Soil Formation and Chronology

Soil profile in cinders
Soil profile in cinders

What happens to the landscape after the volcanoes stop erupting? Everything about the area has changed – there are new hills, new lava fields, and much of the old landscape is buried and the vegetation is gone. Nature begins the process of healing and rebuilding and we can study how this happens by looking at the soils. Soils develop as functions of climate, geology, plant and animal life, steepness of slopes – and time. Through the integrated dating and hill slope studies we can apply what geologists call “space for time substitution”. That is, we will look very carefully and document specific properties of soils that have developed on the different aged volcanic landforms. Soils will look very different on a volcano that erupted 1000 years ago from one that erupted 5000 or 20,000 years ago. The soils then are intimately related to infiltration of rainwater, nutrients, and plant communities. Projects for students may include analyzing and describing soil profiles excavated into the surfaces of volcanic landforms; performing laboratory analysis of soil properties such as grain size, salt content, and more. Results of these analyses will form the basis of soil chronosequences that can help determine the rates of landscape changes.