Computational Geoscience Center Hosts Cross Section Construction and Restoration Workshops

The Cross Section Construction and Restoration Workshop taught by researcher Amanda Hughes and adjunct professor Steven Lingrey began with three three-hour sessions in November focused on shortening/contractional settings (i.e., fold-and-thrust belts), with three more three-hour sessions on extensional settings (rift margins) scheduled for February and March, as these different geologic settings require different methodological approaches.  

Hughes and Lingrey intend for the workshops to strike a balance between describing the fundamental principles that guide how one builds and restores geologic cross sections, and practical instructions on how to construct and restore the cross sections using the software programs Lithotect and Move.

Here, Hughes describes the workshops:

On the first day, we focused on the concepts and approaches that help you construct the cross section in thin-skinned shortening environments. We showed students how to collect all of the geologic surface and subsurface data that they have and post them to a cross-section, then use specific modeling approaches to fill in the gaps in a geologically-sound way.  

We provided them with advice on specific features to look for in the geology to help decide between different modeling approaches, then showed them how to construct the different models in the software programs by using example structures from Nigeria, Taiwan, and Canada.  

On the second day, we focused the discussion on methods for constructing cross-sections in basement-involved systems, again with an exercise demonstrating this approach on a geologic structure in Wyoming. 

In the third session, we discussed the principles that guide cross-section restoration, then applied these concepts by going through the exercise of restoring a cross section with the students using Lithotect and Move. We chose a published cross section selected by one of the students of shortening in the Andes, in order to show students how we are able to validate and interrogate the structural interpretation that the authors had made.  

So far, mostly graduate students have attended, but undergraduates are welcome to join the upcoming sessions as well, which will focus on the concepts and methods that must be used in rift and extensional settings. 

The concepts and skills that Steve and I cover in this course are helpful tools for students studying structural geology and tectonics, reflection seismology, and basin analysis.  

Having an understanding of these methods and concepts will help students construct and restore their own cross sections for their research, and evaluate cross sections that they see in the published literature. This allows them to model the subsurface geometry, and the amount and timing of shortening or extension in their geologic study area, which is important for studies of regional tectonics, petroleum systems, and seismic hazard assessment.