Quantitative Skills > Teaching Resources > Activities > Here we see it, but what's beneath? Effective geologic cross-section problem solving

Here we see it, but what's beneath? Effective geologic cross-section problem solving

Rob Benson, Adams State College, based on experiences delivering lab exercises from an in-house lab manual by Rob Benson and D. C. Stewart, feedback from SERC QL workshop colleagues, and excellent class website materials developed by Jimm Myers (www.gg.uwyo.edu)
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This is a partially developed activity description. It is included in the collection because it contains ideas useful for teaching even though it is incomplete.

This activity has benefited from a review and suggestion process as a part of an activity development workshop.

This activity has benefited from input from faculty educators beyond the author through a review and suggestion process as a part of an activity development workshop. Workshop participants were provided with a set of criteria against which they evaluated each others' activities. After the review, the authors developed a plan for revising their activities based on the feedback they received from their peers. To learn more about this review process, see http://serc.carleton.edu/quantskills/review_processes.html#2006.

This page first made public: Jul 20, 2006


This activity will challenge students to synthesize surface observations (strike and dip and other planar data, contacts, etc.) from a map to determine the location of a variety of important subsurface features using geologic cross-sections. Students will complete the following tasks:

  1. topographic profiles as needed,
  2. spatial location of surface data,
  3. assessment of variables,
  4. assessment of data quality,
  5. cross-sections as needed to effectively identify the nature of the assigned subsurface feature, and
  6. a standard scientific report describing the nature and conclusions of the project.

Learning Goals

1. developing spatial analytic skills
2. applying problem-solving to geologic principles, superposition, cross-cutting, etc.
3. an introduction to scientific method and writing

Data analysis, critical thinking, collaborative discussion and model development will all be infused in a various ways. Writing, and possibly oral and GIS skills will be developed by this activity.

Context for Use

The activity is for an introductory level class of 10-30 students at a state-assisted 4 year undergraduate college. Lab sections are typically 12 or less. The setting of the activity will be a multiple session lab project for groups of students, perhaps over three labs. Some field activity may be used to provide students with a context of the data. No special equipment is required. Only basic college entrance proficiency will be assumed. The activity will occur toward the end of the semester, in a semi-capstone role. This activity will be very easy to adapt to other and higher level classes and settings.

Description and Teaching Materials

under development

First part: Materials for the first part of the lab will include local synthetic geologic maps representing the local geologic setting. Some additional material should be used as needed for demonstrations of map information. This material could be used for illustrating folds, faults, etc. Since this activity is designed for the later part of a general introductory geology course, students should have a basic idea of geologic structures, and should have seen examples in class. An early field trip might be a useful resource to prep students for this lab. Perpindicular cross-section lines should be assigned for this part, and will be located such that the completed cross-sections will not be complex. The cross sections will effectively illustrate the effects of strike and dip on a projection.

Students will work in groups. Experience suggests that 2 to 4 students per group is workable, with 3 being optimal. For the first part of the activity the groups should produce the cross-sections, which includes topographic profiles as needed, spatial location of surface data, and generation of the actual cross-sections. Each group will have determined what the group's subsurface "question" is at the end of the first lab. The questions should be from a list provided in the activity. Each group will then have time to research and learn about what the geologic controls are for the subsurface "question" or feature before the next lab

Subsurface question options available to students at this time will be from the following list:

  1. Where might we find a suitable aquifer for a new residential subdivision?
  2. Where might we find faults that might cause damage from displacement during an earthquake (and not build there)?
  3. Where might we find a possible gold deposit that will pay off our college loans?
  4. Where might we look for and possibly develop geothermal resource for a spa resort, geothermal power, or onion drying plant?

Each subsurface question package will have additional information relevant to the question. The package will include additional "hints" and resources to effectively guide further inquiry by the group. This inquiry will prepare each group for further discussion in the second part.

Using the aquifer example, additional information relevant ot the question might be descriptions of producing aquifers in the area, etc. Ideas on how to to explore for water resources might be included here as well.

Second part: By the beginning of the second part, each groups should have a workable set of cross-sections. The can be critiqued at the group level, by the instructor. Each group should then be able to request additional materials as needed, e.g. drill hole logs, geochem data, etc. as they determine their additional needs to solve the assigned problem. Groups will be completing assessment of variables and assessment of data quality in this section. The third part will include a followup standard scientific report in both written and oral format, describing the nature and conclusions of the groups activity. Groups will present their finding to the class for discussion and feedback.

Matrix of quantitative skills learned in this activity

Basic X
intermediate X X X
intermediate X X X

Teaching Notes and Tips

under development

Since this is an introductory class, it will be important to consider how ready students are for the idea of apparent dip on a cross-section. Furthermore, students must be encouraged to be thinking about the idea of earth resources such as water, mineral deposits, hydrocarbons, etc., or geologic hazards that might be discovered as a result of cross-section interpretation.

This activity is an example, using Rio Grande Rift geology only because Adams State College is located in the Rift. The ideas in this activity here could easily be migrated over to any other geology relevant to a campus. Student will have some identity with local geology although they might need to be forced to acknowledge it. The importance and application of geological inquiry will become clear to the students. An understanding of natural resources and hazards.

Expect that groups will need significant feedback during the second section.

28 JUN 06 note:

Materials that will be uploaded over the next couple of months are:

1. The geologic map with cross-section locations

2. The subsurface question option sets, with data for the first part of the activity and the second activity.


under development

References and Resources

under development

Google Earth could be used as a visualization tool to assist students in understanding 3D spatial context more. Additional geologic map/cross-section pairs might be used to provide some end-product concepts, in other words, what the results should look like.