Unit 3Physical Oceanography

UEQ: What geological processes are responsible for the physical features of

the Earth.

Concept 2: Continental Drift and Plate Tectonics

• LEQ’s1. What is the Continental Drift Theory?2. How did scientists develop the Continental Drift

theory?3. What is the theory of Plate Tectonics?4. How does Plate Tectonics relate to the

Continental Drift Theory?

LEQ1: What is the Continental Drift Theory?

• In 1912 a German scientist named Alfred Wegener proposed that all the known continents were once one large continent called Pangaea surrounded by one large sea called Panthalassa.– These words come from Greek words.• Gaea is the Greek Goddess of Earth• Thalassa means sea• Pan means all

PB

• What does Pangaea mean in Greek?• What does Panthalassa mean in Greek?

LEQ1: What is the Continental Drift Theory?

• Wegener looked at maps and saw that the continents seemed to fit together like puzzle pieces.– He proposed that the continents were drifting apart

by floating on the mantle and had been drifting apart for 200 million years.

– 100 Greatest Discoveries: Continental Drift

LEQ2: How did scientists develop the Continental Drift Theory?

• Evidence to support Continental Drift:– Fossils of the same animals and plants have been found

on continents that are not currently connected but would have been in Pangaea.

LEQ2: How did scientists develop the Continental Drift Theory?

– Rock Layers on one continent line up with rock layers on other continents that would have been connected in Pangaea.

LEQ2: How did scientists develop the Continental Drift Theory?

– Mountain Ranges that are the same size, age, and rock types spread across more than one continent without continuing under the ocean.

LEQ2: How did scientists develop the Continental Drift Theory?

– Glacier evidence is found on multiple continents, some of which are located in regions that the glaciers should not have reached, unless the glacier happened on Pangaea.

Rally Robin Write

• List the 5 pieces of evidence for the Continental Drift theory.– Who ever is younger A or B begins.

• Once you have listed all five pieces of evidence, write down whether you feel this is enough evidence to support this theory and justify your answer.– Share with your partner, this time whomever is

older goes first.

LEQ2: How did scientists develop the Continental Drift Theory?

• Even with all of this evidence to show that Pangaea had indeed existed, Wegener could not fully explain how the continents were moving.

• Without an explanation for how Continental Drift was occurring, the scientific community rejected this theory.

LEQ 3: What is the theory of Plate Tectonics?

• During the same time period as Wegener, new technology was being created that allowed scientists to “see” the sea floor.– SOund Navigating And Ranging = SONAR– This allowed maps to be made of the sea floor.

• Technology continued to improve through World War II.

LEQ 3: What is the theory of Plate Tectonics?

• In 1960 two scientists used the SONAR data and were able to determine that the sea floor is constantly spreading in some regions and being recycled in others.

• 100 greatest Discoveries: Sea Floor Spreading

Yay or Nay

• A’s: You believe that the idea of sea floor spreading is important to the Continental Drift theory. State your case and justify it to B.

• B’s: You think that the idea of sea floor spreading has nothing to do what so ever with the Continental Drift theory. Argue your case in response to what A stated.

• A’s: One more chance to argue your case against B.

LEQ 3: What is the theory of Plate Tectonics?

• The theories of Continental drift and the information of Sea Floor Spreading were combined into the theory of Plate Tectonics.– The theory of Plate Tectonics states that Earth’s crust is

split in many plates that flow along the mantle. These plates can move in three ways:• Towards each other = converging• Away from each other = diverging• Sliding past each other = transforming

– There are 52 total plates, 14 major and 38 minor

Diverging

Converging

Transforming

Bill Nye Plate Tectonics Demonstration