The Virtual Geology of Beloit College (using handheld PCs)
Summary
The goals of this exercise are for students to create their own geologic map and cross-section of the Beloit College campus and to describe the geological history of the campus based on their interpretations. The exercise was initially developed by Cam Davidson (Carleton College) and recently modified to utilize handheld PCs (Trimble GeoXMs).
Because Beloit College sits on glacial sands and gravels that overlie mostly horizontal sedimentary bedrock, a geologic map of campus would be rather simple if students used the actual geology. Therefore, students map the virtual geology of Beloit College. To do so, we create 42 virtual outcrops around the campus. At many of the outcrops, observations and measurements have already been made. However, students need to collect information at the remaining ones (approximately 10 outcrops).
Each outcrop consists of hand samples that represent the rocks exposed at the location and a wooden ramp that represents the attitude of the geologic unit. At each outcrop, students measure strike and dip with a Brunton compass and describe the hand samples. All field data, including GPS coordinates of the outcrop, are recorded in a standardized data dictionary (using GPS Pathfinder Office/TerraSync software) on a handheld PC. A satellite image of the campus is loaded on the handheld PC, so that students can see where they are relative to other outcrops as they collect their data. Data are downloaded in the lab and utilized for construction of the geologic map and cross-section, which are drafted by hand.
Because Beloit College sits on glacial sands and gravels that overlie mostly horizontal sedimentary bedrock, a geologic map of campus would be rather simple if students used the actual geology. Therefore, students map the virtual geology of Beloit College. To do so, we create 42 virtual outcrops around the campus. At many of the outcrops, observations and measurements have already been made. However, students need to collect information at the remaining ones (approximately 10 outcrops).
Each outcrop consists of hand samples that represent the rocks exposed at the location and a wooden ramp that represents the attitude of the geologic unit. At each outcrop, students measure strike and dip with a Brunton compass and describe the hand samples. All field data, including GPS coordinates of the outcrop, are recorded in a standardized data dictionary (using GPS Pathfinder Office/TerraSync software) on a handheld PC. A satellite image of the campus is loaded on the handheld PC, so that students can see where they are relative to other outcrops as they collect their data. Data are downloaded in the lab and utilized for construction of the geologic map and cross-section, which are drafted by hand.
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Learning Goals
Geologic mapping, construction of cross-sections.
As part of this exercise, students:
1) Synthesize three-dimensional (strike, dip) and spatial (x,y) data.
2) Interpret geologic materials, contacts, and structures.
As part of this exercise, students:
1) Learn to operate a handheld PC (Trimble GeoXM).
2) Develop a sense of an acceptable positional error.
3) Describe physical properties of rocks.
4) Work in groups to collect field measurements.
5) Draft and compose a geologic map.
Throughout the experience, the focus remains on the goals of the exercise and not on the handheld PC. The exercise can be completed without the handhelds, but their use streamlines the data collection process. For example, the use of the handheld PCs allows for consistency in field notes. The class discusses what they should collect prior to going into the field. The field form is then pre-loaded into the handheld PC to ensure a complete set of field notes at each outcrop.
Use of the handheld PC also allows students to see their position in the field and on a satellite image of campus. This helps students get a feel for the meaning of scale and an acceptable positional error.
As part of this exercise, students:
1) Synthesize three-dimensional (strike, dip) and spatial (x,y) data.
2) Interpret geologic materials, contacts, and structures.
As part of this exercise, students:
1) Learn to operate a handheld PC (Trimble GeoXM).
2) Develop a sense of an acceptable positional error.
3) Describe physical properties of rocks.
4) Work in groups to collect field measurements.
5) Draft and compose a geologic map.
Throughout the experience, the focus remains on the goals of the exercise and not on the handheld PC. The exercise can be completed without the handhelds, but their use streamlines the data collection process. For example, the use of the handheld PCs allows for consistency in field notes. The class discusses what they should collect prior to going into the field. The field form is then pre-loaded into the handheld PC to ensure a complete set of field notes at each outcrop.
Use of the handheld PC also allows students to see their position in the field and on a satellite image of campus. This helps students get a feel for the meaning of scale and an acceptable positional error.
Context for Use
Integrates mobile technologies into an introductory level course: Environmental Geology and Geologic Hazards
Exercise is used as a stand-alone exercise.
Exercise is used as a stand-alone exercise.
Skills that students should have mastered before beginning this activity:
Prior to beginning the activity, students should be familiar with rocks and minerals, plate tectonics, and geologic structures. They should also have some experience with topographic maps and GPS technology. The activity assumes that the use of a Brunton compass has already been explained to students.Description and Teaching Materials
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Assessment
I evaluate this exercise informally in the field as students are measuring strike and dip and recording field measurements. When data are downloaded, it is also immediately apparent if some field data are missing. This allows students to return to the field and complete their data set. The formal evaluation occurs when I grade the final geologic maps and cross-sections. I focus on how students interpreted their field data when drafting their map, the agreement between their geologic map and cross-section, and how they use the map and cross-section to interpret the geologic history of the region.
References and Resources
Supporting data
High quality satellite images or aerial photos are often available from county or municipal planning departments.Examples of virtual geologic maps and data sets, the GPS Pathfinder Office/TerraSync data dictionary, and a list of typical ramp angles and quantities are available by emailing the author at swansons@beloit.edu.