Week 2: Introduction to Plate Tectonics

Part I (continued): PLATE TECTONIC THEORY.

Watch this short video from the Jason Project for a brief (15 minutes) overview of plate tectonics.

Example questions:

• Do most earthquakes occur in the middle or near the edges of tectonic plates?
• See the USGS Earthquake Activity page for recent earthquake locations.
• What are the three type of plate boundaries?

Here is a link to a page that has a great explanation of density, buoyancy, isostasy, and the structure of the Earth's interior from the University of Michigan. Scroll down and try out the density/buoyancy demo.

This page at the University of Nevada has a great explanation of the Earth's interior, and an explanation of the seismic evidence.

Part II. The composition of the Earth and its internal structure:

• What is the most abundant (in terms of weight %) element in the whole Earth?
• What is the most abundant (in terms of weight %) element in the Earth's crust?
• What are the compositional layers that make up the Earth?
• What are the mechanical layers inside the Earth?

<-- Click on this diagram for a closer view.

It is a generalized diagram that clearly shows the difference between COMPOSITIONAL and MECHANICAL layers within the Earth. You will have to know the layers and the differences between them for the first exam.

Here is a great web site with information about the nature of the Earth's interior.

This story (short video and audio) NPR's Science Friday about the drilling program to drill through the ocean crust and lithosphere.

Here is a study guide for chapter 2 in the textbook.

Watch this video from the Jason Project (OK, it is a little cheesy, but is worth it) for a brief introduction to minerals and rocks.

Answers to the practice questions above:

Earthquakes occur primarily (not exclusively) near the edges of tectonic plates.

The three types of plate boundaries are:

1. Divergent
2. Convergent
3. Transform

The most abundant element in the Earth (in terms of weight %) is Iron.

The most abundant element in the crust (in terms of weight %) is Oxygen.

See the diagram above for the compositional and mechanical layers inside the Earth.