Module 3

Plate Tectonics


In this module, you will be introduced to a fundamental theory in geology: Plate Tectonics. You will learn about the important hypotheses that eventually led to the development and acceptance of the plate tectonics theory over the last century, including Alfred Wegener’s hypothesis of continental drift and Harry Hess’ hypothesis of sea floor spreading. You will also learn about the key drivers of plate movement and the tectonic processes at work at plate margins. We will revisit this topic many times during the semester.

A theory is a well-supported explanation for a natural phenomenon that still cannot be completely proven. A Grand Unifying Theory is a set of ideas that is central and essential to a field of study such as the theory of gravity in physics or the theory of evolution in biology. The Grand Unifying Theory of geology is the theory of Plate Tectonics, which defines the outer portion of the earth as a brittle outer layer that is broken into moving pieces called tectonic plates. This theory is supported by many lines of evidence, including the shape of the continents, the distribution of fossils and rocks, the distribution of environmental indicators, as well as the location of mountains, volcanoes, trenches, and earthquakes. The movement of plates can be observed on human timescales and easily measured using GPS satellites.

Plate tectonics is integral to the study of geology because it aids in reconstructing earth’s history. This theory helps to explain how the first continents were built, how oceans formed, and it even helps inform hypotheses for the origin of life. The theory also helps explain the geographic distribution of geologic features such as mountains, volcanoes, rift valleys, and trenches. Finally, it helps us assess the potential risks of geologic catastrophes such as earthquakes and volcanoes across the earth. The power of this theory lies in its ability to create testable hypotheses regarding Earth’s history, as well as predictions regarding its future.

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Aerial view of the Himalayas GPS monitor on a stand sitting on top of a mountain, overlooking another range of mountains uplifted mountain range sunrise over a mountain range and valley

Module Objectives

At the completion of this module you will be able to:

  1. Describe the development of the theory of plate tectonics, including the concepts of seafloor spreading and continental drift.
  2. Name the three types of plate boundaries, describe the type of motion, and describe the features associated with each.
  3. Explain the distribution and origin of most volcanoes, earthquakes, young mountain belts and major seafloor features.

Activities Overview

See the Schedule of Work for dates of availability and due dates.

Be sure to read through the directions for all of this module's activities before getting started so that you can plan your time accordingly. You are expected to work on this course throughout the week.


Physical Geology by Steven Earle

Discussion 2 - Plate Tectonics

30 points

This week we will be having a conversation about plate tectonics and the ways in which the hazards associated with movement of the plates might personally affect you or your family. Now that you have completed Module 3 (Plate Tectonics), you should have some basic knowledge about the subject and can make educated post(s).

Discussion 2 Instructions

Pay close attention to the Course Schedule for when each of your posts are due. Some are due earlier than others. Failure to post on time will result in lost points.

Module 3 Assignment: Using Google Earth to Visualize Plate Boundaries

10 points

After you complete the reading, you can start working on Module 3Assignment: Using Google Earth to Visualize Plate Boundaries

Module 3 Quiz

10 points

Module 3 Quiz has 10 multiple-choice questions and is based on the content of the Module 3 readings and Assignment 3.

The quiz is worth a total of 10 points (1 points per question). You will have only 10 minutes to complete the quiz, and you may take this quiz only once. Note: that is not enough time to look up the answers!

Make sure that you fully understand all of the concepts presented and study for this quiz as though it were going to be proctored in a classroom, or you will likely find yourself running out of time.

Keep track of the time, and be sure to look over your full quiz results after you have submitted it for a grade.

Your Questions and Concerns...

Please contact me if you have any questions or concerns.

General course questions: If your question is of a general nature such that other students would benefit from the answer, then go to the discussions area and post it as a question thread in the "General course questions" discussion area.

Personal questions: If your question is personal, (e.g. regarding my comments to you specifically), then send me an email from within this course.