Effective Ways to Teach Topics in Sedimentary Geology
These sessions explored different ways to teach key areas in sedimentary geology. Each presentation has a downloadable classroom activity associated with it. See all classroom activities for teaching sedimentary geology.E1 SEQUENCE STRATIGRAPHY
Simplified carbonate sequences stratigraphy (Maya Elrick, University of New Mexico)
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Sequence stratigraphy is jargon-laden and typically presented in an overly complicated manner which turns many students off. This lab is a simple and straightforward introduction to sequence stratigraphic interpretations of a carbonate platform using a combination of facies analysis, facies correlations, hand samples, thin sections, and is followed up by students reconstructing the platform profile at specific time intervals during sequence development to detect and interpret changes in platform morphology.
Hands-On Sequence Stratigraphy (Dennis Hubbard, Oberlin College)
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One of the difficult concepts for students to understand is how stacked parasequences form and what they tell us about the interaction between relative sea-level change and sediment supply. A dated but easily manipulated (and free) modeling program (Fuzzim) allows the creation of increasingly complex depositional scenarios. A single parasequence generated over one sea-level cycle demonstrates the relationship between the rate of sea-level rise and transgression/regression. By superimposing shorter sub-cycles, the model builds aggrading, prograding and retreating depositional packages. The sea-level curve, initial topography (e.g., ramps vs. more abrupt shelf margins), and sediment supply can be easily modified by the instructor or the student. Students work through basic model set-up and complete several model runs. They are encouraged to modify input conditions and explore the effects on sedimentary output. The goal is to develop an intuitive understanding of how large-scale sedimentary cycles relate to the interplay between sea level and sediment supply. In the course at Oberlin College, model output is used in conjunction with a Walther's Law exercise (will be available) and a week-end field trip where the sedimentary cycles generated by the model can be observed in outcrop. This approach integrates the use of hand samples, thin sections, and outcrop observation to provide a hands-on connection to the more abstract concepts developed by the models.
Using data from the Experimental Earthscape Facility (Jurassic tank) to visualize basin-scale stratigraphic architecture (Tom Hickson, University of St. Thomas)
See a classroom activity on this topic: PowerPoint presentation (PowerPoint 2.6MB Aug12 06)
Walther's law and sequence stratigraphic concepts can be difficult to visualize when using real-world examples from the modern and ancient. As a bridge toward this end, I use digital imagery from an experimental subsiding sedimentary basin (the Experimental Earthscape Facility, a.k.a. "Jurassic tank" at the St. Anthony Falls Lab) in a 3-week long project to help students forge a connection between basin-wide forcings and the resultant stratigraphic architecture. Students are asked to predict which of three variables (base level, sediment supply, or subsidence rate) were altered to produce a given experimental stratigraphic architecture. They must link their interpretation to actual depositional environments and they must predict what stratigraphic sections will look like at different places in the stratigraphy. This exercise has been extremely helpful in helping students understand how basin-scale stratigraphic architecture is generated.
E2 TRANSPORT DYNAMICS
Use of an inquiry approach for exploring relationships between small stream dynamics, channel geometry, and bedform movement (Kerry Keen, University of Wisconsin-River Falls)
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For several years, I have been using an open-ended inquiry project in my sedimentary geology course to explore relationships between the nature of stream flow, stream dynamics, geometries of the channel, and characteristics and rates of movement of bedforms. The small-group inquiry project begins with students observing a section of the stream (located a couple miles from campus), followed by brainstorming questions about the features observed in the stream and on its bed, then to designing and implementing experiments to answer specific questions that they have formulated, and concluding with data analysis and student presentations of their research. Approximately a dozen steps comprise the complete inquiry approach, and I will discuss aspects of implementing this method, along with its pros and cons.
