A Project for Students Using Data from the XES Basin

A project on sedimentary basin architecture and sequence stratigraphy

Synthethic stratigraphy created in an XES Basin experimental run (XES 02)

Imagine that you asked your students to interpret a seismic section using sequence stratigraphic principals and concepts. The ultimate scientific goal, of course, is to interpret the stratigraphic architecture and to develop an internally consistent interpretation of how this stratal geometry was formed. Now imagine that your seismic line has extremely high resolution. Finally, imagine that you know the 'right answer' to the interpretation, that you know the genesis of this stratigraphy precisely. XES Basin data can fulfill this scenario and can play a critical role in connecting earth surface processes to the formation of sedimentary basin architecture. The following project is designed to forge a strong link between geomorphic processes, tectonics, sedimentation, and stratigraphic architecture. Students interpret the synthetic stratigraphy in the image above and present their interpretation as a GSA-style poster.

Project goals

By the end of this project, students should be able to:
  • explain how Jurassic Tank works, why it was built, and how it can be used to link the real world (outcrops and subsurface, well data) with sequence stratigraphic models of basin-scale sedimentation.
  • interpret a cross sectional image from Jurassic Tank (which is very similar to a 2D seismic line), in terms of changes in base level, subsidence, or sediment supply.
  • link specific, real-world depositional environments to parts of an XES Basin image and understand how they respond to changes in base level, subsidence, or sediment supply (i.e. Walther's law).
  • apply sequence stratigraphic concepts and terminology to a synthetic stratigraphic cross section diagram generated in the XES Basin.
  • create a professional poster in Adobe Illustrator or similar graphics software.

Project outline

The project includes the following steps:
  • [Optional, but very helpful] Students complete the desktop delta assignment.
  • They then read the GSA Today article on Experimental Stratigraphy that outlines how Jurassic Tank works.
  • Students are given the project guidelines handout and a link to digital images of a dip section through a Jurassic Tank deposit (the image at the top of this page). Every student gets the same image.
  • They are asked to accomplish four things, summarized in the form of an Adobe Illustrator poster that meets GSA poster guideline standards:
  1. Interpret the section using appropriate sequence stratigraphic concepts, focusing in particular on sequence boundaries and maximum flooding surfaces. They must use Adobe Illustrator to place actual interpreted lines on the cross section image and they must annotate these lines with the proper sequence stratigraphic terminology.
  2. Infer real-world depositional settings that might logically be appended to different parts of the deposit image (fluvial, shoreface, topset, foreset, bottomset, etc.) and then outline the portions of the cross section that correspond to these depositional settings.
  3. Create three stratigraphic sections, spaced at roughly equal intervals from upstream to downstream on the section, that embody the appropriate components of facies models that correspond to the depositional settings that they choose. They need to pay attention to lithologies, grain sizes, sedimentary structures, and any other features that would be associated with each of the environments they have outlined.
  • Finally, they must take a stab at what was actually done to create the deposit, based on their careful analysis and interpretation.

Project context

This is the last of three, four- to five-week long projects in my project-based sedimentology and stratigraphy course. By the time students begin this project they will have experience with:
  • Basic concepts of sediment transport
  • Describing sedimentary rocks in hand sample, thin section, and outcrop.
  • Recognizing and interpreting primary sedimentary structures, mainly in siliciclastic rocks
  • Correlating measured sections
  • Sedimentary facies and depositional environments
  • Interpreting depositional processes and sedimentary environments from outcrops and measured sections
I allow about four weeks for students to complete this project. All class and lab time (6 hours of in-class time per week) are essentially devoted to completing it. I present mini-lectures on an as-needed basis as students work (struggle?) in a 'workshop' format to complete the poster. Some of the topics of these mini-lectures include: Walther's Law; parasequences and parasequence stacking patterns; deltaic depositional systems; and lowstand, highstand, and transgressive systems tracts. I try to make these short (20-minutes or less) and directly applied to the project. It is my intention that students discover the material behind this poster project as they go, so I also direct them to the book (I have been using Boggs, but I have many others laying around the classroom while this project is going on) and other readings. We use the web as a resource and anything else that helps them to understand what is going on and how to make their interpretation. I am very careful to emphasize two things:
  1. There are NO wrong answers, just poorly-supported interpretations. I am not looking for the right answer. I am looking for a well thought-out interpretation that makes use of all of the observations.
  2. I will not answer most science-based questions unless the student has demonstrated that they have made some effort to answer the question on their own (i.e. they have gone to the book). The socratic method is very much in play here.

Project documents and files

Basin-scale stratigraphy and stratigraphic architecture: using Jurassic Tank to understand large-scale stratigraphic controls: (Acrobat (PDF) 1.6MB Jun26 08) Project write-up and hand out for students describing the goals and structure of the project.

Images of the deposit: low, medium, and high resolution images of the same slice through the XES Basin deposit used in this project (Zip Archive 54.7MB Jun27 08) (caution large file!)


Geomorphology of the sediment transport surface

This video also shows the topographic evolution of the sediment transport surface over the duration of the run (based on laser topographic scans of the surface).
Higher resolution QuickTime version for downloading and saving (Quicktime Video 5.9MB Jun26 08)

Fly-through of the deposit in dip section

This video was created by compositing high resolution serial dip section images into a movie sequence. It is as if you are 'flying through' the deposit from one side to the other. Resolution changes in this video because half of the deposit was cut in dip orientation and the other half in a strike orientation.
Higher resolution QuickTime version for downloading and saving (Quicktime Video 10MB Jun26 08)

Fly-through of the deposit in strike section

This video was created by compositing high resolution serial strike section images into a movie sequence. It is as if you are 'flying through' the deposit from upstream to downstream. Resolution changes in this video because half of the deposit was cut in dip orientation and the other half in a strike orientation.
Higher resolution QuickTime version for downloading and saving (Quicktime Video 36.5MB Jun26 08)

The "answer"

Base level curve for this experiment Click on the thumbnail image to see the base level curve that was used to generate the synthetic stratigraphy for this project.

Data (Excel 646kB Jun27 08) used to plot the curve in the image above and a brief description of the base level changes used to generate the synthetic stratigraphy

Three examples of student posters (Zip Archive 2.6MB Jun27 08) from this project. They serve as good keys to the project because they represent some of the better examples of how students (in my course, at least) have completed this project.