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Problem Set 4.9: Continental Jigsaw Puzzle Activity Instructions: Read
pages 308 to 326 in your text and answer the questions that follow. |
One of the first
pieces of evidence that suggested to scientists that the configuration
of the Earth's tectonic plates was not always as it is today is that some of
the continents which are now separated can be fitted together like a jigsaw
puzzle. For example, if one were to close the Atlantic Ocean, the
western bulge of Africa fits nicely into the embayment on eastern side of the
Americas North stretching from Nova Scotia to Brazil.
Other evidence suggesting that continents have wandered includes the distribution of ancient glacial deposits and ice scour structures (sometimes indicating ice flow direction) and distribution of continental fossils such as the fern Glossopteris and the lizard Mesosaurus in the southern continents of the Earth. In this exercise, the use of geological evidence in the reconstruction of continental configurations in the past is demonstrated.
About 200
million years ago, the southern continents formed the supercontinent
"Gondwanaland." Shortly before this time, Gondwanaland
was attached to an even larger supercontinent called "Pangaea"
that included the southern and northern continents of present-day Earth.
Procedure:
- Cut out the Atlantic Ocean from
diagram 1 and see how well North and South America fit with Europe and
Africa. Paste the pieces in the area provided.
- Cut out the continents from diagram
2 provided and fit them together to form a single landmass based on
evidence provided by fossils and ice flow indicators (note that the
glaciations was centered on the South Pole and spread outward from that
point). Paste the pieces in the area provided. Remember
to paste the key on to your diagram as well.
Conclusion:
- What are the pieces of evidence that
suggested that the continents were once joined but later drifted apart to
their present day location?
Rock structures and glacier
effects.
- Would it be possible for the above
evidence to exist if the continents were not originally joined together?
Yes, but would be it would
be difficult.
