Platetechtonics
Plate techtonics
Continental Drift
The theory discovered by Alfred Wegener that
states the continents were once connected
but later drifted apart to their current
locations.
Evidence supporting continental drift
1) Shapes of the continents
- The continents fit together like a jigsaw puzzle.
The first piece put in place was the Eastern
side of South America and the Western side
of Africa
Evidence supporting continental drift
2) Matching geological structures
Mountain Ranges:
- Mountain Ranges on one continent end at
the coast and appear to continue on a
different continent
Types of rock:
- Similarities between the fold and age of
rocks were found on different continents
Evidence supporting continental drift
3) Matching Fossils:
- The fossils of one species were found on two
separate continents.
-
Of these the most important was a
freshwater reptile found in Africa and South
America(it would not be able to cross the
ocean)
Evidence supporting continental drift
3) Paleoglaciation:
When glaciers move forward or retreat they
leave u-shaped valleys in the earth.
- Many of these were found in tropical parts of
Africa and South America : These places are
now found in the tropics where glaciers
would not form
- The pattern of the glaciers on these
continent only make sense if the continents
were together at some point
Layers of the Earth
Layers of the Earth
Layer of the Earth
Layers of the Earth
Layers of the Earth
Crust: Outer most layer. Made of solid brittle
rock
Lithosphere: Contains the crust and the
uppermost mantle. Made up of the tectonic
plates
Layers of the Earth
Crust: Outer most layer. Made of solid brittle
rock
Lithosphere: Contains the crust and the
uppermost mantle. Made up of the tectonic
plates
Athenosphere: found above the upper mantle.
Made up of partly molten rock
Mantle: the thickest layer on the earth. Broken
into two parts upper and lower
Layers of the Earth
Crust: Outer most layer. Made of solid brittle rock
Lithosphere: Contains the crust and the uppermost
mantle. Made up of the tectonic plates
Athenosphere: found above the upper mantle.
Made up of partly molten rock
Mantle: the thickest layer on the earth. Broken into
two parts upper and lower
Upper Mantle: Made of partly molten rock
containing Fe and Mg (lava the consistency of
toothpaste)
Lower Mantle: Solid dense material also containing
Mg and Fe
Layers of the Earth
Outer Core: A liquid made mainly from iron and
nickel
Inner Core: A solid mixture of mainly iron and
nickel at 5000 – 6000 C. The high pressure
makes it solid