A Traverse Through Time and Space: A Paleoenvironmental Analysis of Devonian Strata in New York State
This is a field-based mini-project that requires students to synthesize their field data to 1) determine the depositional environments both across New York State (from the Catskills, NY to Rochester, NY) during the Lower and Middle Devonian, 2) recognize major unconformities, and 3) decipher the relationship between tectonics and sedimentation.
Skills and concepts that students must have mastered
How the activity is situated in the course
Content/concepts goals for this activity
- measure stratigraphic section
- identify sedimentary rocks
- identify sedimentary structures and know how to measure paleocurrent direction and plot these data on rose diagrams or stereonets
- identify fossils and their taphonomy to determine the possible environmental of deposition (water depth, salinity, wave action)
- draw stratigraphic columns by hand that includes all of the above information
- plot paleocurrent data on rose diagrams or stereonets (first, by hand and later using a computer program) and
- draw neat stratigraphic columns by hand that includes all of the above information.
For this project, we visit five local outcrops and take one 3-day trip to the Catksills, NY region. Students have 8 stratigraphic columns to use for their paleoenvironmental analysis of Lower and Middle Devonian strata across New York State.
Higher order thinking skills goals for this activity
- determine lithofacies associations
- make process interpretations of sedimentary textures and structures, linking products to processes that we saw in the field or simulated in the lab during the first month of the course
- determine environment(s) of deposition of each formation
- correlate the stratigraphic sections across New York, especially the Hamilton Group, based on lithostratigraphy and then biostratigraphy
- create fence diagrams
- draw generalized facies maps for different time slices of the Lower and Middle Devonian across New York (with scant data)
- create generalized, annotated cross-sections that depict the basin highlands and lowland locations and sediment transport direction
- write a short paper that describes the geologic history of New York during the Lower and Middle Devonian that focuses on environments of deposition, periods of erosion and quiescence, and tectonism by synthesizing all of the above data
Other skills goals for this activity
- work in groups of 2-3 students (teamwork)
- develop keen observation skills
- keep an accurate, legible, organized field notebook that separates observations from interpretations
- Excel and other computer programs
- use Brunton and Jacob staff to measure stratigraphic section
- use Brunton to measure paleocurrent directions
- plot stereonets and rose diagrams
Description of the activity/assignment
Determining whether students have met the goals
- I collect field notebooks and make comments and suggestions on how to improve their work using large Post-It notes rather than writing in their notebook. Because I expect students to read these comments and use them to do a better job during the next field exercise, I collect their notebooks at the end of lab, and return them by the beginning of the next class meeting. Their graded work depends on the quality of their field notes. To grade the notebook and the work penalizes students twice.
- I grade the hand-drawn stratigraphic sections as this is the basis of all other analyses. These are submitted each week.
- I also grade any paleocurrent plots generated each week.
- Each week, I pose a few questions before we go into the field to focus our work that day. I grade their responses each week.
- As part of the culminating assignment, students submit facies maps and correlated stratigraphic columns for a grade and identify any stratigraphic pinchouts and unconformities that occur across the state as well as coarsening or fining upwards sequences.
- The culminating exercise is to write a geologic history (~6 typed pages, single-spaced, not including figures) of New York during the Lower and Middle Devonian using all the data and figures already submitted and returned. All of their previously work (stratigraphic columns, stereonets, etc.) are re-submitted with the paper. I expect any errors in the figures, maps, and sections to be corrected in this final version.
Teaching materials and tips
- Boggs, S. Jr. 2006. Principles of Sedimentology and Stratigraphy, 4th edition, Prentice Hall, 662 p.
- Brett, C.E. and Ver Straeten, C.A. 1994. Stratigraphy and facies relationships of the Eifelian Onondaga Limestone (Middle Devonian) in western and western-central New York State. New York State Geological Association 66th Annual Meeting Field Trip Guidebook, p. 221-270.
- Compton, R.R. 1985. Geology in the Field. Wiley. 416 p.
- Fichter, L.S. and Poche, D.J. 2001. Ancient Environments and the Interpretation of Geologic History. Prentice Hall: Upper Saddle River, NJ. 310 p.
- Johnson, K.G. 1987. Strand-line facies of the Catskill Delta Complex (Middle and Upper Devonian) in eastern New York State: in Centennial Field Guide Volume 5, Roy, D.C. (ed.) Northeastern Section of the Geological Society of America, p. 129-132.
- Marshak, S. and Englender, T. 1987. Exposures of the Hudson Valley Fold-Thrust Belt, west of Catskill, NY: in Centennial Field Guide Volume 5, Roy, D.C. (ed.) Northeastern Section of the Geological Society of America, p. 123-128.
- Patchen, D.G., Avary, K.L., and Erwin, R.B. 1985. Correlation of Stratigraphic Units of North America (COSUNA) Project, Northern Appalachian Region: American Association of Petroleum Geologists. Chart. 1 sheet.
- Stow, D.A.V. 2005, Sedimentary Rocks in the Field: A Color Guide. Academic Press. 320 p.
- Tucker, M. 2003. Sedimentary Rocks in the Field. Wiley. 244 p.
- Woodrow, D.L. and Isley, A.M. 1983. Facies, topography, and sedimentary processes in the Catskill sea (Devonian), New York and Pennsylvania: Bulletin of the Geological Society of America. vol. 94. p. 459-470.
- Woodrow, D.L. 1983. Topography and sedimentary processes in an epicontinental sea: In, Stanley, D.J. and Moore, G.T. (eds.) The Shelfbreak: Critical Interface of Continental Margins, Society of Economic Paleontologists and Mineralogists, Special Publication. no. 33. p. 159-166.