Introduction to Plate Tectonics

Introduction to Plate Tectonics

A recap of Earth's layers and a first look at plate tectonics!

Chemical (compositional layers) = what the layers are made up of

Physical (mechanical) layers = how the layers behave

Chemical Layers

• The crust is the thinnest & least dense layer: oceanic crust is THINNER but MORE DENSE than continental crust! The crust is made of igneous rock containing a lot of silicon and oxygen.

• The Mantle is the middle layer. It is hot softened rock containing iron and magnesium.

• The outer core is a very hot liquid. It is made of iron and nickel.

• The inner core is also made of iron and nickel, but solid

Physical Layers

• Lithosphere - crust + uppermost part of mantle = cool, brittle, solid rock. Broken into pieces called tectonic plates

• Asthenosphere: Hot softened rock with areas of melt. Moves slowly: a solid that behaves like a liquid! "Plasticity"

• Mesosphere - lower part of the mantle

• Outer Core - hot liquid that churns - this generates electrical currents that in turn create Earth's magnetic field!

• Inner Core - spinning solid: most dense layer!

Lithosphere, Asthenosphere & Tectonic Plates

• The lithosphere is broken into tectonic plates

• These plates are not connected - they move slowly around the surface of the earth

• The plates float on top of the asthenosphere

Multiple Choice

The lithosphere includes the _____ and part of the _____.

• core, crust

• mantle, core

• crust, core

• crust, mantle

Multiple Choice

As you travel from the inner core to the crust, how would temperature, pressure and density of the material change?

• The would all increase

• The would all decrease.

• Nothing, the layers are made of the same material throughout

• Temperature would decrease, but pressure and density would increase

Multiple Choice

What type of rock is the crust made up of?

• sedimentary

• igneous

• metamorphic

Multiple Choice

This layer of the crust is thinner but more dense. As a result, it sinks into the mantle and is lower-lying. It is made of basalt (igneous rock).

• Oceanic Crust

• Continental Crust

• Igneous Crust

• Sandwich Crust

Multiple Choice

Which layer has the coolest temperatures?

• outer core
• inner core
• mantle
• crust

Multiple Choice

What is the outer core made of?

• solid rock
• solid metal
• melted rock
• melted metal

Multiple Choice

Which layer is made of solid iron & nickel?

• inner core
• outer core
• mantle
• crust

Multiple Choice

This layer is divided into pieces called tectonic plates.

• Mesosphere
• Asthenosphere
• Mantle
• Lithosphere

Multiple Choice

The core is mostly made up mostly of which elements?

• Oxygen and Silicon
• Silicon and Magnesium
• Nickel and Iron
• Iron and Magnesium

Multiple Choice

This layer is directly below the crust.

• Crust
• Mantle
• Outer Core
• Inner Core