Mars for Earthlings > Lesson Modules > In-Class Activity 1-Lava flows

Lava Flows

In-Class Activity 1_Olympus Mons & Igneous Rocks

Julia Kahmann-Robinson PhD, University of Utah Department of Geology & Geophysics


Recognize a pahoehoe vs. A'a' lava flow through video, explain why the flows differ, and hypothesize which flow might be more common on Mars.



  1. Have students watch both the Pahoehoe and A'a video (see Resources above in this In-Class Activity). As they are watching, have them record their observations of each flow and how they differ.
  2. Discuss student observations of these Earth examples and make corrections where necessary.


  1. Ask students which lava flow, both or neither, would be more common to Mars. Encourage students to substantiate their answers.
  2. Following discussion of the above, present Figure 1 and ask what type of lava flow is most likely to have formed the spiral feature (see Image File for higher resolution and original image size)


Divide the class into two teams (one Pahoehoe, the other A'a) and give them the basic physical characteristics of the two lava types. Their job is to research (e.g. on the internet) what causes the different physical properties (WHY the two types of lava are different). They should explain how different fluid properties, such as viscosity and crystal and gas bubble content, affects their type of flow. Each team can give a short presentation of their lava.

Below is a brief overview of each lava type:


Of the rocks pictured in Figure 2

  1. Which are most likely to have formed by igneous processes on Earth?
  2. Which by igneous processes on Mars?
  3. Make sure students explain their choices in discussion. Hide caption from students. **The .ppt Image File does not have descriptions


Consider the Spirals in Athabasca Valles (Figure 1). Which rock(s) in Figure 2 would you expect to find in Athabasca Valles? Why?

Consider the Spirals in Athabasca Valles (Figure 1), which rock(s) in Figure 2 might be found there?