Google Earth Exercises for Structural Geology
Jonathan Dyess and Vicki Hansen ,
University of Minnesota Duluth Author Profile
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Students use imagery taken from Google Earth to create photo-geologic maps of areas with various structural styles. Concepts include basic geologic mapping principles, remote data set interpretation, structure-topography interaction, visualizing structures in 3D, temporal relations, and rheology. Students learn that geologic maps vary from person to person and that a geologic map is an interpretation. Students gain significant geologic mapping experience using relatively little class time.
We use these Google Earth Exercises (GEE) in our undergraduate structural geology course. These exercises can be easily adapted to accompany an intro geology or graduate structural geology course.
Skills and concepts that students must have mastered
There is no single background required. The exercises, as presented, are ordered in such a way that they take the student progressively from relatively straightforward map areas to increasing complicated map areas. The first few exercises require little to know geologic background. Later exercises emphasize more advance geologic structures and relationships (i.e. folds and refolded folds).
How the activity is situated in the course
In these Google Earth Exercises (GEE), students construct a complete geologic map of each 'field area' outside of class; in class, the students display their map and discuss their observations, interpretations, assumptions, and reasoning. Students also draw stratigraphic columns and cross-sections as needed; and they determine a relative sequence of events for each 'field' area. In class, 3-4 students display and discuss maps for each exercise (usually takes about 30-45 min.); we encourage student to question their classmates. We have students construct geologic maps on transparencies and display the maps via an overhear projector. During their presentation, students must support their interpretation, and explain logic path that lead to that interpretation to the class.
Content/concepts goals for this activity
Students learn concepts of field mapping and interpretation. Students learn how to translate information discovered in the field (i.e Google Earth) to a flat map/image. This skill requires both locating oneself, and notation of various geologic information (i.e. bedding, linear trends, fold axial traces). Students learn how to recognize and symbolize structural elements. Students learn that geologic maps are interpretations; and that more than one interpretation can be valid for a single map area.
Higher order thinking skills goals for this activity
Students learn how to synthesize data, formulate multiple working hypotheses, and to how to test these hypotheses with further data collection. Students experience thinking in the three spatial dimensions, and in time, developing the concept of 4D and even nD. The knowledge, tools, and habits gained in these exercises are extremely valuable for students to attain prior to embarking on field camp and/or field mapping.
Other skills goals for this activity
Students construct a complete a geologic map for each area. Students also draw stratigraphic columns and cross-sections as needed; and they determine a relative sequence of events for each 'field' area. Students can present their map with an oral presentation, written report, or both.
Description of the activity/assignment
We use these Google Earth Exercises (GEE) in the undergraduate structural geology course. Students construct a complete geologic map of each 'field area' outside of class; in class, the students display their map and discuss their observations, interpretations, assumptions, and reasoning. This exercise promotes discussion among the students, and also provides students with the opportunity to develop speaking skills, as well as 'on-your feet' reasoning and analysis. Mapping can be done digitally using graphic software such as Adobe IllustratorTM or using hard copy images and overhead transparencies. (Digital mapping requires that the students have knowledge of working with, and access, to a graphics program such as Adobe IllustratorTM). Students also draw stratigraphic columns and cross-sections as needed; and they determine a relative sequence of events for each 'field' area. Cross section lines are included in the .kmz (Google Earth) file (not on the map images). This allows the instructor to move cross-section locations as needed. We have 3-4 students display and discuss maps for each exercise (usually takes about 30-45 min.); we encourage student to question their classmates; with time, our encouragement becomes less necessary. We have students construct geologic maps on transparencies and display the maps via an overhear projector keeping the LCD projector free to run Google Earth. Students can use Google Earth (flying to specific locations, or zooming in and out, or viewing specific locations from different perspectives) during their presentation to illustrate or support their interpretation, and logic path that lead to that interpretation to the class. This provides the opportunity for students to see how different people interpret the same area; they also learn that although each maps is different, each map tells a similar story; that is first-order relationships emerge from the family of maps constructed by their fellow classmates. After each discussion, all of the students display their maps on a side table in the classroom, providing the students with the opportunity to compare all of the maps of the same area. As a result they clearly see that all maps are different, yet each can be valid, and they also see how others handled both geologic relations, and, at a more basic level, clarity and neatness in presentation. As the semester progresses we see a sharp increase in the quality of the maps, both geologically and in terms of clarity and neatness, likely a direct result of students both viewing their classmates maps, and having their maps viewed by classmates. Peer pressure can be a wonderful learning tool.
Each exercise focuses on a different area. An individual exercise or any combination of exercises maybe used at the instructor's discretion to compliment topics in either lecture or lab. The exercises, as presented, are ordered in such a way that they take the student progressively from relatively straightforward map areas to increasing complicated map areas. We begin the geologic mapping sequence using a Venus mapping exercise available on the SERC site http://serc.carleton.edu/NAGTWorkshops/structure04/activities/3875.html
in order to get the students to feel comfortable identifying and delineating patterns; we develop concepts about material units versus structural elements (and in some cases primary verses secondary structures; please see the Venus exercise for the range of students goals, which we do not repeat here). The first Google Earth Exercise, (GEE1) follows the SERC exercise 'Visualizing Inclined Contacts' by Barbara Tewksbury http://serc.carleton.edu/NAGTWorkshops/structure/visualizing_inclined.html
. Our GEE1 exercise is included below with all credit to Barbara Tewksbury. Subsequent exercises (GEE2, GEE3, etc.) include: faults and topographic interactions; folds and topographic interactions; faults and crosscutting dikes; refolded folds. These exercises may be used in any order and/or positioning within a course. We find that both the repetition of GEE exercises, and the progression of increasing complexity of the exercises, allow the students the opportunity to develop their individual skill sets. Although mapping can be completed by the students during, or outside of class time, we find that having the students do this outside class allows each student the opportunity to move at their own pace, which seems important for our students and their learning. Discussion during class time is a critical part of the learning process.
These exercises can be easily replicated for your favorite field area or an area your think exemplifies an instructive structural style. We encourage other educators to apply this idea to other areas and submit the new Google Earth Exercises to SERC as well.
Determining whether students have met the goals
Assessment is based largely on the quality of the geologic maps, which show great improvement with additional exercises. Several of the exercises include stratigraphic columns, cross-sections, and a write-up addressing specific questions; in these cases, the quality and content of these ancillary materials figure into the evaluation. Evalautions should be mindful that there is no single right answer, although there are certainly 'wrong' answers; it is important that any evaluation allows for leeway to accommodate different mapping styles. Also instructors have leeway to modify these exercises to accommodate various goals depending on the level of the students or course level. We notice a marked improvement in almost all student maps by the second or third exercise. This improvement results, we expect, from the feedback students receive in the evaluation, but equally important, if not more important, is the learning gained through the class discussion, and the public viewing of classmates maps, and the viewing of one's maps by classmates.
More information about assessment tools and techniques.
Teaching materials and tips
A big thanks to Vicki Hansen for helping with selecting map areas, leading discussions, and endless feedback. This would not have been possible without your help.
Also thanks to Ivan Lopez for providing the inspiration for these mapping exercises and for help locating "field areas."
Venus Mapping Exercise:
Visualizing Inclined Contacts:
Teaching Geologic Map Interpretation: