Aurora Mastodont Project - Matrix Analyses Project

David Voorhees, Waubonsee Community College
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This is a laboratory based assignment that is for Introductory level geoscience classes (Physical Geology, Historical Geology, Earth Science) that brings an authentic research experience to your students. In the assignment, students are asked to process and interpret screenwash from the 2004 Aurora Mastodont Project, and to contribute authentic research results to the ongoing post-dig analyses. Students then contribute their results to a database to compare theirs to their colleagues around the country. This is an ongoing and free exercise available by requesting samples of screenwash (details below). This is one of several exercises that I ask my Earth Science students to complete as an introduction to the nature of science and the geosciences, that I call GSI (GeoScience Investigations) which was presented as a poster during the 2013 GSA in Denver.

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I have used this as a lab assignment for undergraduate courses in Physical Geology, Historical Geology and Earth Science that are almost all non-majors. It has also been used in other Geology labs and countless Middle and High School classes around the country. The lab can be done with 4 students processing a 50 ml vial of screenwash in about 2 hours. The lab can be adjusted to include less or more analyses, as time permits.

Skills and concepts that students must have mastered

The students need to have a basic understanding of glaciers (especially kettles), glacial sediments (peat, marl, gyttja, till), post-glacial ecosystems, mastodonts, stratigraphy and what is screenwash. These are all discussed in the powerpoint and in the lab write up that are provided below.

How the activity is situated in the course

I use this as a stand-alone lab exercise, after supporting material has been presented in lecture (i.e. glaciers and geologic time).


Content/concepts goals for this activity

Students are asked to test whether an artistic reconstruction of the mastodonts in Northern IL (specifically Aurora) about 11,000 years ago is scientifically accurate using the results of their screenwash analyses. This image is provided on the first page of the lab handout.

Higher order thinking skills goals for this activity

At the beginning of the lab, students are asked to predict expected results prior to obtaining data. The screenwash is separated into several components (gastropods, plant material, rocks, historic debris, and unusual or interesting), and interpret their results, as well as their colleagues in the lab working at different stratigraphic levels. From the class results, an overall model and conclusions are developed.

Other skills goals for this activity

Extensive group work, mathematical analyses (per cent variations with depth and time), fossil identification (gastropods), stratigraphic interpretation. ecologic analyses (using gastropod species and plant species keys provided)

Description and Teaching Materials

Students view an introductory presentation by the instructor (provided below), answer preliminary questions in the lab handout, then process 50 ml of screen wash. Students interpret all samples processed by the class to develop class model (i.e. jigsaw). Equipment needed are screenwash (free), paper to spread screenwash on, tweezers, hand lens, scale, calculator, magnets, identification charts (provided below). More information can be found at
Screenwash samples (free) can be requested from or
Data is submitted to
Here is a poster from GSA 2011 about AMP-MAP GSA AMPMAP
GSA AMPMAP (Acrobat (PDF) 1MB Jun1 14)
AMP-MAP lab (Microsoft Word 2007 (.docx) 2.3MB Aug12 14)
Gastropod identification chart (Acrobat (PDF) 3.6MB Aug12 14)
Plant identification chart (Acrobat (PDF) 107kB Aug12 14)
AMP-MAP Introduction (PowerPoint 2007 (.pptx) 15MB Aug12 14)

Teaching Notes and Tips

Common confusion is at
1) plotting data and realizing the stratigraphic meaning to the depths
2) recognizing that their data is from a kettle, and not from the actual landscape the mastodonts lived in. In other words, the kettle is where the mastodonts died and not where they lived


An acceptable grade on the lab, using 2 to 5 points per question.

References and Resources

Complete description on how to bring authentic research using Mastodonts into your classroom.
Screenwash samples can be requested from or
Data is submitted to