Week 2: Introduction to Plate Tectonics

Part I (continued): PLATE TECTONIC THEORY.

Water plays an important role in the formation of magmas and plate tectonics. Yet historically, minerals in the mantle have thought not able to contain significant amounts of water. Here is a short video about one of the top researchers in the world, Steve Jacobsen, and his long pursuit to discover how much water is in the mantle:



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.

Related to our discussion about sea level-change and subsidence of Earth's crust in the Mississippi Delta region, check out this site..

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:

 

 

<-- 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.

The whole solid mantle moves very slowly due to convection.

 

Example questions:

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.

 

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