Continental Drift Q&A
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Continental Drift PowerPoint Q&A
1.
What theory did Wegener propose?
Wegener proposed the idea of Pangea and the continental drift.
2.
What is the name for North America and Eurasia combined?
Laurasia.
3.
How many continents combined to form Gondwana?
The five continents combined to form Gondwana are South America, Africa, India, Antarctica,
and Australia.
4.
Looking at the map, describe how India is situated in Gondwana.
India is situated in the central-eastern part of Gondwana. Its east faces the ocean, its north
faces Africa, its west faces Africa, and its south faces Antarctica.
5.
Wegener had excellent evidence for Pangea. How does the jigsaw puzzle work? Be sure to
give an example from the map.
The jigsaw puzzle evidence involved matching coastlines and geological features on different
continents. For example, South America’s east coast fits Africa’s west coast.
6.
Looking at the diagram for the jigsaw puzzle, what is a continental shelf? (You can even
Google questions if you get stuck.)
A continental shelf is a submerged portion of a continent that extends the landmass.
7.
Roughly what percentage of Pangea was continental shelf? Hint: Look at light green versus
dark green areas and give a rough %.
20%.
8.
How does finding fossils of Mesosaurus in both South America and Africa prove continental
drift?
Mesosaurus is a freshwater reptile, and its fossils were found in South America and Africa.
However, it could not have swum across the saltwater Atlantic Ocean, so evidence indicates
the continents were connected at one point.
9.
Which of the fossils is an early mammal, though still evolving from a reptile?
An early mammal, though still evolving from a reptile, is Cynognathus.
10.
Coconuts can float across open oceans, so why couldn’t the Glossopteris seeds?
Glossopteris is an ancient family of seed ferns, and its seeds were too heavy to float across
the ocean.
11.
How did geologists match the Caledonian and Appalachian mountains?
Geologists matched the Caledonian and Appalachian mountains by comparing their geological
features and rock formations, finding similar faults, folds, fossils, and ages.
12.
According to the matching rock map, what other African and European mountain belts
formed during Pangea?
The Caledonide Belt, Mauritanide Belt, and Variscan Belt formed during Pangea.
13.
What caused the mountains to form when Pangea assembled?
Mountains formed when Pangea assembled due to tectonic collision.
14.
What are the two puzzling patterns on the world map for ancient glaciers?
1)
Glaciers appear to move out of the water onto land in South America and Australia,
but glaciers only form on land.
2)
Glaciers moved across India and Africa, but these continents are too warm today for
substantial ice sheets.
15.
If you place stakes on top of a glacier and return a year later, they won’t be in the same
place. What do all glaciers do?
All glaciers move.
16.
What two continental ice sheets exist today?
The Greenland and Antarctic continental ice sheets exist today.
17.
What type of glaciers does California have today?
Mountain (alpine) glaciers.
18.
What force changes snow to glacial ice?
The process that changes snow to glacial ice is driven by the pressure of new snow falling
each year on top and pressing downward.
19.
What are two ways that snow changes when it converts to glacial ice?
Snowflakes are compacted into ice granules, then firn, then glacial ice.
20.
What are two ways that glaciers can move?
Glaciers can move downhill by gravity or out in a radial direction.
21.
Looking at the pictures of mountains, glaciers, and continental ice sheets, which one do you
think can flow by both gravity and radial flow?
Glaciers can flow by both gravity and radial flow.
22.
What causes glacial ice to look so dirty on some parts of glaciers?
Mountain (alpine) glaciers move downhill by gravity. The ice is filthy because it is loaded with
boulders and sand as it goes downhill.
23.
What prevents sea ice from growing thousands of feet thick?
Cold polar air freezes the sea surface during the winter, but since ice is a good insulator, the
freezing process stops after a few feet. Warmer ocean currents move under the ice and
prevent the freezing process from extending deeper after a thin veneer of ice forms.
24.
Where do all glaciers originate from?
Recrystallized snow.
25.
What are the two ways that glacial ice erodes rock?
Glacial ice erodes rock through abrasion and freeze-thaw.
26.
Why are glaciers called nature’s bulldozers?
Glaciers break down, pick up, and move vast amounts of rock for great distances.
27.
What new rock forms when glaciers bulldoze the rubble they created?
Tillite.
28.
If glacial ice is soft, how did it carve the deep grooves in Kelly’s Island?
Kelly’s Island was covered in ice, with large boulders frozen into the ice. The boulders ripped
through the soft rock limestone to create the channel grooves.
29.
How do rocks reveal the direction in which a glacier moves?
Through chatter marks, striations, scratches, and polish
.
30.
How do glaciers polish rocks?
The sand and gravel frozen into glaciers can polish rocks.
31.
Briefly restate the two puzzling pieces of evidence that glaciers left.
1)
Glacial evidence near the equator in regions that are now tropical.
2)
Glacial evidence in southern Gondwana. For example, glacial grooves and striations in
warm, dry southern Australia prove it used to be in the South Pole.
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32.
In your own words, restate how Wegener used Pangea to explain how the glacial evidence
makes sense.
The continents were joined to allow ice sheets and glaciers to flow across the land. He used
the concept to explain how glacial evidence could move across the now-separated continents.
33.
What are the three main climate belts on Earth?
Tropical warm and wet at the Equator; Deserts on the western edge of continents at 30°N and
30°S; and Polar.
34.
Where was West Virginia during Pangea, and how does Wegener know that?
Wegener knew that West Virginia was at the Equator during Pangea because the climate belt
says the thick coal beds in W.V. are found only in the wet tropics of the Equator.
35.
If they mine salt today underneath Detroit, where was it located during Pangea?
Detroit was further south in a desert climate at 30° during Pangea.
36.
What latitudes are deserts generally found at?
Deserts are on the western edge of continents at 30°N and 30°S.
37.
According to the climate belt map, which belt were India, Australia, and Antarctica closest
to during Pangea?
The desert belt.
38.
What was Wegener lacking in his attempt to prove continental drift?
Wegener had no mechanism to move the continents.
39.
Briefly, what two ridiculous arguments did Wegener try to provide to show forces moving
continents?
1)
The centrifugal force of the Earth spinning caused it to throw the continents.
2)
The gravitational pull of the Sun and Moon pulls the continents.
40.
Where did the crucial evidence to prove Wegener was right come from?
It was underwater, on the sea floor.
41.
When using sonar, what two measurements are taken with instruments to calculate the
depth of the water?
Travel time and speed of sound.
42.
Which scientist is credited with first mapping the seafloor in detail with sonar?
Harry Hess.