please get your science notebook and get out your plate boundaries map and worksheet from friday

21
•Please get your science notebook and get out your plate boundaries map and worksheet from Friday. GOOD AFTERNOON!

Upload: lynn-hensley

Post on 26-Dec-2015

215 views

Category:

Documents


2 download

TRANSCRIPT

• Please get your science notebook and get out your plate boundaries map and worksheet from Friday.

GOOD AFTERNOON!

Chapter 9: Plate Tectonics Review

From the Earth’s Crust to the Inner Core:Depth IncreasesPressure IncreasesTemperature Increases

Layers of the Earth

Temp.(°C)

Elements

Crust 0- 860 Oxygen, silicon

Mantle 870 Iron, magnesium

OuterCore

2200 Iron, nickel

InnerCore

5000 iron

Asthenosphere

• The asthenosphere is the semi-rigid part of the middle mantle that flows like hot asphalt under a heavy weight.

• The tectonic plates float on this semi-liquid layer.

Lithosphere vs. Asthenosphere

Lithosphere= rigidAsthenosphere= semi-soft

Convection

• Heated water is less dense therefore rises while cooled water is more dense, which sinks.

• This is also true with air and other fluids.

Alfred Wegener’s hypothesis on Continental Drift

• Evidence from Landform• Evidence from Fossils• Evidence from Climate

All the continents had once been joined in a single landmass, called Pangaea, and have since drifted apart.

Evidence of Continental Drift A mountain range lines up between Argentina in South America and

Africa. Fossils of the reptiles Mesosaurus and Lystrosaurus have been found in

places now separated by oceans. Fossils of the fernlike plant, Glossopteris, have been found in rocks in

Africa, South America, Australia, India, & Antarctica. Deep scratches in rocks show that continental glaciers once covered South

Africa.

Pangaea

• A supercontinent, meaning “all lands”, that existed about 300 million years ago.

Sea-Floor SpreadingTheory

As the plates diverge, molten material rises from the mantle and erupts along the mid-ocean ridge.

Image: A diver swims between the Eurasian and North American plates in Thingvellir lake, Thingvellir National Park, Iceland. Iceland is one place where a mid-ocean ridge can be seen on land and in shallow waters.(credit: Wild Wonders of Europe/Lundgre

http://www.bbc.co.uk/science/earth/surface_and_interior/mid_ocean_ridge

Cause of Deep Ocean Trenches

• When an ocean plate collides with a continental plate, the plate is subducted under the continent.

• Subduction – when one tectonic plate (oceanic) is pushed underneath another tectonic plate.

Transform Boundaries

• Plate boundary where two plates slip past each other, moving in opposite directions.

• Earthquakes frequently occur along these boundaries.

• Creates a fault

Earthquakes

• Occur usually when 2 plates slide past each other, however, can happen at all plate boundaries.

• Release of energy when the lithosphere suddenly breaks and slides

Ring of Fire

Volcanoes form where tectonic plates meet other plates.