The Mid-Ocean Ridge
What is Sea-Floor Spreading?
3 Types of Evidence
Subduction at Trenches
Miscellaneous
100
Name the area where the mid-ocean ridge rises above the ocean's surface.
Iceland
100
What was the name of the American geologist that discovered sea-floor spreading?
Harry Hess
100
Name the three types of evidence that supported sea-floor spreading.
Evidence from molten material, magnetic stripes, drilling samples
100
What is the difference between a deep-ocean trench and the mid-ocean ridge?
Deep-ocean trenches destroy oceanic crust, and the M.O.R. creates it.
100
What is the best subject in school?
Science!
200
What is sonar?
a device that bounces sound waves off underwater objects and then records the echoes.
200
During what year did Henry Hess think of the idea of sea-floor spreading?
1960
200
What was the name of the drilling ship that provided evidence for seafloor spreading?
The Glomar Challenger
200
What is subduction?
Subduction is the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle.
200
What is the name of the super-continent that we learned last week?
Pangaea
300
What flows out of the mid-ocean ridge and immediately cools when it comes to contact with the water?
Magma
300
What can the ocean floors be compared to according to Hess?
The ocean floors were like conveyor belts that move the continents!
300
Can you describe what the magma looked like when the 'Alvin' observed it?
The magma was pillow-shaped or like toothpaste just squeezed out of a tube.
300
What is happening to the Atlantic Ocean? Why?
The Atlantic ocean is expanding, because it has more mid-ocean ridges.
300
Name two of the states affected by the recent tornados.
Indiana, Alabama, Kentucky, Mississippi, Arkansas, Tennessee, Oklahoma
400
What sea creatures can be found near the mid-ocean ridge?
Giant clams, red-tipped tube worms, spider-like crabs
400
What theory did seafloor spreading give evidence for?
Continental Drift
400
When did the last reversal of the poles take place?
780,000 years ago.
400
What is happening to the Pacific ocean?
The Pacific ocean is getting smaller, because it has more deep trenches.
400
What is Mr. Nguyen going to school for?
To become a teacher
500
In the book or powerpoint, what is a good example to compare the mid-ocean ridge to?
Mid-ocean ridges curve like the seam of a baseball along the sea floor.
500
List the 3 main steps in sea-floor spreading.
1. Molten material rises along the mid-ocean ridge, forming new crust. 2. The sea-floor spreads apart along both sides of the M.O.R. 3. The ocean floor moves like a conveyor belt, carrying the continents along with it.
500
How did the scientists determine the age of the rocks that they drilled and pulled up?
The further away they were from the ridge, the older the rocks were.
500
Explain why the ocean floor is "renewed" every 200 million years.
It takes 200 million years for new rock formed along the mid-ocean ridge to reach a deep ocean trench, where it is destroyed.
500
What's Mrs. Hankins' favorite football team?
The Denver Broncos
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