Gaia Stucky de Quay at University of Texas at Austin.
Introduction
Impact craters are important aspects of the landscape on most rocky planetary bodies. The attached presentation introduces the importance of considering impact cratering and the basic formation and resulting morphology of a crater. The associated lab introduces the fundamental concepts of impact cratering distribution and morphology, and how we can recreate the observed distribution and morphology in models, after ideas published by Howard (2007). After investigating impact cratering itself, this lab moves on to explore the roles of diffusion and advection in modifying the cratered surface, using Landlab model components to explore the evolution of cratered landscapes over time.
Classroom organization Although we understand the process of cratering reasonably well we have a limited understanding about how cratering and the cratered surface influences the role of other longer-term surface processes. For example, on heavily cratered surfaces of the Moon, Mars, and Mercury, which have not been altered by plate tectonics like on Earth, how do the craters affect the flow and collection of water? Of wind? And of the sediments transported by both water and wind? These are fundamental questions in our understanding of planetary bodies and their potential habitability.
This lab introduces what we know about impact cratering, some of the principles we use to simulate a cratered surface (after Howard, 2007), and allows students to explore the effects of stream-power erosion and diffusive erosion on a cratered landscape. Throughout this lab, quantities relevant to Mars are used, but impact cratering is a universal process across our solar system and the models could just as easily be applied to any cratered surface, while the surface processes could be modified to reflect the relevant processes on that planetary body.
Download associated file: ESPIn-2021 Presentation LessonVersion.pptx Mainly visual presentation introducing the importance of considering cratering, and basic concepts related to crater formation.
Learning objectives Skills
Create functions to generate crater topography
Interact with and change input parameters that describe impact cratering
Use LandLab model grids
Use Landlab components to model surface evolution
Visualize surface data and other data in python
Key concepts
The importance of considering impact cratering as a geomorphic agent
Simulating crater distribution and morphology
Basic theory and simulation of landscape diffusion
Basic theory and simulation of river erosion
Effects of diffusion and river erosion on a cratered landscape
Lab notes This lab would work best with an introduction to cratering as a geomorphic process, and the importance of cratering as an age constraint for planetary surfaces. There is enough information that students with limited coding experience could read and run the notebook independently, as there is only one input for an initial number of craters. Students experienced with coding will be able to change parameters and explore the effects. There are several short, open-ended questions scattered throughout that could be used as a problem set or points of discussion.
Requirements This lab requires the Python packages numpy, matplotlib, landlab and random, which must be installed if run locally. On the CSDMS JupyterHub no installation is required.
Acknowledgements This material was enabled and encouraged by the contributors' participation in the Earth Surface Processes Institute (ESPIn) 2021.
References
Howard, A. D. (2007). Simulating the development of Martian highland landscapes through the interaction of impact cratering, fluvial erosion, and variable hydrologic forcing. Geomorphology, 91(3–4), 332–363. https://doi.org/10.1016/j.geomorph.2007.04.017.