Using a Flume to Demonstrate Fluid Properties and Sediment Transport (Jill Singer, SUNY-Buffalo State College)
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A recirculating flume offers ideal opportunities for conducting demonstrations designed to help students observe and understand a variety of fluid properties and the basics of sediment entrainment and transport. This session will outline uses of laboratory flumes, provide sample exercises, and offer suggestions for designing and constructing a flume or wave tank.
Experiments with density-modified flow (Jim Trexler, University of Nevada, Reno)
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A very important process in sediment transport is the flow of fluids above, within, or below lakes or the oceans. Gravity, slope, and the contrast in densities determine the behavior of these density-modified flows. Density differences can be caused by temperature, salinity, and/or sediment suspended in the water. This experiment is designed to allow students to observe the details of how density differences affect the behavior of fluids flowing within other fluids. Students vary slope angle and fluid density, and develop a model for predicting flow behavior. Fluid density is modified using epsom salt (MgSO4). An acrylic tank with an adjustable ramp allows students to time the flow over a measured distance, and observe flow behavior in detail. fluorescein dye is used to make the flow dramatically visible.
Understanding and Applying the Exner Equation (Chris Paola, University of Minnesota, NCED)
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The Exner equation describes the mass balance for sediment deposition and erosion. The original version embodies the main short-term processes by which the stratigraphic record is created, and it can easily be modified to include additional processes like subsidence, compaction, and carbonate or evaporite formation. The Exner equation lends itself readily to visualization and physical examples; it is far more important in quantitative sedimentary geology than the usual topics from fluid mechanics that are included in undergraduate sedimentary geology texts. We will look 'under the hood' of the Exner equation and discuss what its terms mean and how to present it to undergraduates with emphasis on building intuition rather than mathematical solution methods.
E3 PETROLOGY AND DIAGENESIS
Cementation and Neomorphism: Incorporating the Basics of Diagenesis into Any Sedimentary Geology Course (Kathy Benison, Central Michigan University)
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Diagenesis is an important sedimentary process and undergraduate students greatly benefit from learning how to recognize and interpret common diagenetic features. This can be accomplished with a two to three week unit that includes lectures and lab activities that focus on cementation and neomorphism, but also includes dissolution, compaction, and paragenetic sequence.
The Tutorial Petrographic Image Atlas for Sandstones (Kitty Milliken, University of Texas at Austin)
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This interactive digital resource was created with the goal of preserving petrographic knowledge and experiences in a curriculum that is increasingly squeezed by the competing demands created by the increased subject-matter load that must be conveyed to undergraduates in the space of a 4-year program. The tutorial contains mapped, "live", petrographic images (around 650) with in-depth content related to identification of sandstone components. Most of the content is hidden until the student calls it up through active searching, thus conveying something of the sense of exploration that is fundamental to petrography. Today's computer-savvy students adapt readily to learning from digital resources of this type. The content of the tutorial helps to offset some of the expense (collections, equipment, time, expertise) intrinsic to petrography instruction.
Red rock and concretion models from Earth to Mars: Teaching about diagenesis (Marjorie Chan, University of Utah)
See a classroom activity on this topic : PowerPoint presentation (PowerPoint 10MB Aug2 07)
The knowledge of sedimentary features and processes (e.g., deposition, diagenesis, and weathering) can be used to help enhance our knowledge of extraterrestrial geology. Terrestrial analog examples of red rock coloration and iron-oxide concretions can help students understand water processes in the Burns formation at Meridiani Planum of the red planet Mars. Study of terrestrial concretions in undergraduate sedimentology/stratigraphy courses an excitement and increases student interest in wanting to understand the Mars "blueberries". Students can look at comparisons of size, structure, texture, mineral composition, and more. It is important to understand both pros and cons of analogs. The comparisons show students what parameters are important to look at and how to utilize multiple working hypotheses and models. Students also grapple with the idea of whether there might be potential bacterial life forms on Mars and how life could be preserved in rock. This opens up discussion on the influence of biological/organic components in enhancing geologic processes and precipitation.