Virtual Field Trip to the Cagles Mill Outcrop, Indiana
During this virtual field trip students will write sedimentary facies descriptions, draw a stratigraphic column, and develop a set of paleogeographic maps of the Cagles Mill Spillway outcrop. This site is a spillway for a man-made reservoir that exposes the Pennsylvanian Mansfield Formation, including several different facies. This exercise can be used in introductory, historical geology, sedimentology and stratigraphy, and field related classes. Students require web access, where they will use a series of 360 degree and flat photos to characterize composition, texture, sedimentary structures, form, association, and fossils. Using a scaled 3D model of the outcrop, students can measure stratigraphy to create a stratigraphic log.
I have used and moditified this exercise for use with undergraduates in historical geology, sedimentology and stratigraphy, and field camp.
Skills and concepts that students must have mastered
Students should 1) be able describe sedimentary rocks, 2) identify featueres like sedimentary structures, bed form, etc, 3) draw/have seen a stratigraphic log, 4) have some knowledge of fluvial facies and how they move across the landscape.
How the activity is situated in the course
In my Sed/Strat class I take students to this outcrop and use this VFT before the trip to get them comfortable with what we are going to see and allow them to generate hypotheses about the facies, and after the trip to review. In 2020 with the COVID-19 pandemic, I used this in place of my field trip. During field camp I used this site to teach sedimentary unit descriptions and did not do any environmental interpretation.
This activity can be modified to fit the time constraints. We used a lab period plus some time outside of lab to do the activity in Spring 2020. At field camp we used a half of a day to do unit descriptions. When I take students on the actual field trip I use this as a 50 min class activity for them to generate hypotheses about the site before we get there.
Content/concepts goals for this activity
During this assignment students will:
1) Collect their own sedimentary rock description data.
2) Develop a set of facies and environmental intepretations for those facies
3) Draft a stratigraphic log based on their data
4) Draft a set of paleogeographic maps, showing how the land surface changed at different times during the deposition of this outcrop.
Higher order thinking skills goals for this activity
1) Collecting primary data
2) Interpreting from limited data
Other skills goals for this activity
1) Technical writing
2) Drafting (stratigraphic column and paleogeographic maps)
3) Collecting data "in the field"/ field notebook practice
Description and Teaching Materials
Navigate to the virtual field trip by going to and clicking on the picture underneath 'Cagles Mills, Indiana'. This trip is best experienced on a laptop/desktop, but can be done on a tablet or phone,
Students can work individually or in groups to gather data at the field site. There are three major sources of data:
1) Several 360 degree photos. By clicking and dragging their mouse, or tilting their phones, students can view the field site in 360 degrees. By clicking on the 'next panorama' or yellow arrows, they can move to different 360 degree photos.
2) Close-up photos. Each camera icon is a flat, close-up photo of a rock, sedimentary structure, form, etc. Combined with the 360 degree photos students can get a sense of the composition, texture, structures, form, association, and fossils.
3) A 3D model made with Structure from Motion of the outcrop. By clicking on two points you can measure the distance between them. The model is scaled so that each unit is equal to 1 meter (you must tell students this).
Students can be led through this VFT or allowed to explore and generate hypotheses on their own. During the first part of the assignment they should work to gather the primary data they need to write facies descriptions. During the second part of the assignment they should interpret and write up their conclusions.
A document with my interpretations of this site is included in the instructor-only files.
Student Handout (Microsoft Word 2007 (.docx) 9kB Jul11 20)
Strat Column Template (Acrobat (PDF) 793kB Jul11 20)
Paleogeographic Map Template (Acrobat (PDF) 786kB Jul11 20)
Answers (Microsoft Word 2007 (.docx) 607kB Jul11 20)
The website (www.geology.illinois.edu/virtualfieldtrip) will run on a laptop/desktop, tablet, or phone, but I find that the best results occur when students can see the bigger picture on a laptop screen. The activity does require real-time internet access, if this is a problem for your students, contact me and I may be able to provide a (large) file. Some of the photographs are fairly high resolution, and take a few seconds to load on slower connections.
Teaching Notes and Tips
If the photos are loading slowly, students need to be patient. If they click too many times the photo will close (1 click to open, 1 click to close).
The website that hosts the digital 3D model says that they lengths are unitless; however, this model has been scaled so that 1 unit is 1 meter.
Currently, my website has a handout on it that is used for the physical field trip. Please start with the student handout uploaded here if you intend to do a fully virtual trip.
I use the report as the assessment, looking for good observations from the photos and reasonable interpretations and paleogeographic maps.
References and Resources
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