Building a Facies Model
The purpose of this exercise is to help students understand a model by "building" it "piece by piece" and relating the various components to concepts they learned earlier in the semester, such as energy relationships, base level, facies, facies associations, and Walther's Law. It is designed to begin as an in-class discussion led by the instructor using a black or white board, followed by group collaboration, out-of-class exercises, and concluding with a formal examination.
The example provided here is for a prograding shoreface system; however, the same approach can be applied to any depositional system.
Skills and concepts that students must have mastered
How the activity is situated in the course
Content/concepts goals for this activity
Higher order thinking skills goals for this activity
Other skills goals for this activity
Students form groups of three to four to compare their work and make modifications to their individual models.
Students compare their models to published versions and to try to understand and explain differences. Part of this is to emphasize that there is a range of correct interpretations and to not become locked into thinking there is a single solution.The assignment requires a written report at the end of each facies model, demonstrating how they would explain the model to another geologist.
Description and Teaching Materials
Step 1: Each facies model is introduced through an in-class discussion, during which the instructor guides students toward an understanding of basic concepts, such as energy regimes and the nature of boundaries (surfaces) between these regimes, as well as likely sediment characteristics, structures, and transport processes and directions. These items are outlined on a black- or white board as they are discussed. Though the shoreface system is used as an example in this document, a similar approach can be applied to any depositional system.
Step 2: Students work in groups of three or four to draft a reasonable facies model consisting of a plan view and both depositional strike and dip cross-sectional views. Though they compare and contrast their models in groups, each student is, ultimately, responsible for his/her own final model.
Step 3: Students compare and contrast their models to those from published sources to try to understand differences between interpretations. Part of this is to emphasize that there is a range of correct interpretations and to not become locked into thinking there is a single "correct" solution.
Step 4: Students prepare a final draft of their model, along with a written outline of how they would present/explain the model to others. This is submitted for a grade.
Step 5: Three models (two clastic and one carbonate) are chosen from the nine discussed in class for inclusion on an exam. Students reproduce their models and, in narrative form, flesh out their outlines. To avoid rushing them on the exam, I make it available over a three day time frame and allow them to come to my office when ready.
Teaching Notes and Tips
Instructor's Notes (Acrobat (PDF) 1.4MB May30 14)
References and Resources
There are many references for facies models. Some of those I make available include:
Facies Models by Walker & James
Depositional Sedimentary Environments by Reineck & Singh
Sandstone Depositional Environmnents - AAPG Mem. 31
Carbonate Depositional Environments - AAPG Mem 33