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 structuresMountain 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 drift3) 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 EarthCrust: Outer most layer. Made of solid brittle

rockLithosphere: Contains the crust and the

uppermost mantle. Made up of the tectonic plates

Layers of the EarthCrust: Outer most layer. Made of solid brittle

rockLithosphere: 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 EarthCrust: Outer most layer. Made of solid brittle rockLithosphere: Contains the crust and the uppermost

mantle. Made up of the tectonic platesAthenosphere: found above the upper mantle. Made

up of partly molten rock Mantle: the thickest layer on the earth. Broken into

two parts upper and lowerUpper 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