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SEA FLOOR SPREADING

SEA FLOOR SPREADING. TURN AND TALK. With a partner, imagine you are in a submarine. What do you think the sea floor looks like? What do you see? Have you ever seen a picture of the sea floor or watched a video about it?

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SEA FLOOR SPREADING

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  1. SEA FLOOR SPREADING

  2. TURN AND TALK With a partner, imagine you are in a submarine. What do you think the sea floor looks like? What do you see? Have you ever seen a picture of the sea floor or watched a video about it? If not, predict what you think the sea floor might look like. Be prepared to share with the group.

  3. MAP OF THE SEA FLOOR • Notice the mountains that seem to be right in the middle of the ocean. • What can you infer about the ocean floor based on this observation? Mid-Ocean Ridge System

  4. THEN AND NOW • According to studies by geologists, the Earth has not always looked the way it does now.

  5. Pangaea (Greek, meaning ‘all lands’) Positions of the continents approximately 200 million years ago

  6. COMPARE AND CONTRAST Positions of the continents approximately 200 million years ago

  7. EARTH IS MADE OF PLATES Types of Plates • Divergent - plates move away from one another • Convergent – plates move toward one another • Transform – plates move horizontally past one another

  8. Paleomagnetism– the study of Earth’s magnetic field as recorded in ancient rocks

  9. POLARITY Earth has 2 magnetic poles, North and South. Normal Polarity– exhibited by rocks with magnetic minerals which ‘point’ towards today’s position of the magnetic north pole. Reversed Polarity– exhibited by rocks with minerals which ‘point’ towards today’s position of magnetic south.

  10. SEA FLOOR SPREADING ACTIVITY • Break into groups of 3 or 4 • Label yourselves A, B, C, or D • A and B-you will pull the pieces of paper • C-you will use one color marker to color in the middle of the paper for normal polarity. • D-you will use another color marker to color in the middle of the two papers for reversed polarity

  11. Sea Floor Spreading Results • Look at your sea floor map. Label the parts of normal polarity and reversed polarity. • Label the rift zone. • Label where the oldest and youngest rocks might be located. • Turn in your map with your names on the back when you are finished.

  12. Sea Floor After Normal Polarity

  13. REVIEW On an index card, briefly describe how the sea floor spreads. Remember to use your vocabulary words: tectonic plates, magma, divergent plates, normal and reversed polarity. On the back of your index card write one thing you are still confused about or would like more information about.

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