Upper-level undergraduate majors and graduate students.

Students should have familiarity with basic sequence-stratigraphic methods and terminology, including:

• stratal terminations (onlap, downlap, toplap, offlap, erosional truncation)
• stratal stacking patterns (progradational, aggradational, retrogradational)
• sequence-stratigraphic surfaces (sequence boundary, transgressive surface, maximum flooding surface)
• systems tracts (lowstand, transgressive, highstand, +/- falling stage, depending on your preference)

This is a large mid-term project worth 25% of their overall grade. By this time in class we've done small exercises introducing basic sequence-stratigraphic terms and giving student some practice with the concepts.

This project provides students an opportunity to independently implement sequence stratigraphic approaches and encourages them to consider the influence of basin-subsidence geometry on stratigraphic patterns. This activity also supports the overarching coarse goal: for students to learn to formulate stratigraphic hypotheses, determine the appropriate methods of data collection, analyze and communicate the results, and evaluate uncertainty.

Students are asked to formulate hypotheses about how basin subsidence influences sedimentary patterns, compare new experimental data to a previously published dataset, and evaluate uncertainties associated with sequence-stratigraphic methods.

This project supports technical-writing and data-analysis skills. In particular, students use Illustrator (or Inkscape) and ImageJ software to extract quantitative data from experimental images.

In 2002 an experiment - XES 02 - was conducted at the St. Anthony Falls Lab. XES 02 was designed to explore how eustatic sea-level cycles of different rates and magnitudes control straigraphy. In 2009, Martin et al. published an extensive analysis of how sequence-stratigraphic surfaces reflect paleo-topographic surfaces and the degree to which sequence-stratigraphic packages record center-of-mass migrations driven by changes in the balance of sediment supply and accommodation creation.

In 2010, XES 10 was conducted as a sister experiment to XES 02 and was designed to explore how basin subsidence geometry influences stratigraphic patterns. Experimental boundary conditions XES 10 were matched closely to those in XES 02 except subsidence geometry was reversed; XES-02 subsidence rates increased away from the source (i.e. "fore-tilted" subsidence, broadly similar to what is observed on passive margins) whereas XES-10 subsidence rates were highest close to the source (i.e. "back-tilted" subsidence, broadly similar to patterns in foreland basins).

In this assignment, students are tasked with comparing XES-10 stratigraphy to the XES-02 results presented in Martin et al. in an effort to evaluate how basin subsidence geometry influences stratigraphic patterns and sediment mass balance.

Students are provided a high-resolution dip-section image of XES-10 stratigraphy and map the deposit using Adobe Illustrator (or Inkscape), identifying key surfaces and bounded stratal packages. Using ImageJ, students then calculate the center-of-mass for each stratal package and compare their results to those of Martin et al.
Assignment handout (Acrobat (PDF) 689kB Jun6 14)

Centroid mapping instructions (Acrobat (PDF) 387kB Jun6 14)
Martin et al., 2009 paper (Acrobat (PDF) 12.7MB Jun6 14)
Adobe Illustrator tutorial (Microsoft Word 2007 (.docx) 303kB Jun6 14)

This project is not intended to be a "test" of the student's ability to identify specific stratigraphic features as much as it is an opportunity for them to explore and consider the power and limitations of sequence stratigraphy.

This project demands a lot of time from the students (the students worked over the course of a month that included spring break), but in the end, students with no sequence-stratigraphic background before the course felt very comfortable using these methods and thinking critically about stratigraphic patterns.

For a project based on XES 02, see: http://serc.carleton.edu/NAGTWorkshops/sedimentary/models/xes_basin_project.html

Students should include all the information detailed in the project instructions and articulate thoughtful points in the discussion.

A forthcoming paper in JSR on XES 10 can be used as a reference for more information about the details of that experiment.

E. Hajek, P. Heller, A. Petter, A. AlAbbad, W. Kim, In Press, Amplification of shoreline response to sea-level change by back-tilted subsidence, Journal of Sedimentary Research.

Overhead video of XES 10 available here: https://www.youtube.com/watch?v=WWi39PWrHeY

ImageJ software freely available here: https://imagej.nih.gov/ij/

Inkscape software freely available here: http://www.inkscape.org/en/