Who's Your Daddy?
The scientist who hypothesized that the continents are in constant motion.
Who was Alfred Wegener?
What was the name of the supercontinent that Wegener said once existed?
What is Pangaea?
The farther away you get from a mid-ocean ridge, is the crust newer or older?
The farther out you go, the older the crust gets. (The newest crust is at the mid-ocean ridge.)
These are underwater mountain ranges.
What are mid-ocean ridges?
What is the smooth seafloor called?
The presence of these on continents that have warm climates suggest that long ago they had very cold climates.
What are glacial grooves?
What is it called when Earth's magnetic field reverses?
What is magnetic reversal?
This device mapped the depth of the ocean floor and found evidence of mid-ocean ridges?
What is an echo sounder?
What is normal polarity?
What was found in Antarctica that suggest that this continent was once near the equator?
What is coal?
If a magnet were to point south, what would this be called?
What is reversed polarity?
How far do continents move each year?
What is 2.5 cm?
This occurs when new oceanic crust forms when magma rises up through cracks in the crust at mid-ocean ridges.
What is seafloor spreading>
What can form when one plate is shoved under another plate on the seafloor?
What are earthquakes and (chains of) volcanoes?
Where did Wegener think most of the continents (even those near the equator now) were located 250 million years ago?
What is near the South Pole?
This theory states that Earth's surface is divided into huge plates of rock that move over Earth's mantle in relation to other huge plates of rock.
What is plate tectonics?
What can form when 2 plates separated on the seafloor?
What are mid-ocean ridges?
The molten rock of the that emerges during seafloor spreading cools and becomes ______.
What is basalt.
What occurs when plates slide past one another?
What are earthquakes?
Name 2 ways fossil evidence supports continental drift.
1. Remains of plants and animals are found on different continents that are now separated by oceans
2. Fossils of plants and animals that lived in wet, warm climates have been found in very cold climates
Why did scientists at the time not believe Wegener's theory?
(1)The continents moved so slowly it was hard to observe.
(2) Wegener couldn't explain what caused the continents to move
How do the magnetic strips on the oceanic crust support seafloor spreading?
The strips (which have magnetic properties) alternate on the seafloor and line up with normal polarity and then reversed polarity, etc. This shows that over time Earth's magnetic field has reversed directions.
How does seafloor spreading help explain continental drift?
It shows that continents move with the oceanic crust as it spreads away from mid-ocean ridges.
What's the largest tectonic plate on Earth?