Chapter 7

“the present is the key to the past”

Warm-up

• Fossil Continent Puzzle

• Review Far-flung Fossil Activity

Continental Drift

• (1912) Alfred Wegener

• Stated that the continents once formed a single landmass, broke up, and drifted to their present locations

Google Earth Tour

Evidence for Continental Drift

• Shape of the continents

• Fossils found on geographically separate continents

– Mesosaurus: small fresh water reptile

– Glossopteris: plant

– Lystrosaurus: land reptile

Puzzle Activity • Three Mountain Ranges that cross a minimum of three

puzzle pieces

– BROWN

• Create five coal deposits that span two puzzle pieces by drawing oval shapes

– BLACK

• Put a red circle near the middle of your puzzle. From the circle, draw red arrows outward in all directions to the edge pieces.

• Cut up puzzle pieces and give them to someone else to put together

• Rock formations

– Matching mountain ranges (with the same age and structure)

• When Pangaea is reassembled the mountain ranges form a continuous belt

Paleoclimatic evidence • Glaciers in S.A & Africa

• Coal beds in Antarctica

Glacial Abrasions

• A large mass of moving ice that forms or advances by the compacting of snow

• As glaciers move they scratch and abrade the soil and rocks underneath the glacier.

• Glaciers advance and recede from a central location, so the scratches will appear to be going outward from the middle of the glacial abrasions.

NOTE: Glaciers move on land and cannot come out of the ocean onto land.

How Coal is Formed • Coal is made from giant plants that lived

hundreds of millions of years ago in swamp forests.

– Swamps have hot, humid climates.

• When these giant plants and ferns died, they formed layers at the bottom of the swamps. Over thousands of years pressure and heat turned these remains into what we call coal.

• It would be unlikely for coal to be found in Antarctica if it always had the same cold climate.

Wegener Opposed

• He said the continents plowed through the rock of the ocean floor

– No geologic evidence

• Spent the rest of his life searching

– (1930)Froze to death in Greenland while on an expedition