This is a partially developed activity description. It is included in the collection because it contains ideas useful for teaching even though it is incomplete.

Exploring Marine Carbon Isotope Excursions

David Jones, Geology Department, Amherst College

Topic: stable isotopes, geochemistry, oceanography, carbon cycle
Course type: Upper level undergraduate course


The exercise is designed to introduce students to carbon isotope systematics of the long term global carbon cycle. Students would learn about the major sources and sinks in the geologic carbon cycle and the isotopic fractionations associated with key fluxes. Students will explore how perturbations to the carbon cycle affect the isotopic composition of inorganic and organic carbon in ancient sedimentary rocks.

Learning Goals or Outcomes

  1. Identification of sources, sinks, and fluxes relevant to the geologic global carbon cycle.
  2. Ability to predict direction, timing, and relative magnitude of changes in the system due to various perturbations.

How would you assess whether those goals have been met?

Students would build the model and run a few prescribed experiments. Then they would be asked to make predictions for several additional experiments and reconcile the model outcome with the logic of their predictions. Finally, students would be asked to extend the model on their own or develop a new set of experiments not previously addressed.


Kump and Arthur. Interpreting carbon-isotope excursions: carbonates and organic matter. Chemical Geology (1999) vol. 161 pp. 181-198.

Preliminary Model

Preliminary STELLA model for carbon isotopes ( 86kB Nov30 10)