showed a curious outline.
The edges of the continents looked like they should fit together like a puzzle!

4. Continental Drift Alfred Wegener- first proposed hypothesis
Early 1900s
Published The Origin of Continents and Oceans
Pangaea = “all lands”
Panthalassa = “all seas”

6. Continental Drift Super-continent, Pangaea, began breaking apart
200 million years ago, Mesozoic Era
Continents “drifted” to current positions
Continents “broke” through the ocean crust
Crumpled to cause mountains

11. Evidence
1. Jigsaw puzzle – how the continents fit together

12. Evidence 2. Fossils Mesosaurus (dinosaur), Glossopteris (plant)
Found at the edges of two vastly separated continents

15. Evidence 3. Ancient climates Areas that have glaciers
today show evidence
of being near
the equator at one time.
The coal fields in
Kentucky formed
in a tropical area.

17. Evidence
4. Rock Types
Similar rock types on continents on opposite sides of the Atlantic Ocean.
Similar, age, structure and rock types are found in the Appalachian Mountains and mountains in Scotland and Scandinavia.

18. Rocks
When the continents are reassembled, the mountain chains from a continuous belt

20. Proved? Wegener was unable to provide mechanism to prove hypothesis
Evidence now
Paleomagnetism
Earthquake patterns
Ocean drilling
Hot spots

21. Evidence Today Mid-Atlantic Ridge Undersea mountain range
Scientists brought rocks up from the ocean floor
Much younger than the rocks from the continent
Oldest oceanic rock = 175 million years old
Oldest continental rock = 4 billion years old

22. Evidence Mid-Atlantic Ridge Hess proposed hypothesis
At the center is a break, or rift, in the crust
The rift is moving apart
Trenches = deepest parts of the ocean
The deepest trench, the Marianas Trench, is more than 11 km deep

23. Evidence Seafloor spreading
Molten rock (magma) seeps through forming new ocean crust
Dietz gave it the name

24. Evidence Paleomagnetism
the Earth’s magnetic field switches orientation
Produces magnetic “stripes” in the new rock along the ocean floor

25. Paleomagnetism As magma solidifies to form rock
Magnetic field aligns and becomes permanent
Normal polarity points North
Reverse polarity points South

26. Paleomagnetism Some rocks showed reverse polarity
Scientists discovered periods of reversed magnetic field on Earth
Patterns on ocean floor
Mirror images

28. Plate Tectonics
The evidence supporting Continental Drift has caused scientists to look more at what makes up the Earth
This thinking takes us to Plate Tectonics

29. In-Class Assignment/Homework