Where is the carbonate on Mars?
In-Class Activity 2_Water World
Julia Kahmann-Robinson PhD and Marjorie Chan PhD, University of Utah Department of Geology & Geophysics
Expose students to the carbon cycle on Earth and how carbonate rocks are created. Students will develop a line of evidence or explanation for the reasons why carbonate rocks are not abundant on Mars.
- Depending on your mode of delivery (in class versus perhaps a homework setting), load the Image File .ppt for the class and make sure you have an Internet connection to view the associated videos.
- Find 3 specimens of carbonate rocks (micrite, coquina, grainstone/packstone, or chalk) or use Image File to show 3 specimens of carbonate rocks.
- Have JMARS available to view carbonate minerals maps of Mars, as well as MOLA maps for geographic context (see Image file in Resources of module shell).
Have students observe 3 different carbonate rocks and ask the following:
- What are the similarities between these rocks? [color, skeletal grains, texture etc.]
- Where might these rocks have been deposited and form? What is your evidence? [If students suggest marine, ask why it could not be terrestrial, lacustrine, or fluvial? Use leman terms if necessary for these environments]
Forming carbonate rocks on Earth
Have students brainstorm how carbonate rocks are formed. Write their ideas on the board.
Watch the following NASA video entitled "Keeping up with Carbon": http://www.youtube.com/watch?v=FgEZpX3n5mo
- How does the student's "formation" history compare/contrast with the video?
- What elements of the video's content exist/do not exist on Mars?
Carbonate rocks on Mars
Bring up JMARS maps of carbonate rocks for students to view the extent (or lack thereof) of carbonate rocks.
- Where are the carbonate minerals most common?
- Discuss why carbonate minerals are not common on Mars.
Carbonates – a class of sedimentary rocks composed primarily of carbonate minerals ranging from calcite to dolomite.
Consider the biosphere, lithosphere, and current atmospheric conditions of Mars at present.
- What would students need to change about Mars today for Mars to be conducive to carbonate development?
- Answers can be elaborately crazy, i.e. put petroleum-powered cars on Mars and create vast amounts of CO2 emissions or if possible move Mars closer to the sun so that it isn't so cold....etc.
Present Figure 1 of Mars (for a full resolution image see the Image File for this module) and ask students the following questions:
In this hypothetical situation (although real imagery)
- Where might you find carbonates? [Have students approach the board/screen and point to areas; along channels or within crater basins]
- What is the basis for their decision? [any water environment might have the potential]