Wakemup Pluton

class='author'>Basil Tikoff, University of Wisconsin-Madison
Naomi Barshi, University of Wisconsin-Madison
Carol Ormand, SERC, Carleton College
Author Profile
Initial Publication Date: March 10, 2020 | Reviewed: December 10, 2020

Summary

Students work through a set of questions about a geologic map of an igneous intrusion and surrounding rock units. These questions focus students' attention on the topography, geomorphology, lithology, and structural geology of the region. When they have figured out the geology to the best of their abilities, we show them Play-Doh models of the pluton and country rock in various stages of erosion.

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Context

Audience

200-level undergraduate course, "Introduction to Geologic Structures." This course is a pre-requisite for most upper-level undergraduate geoscience courses in the core curriculum, including Structural Geology. It has a pre-requisite of an introductory level Geology course.

Skills and concepts that students must have mastered

Students need to be able to "read" a geologic map: to infer topography from topographic contours, recognize geomorphic features related to glaciation, recognize igneous and metamorphic rock names, and infer igneous intrusion from lithologic and structural clues.

How the activity is situated in the course

This exercise builds on previous course activities and lectures, which have introduced all of the relevant concepts, rock types, and processes.

Goals

Content/concepts goals for this activity

Students will decipher the geologic history of an igneous intrusion in northern Minnesota.

Higher order thinking skills goals for this activity

Students will be able to construct a schematic cross-section and make reasonable interpretations of the geologic history of a region based on a geologic map.

Other skills goals for this activity

3D spatial visualization, including mentally connecting sparse outcrops.

Description and Teaching Materials

Students answer the questions in the attached handout. We also have rock samples of the main lithologies present in the map area. When students have worked through most of the questions, we show them the two schematic Play-Doh models of the region at different stages of erosion (see photos), ask them how these models are related to the map, and answer any questions they have about the models and map.

Wakemup Pluton map activity (Microsoft Word 2007 (.docx) 107kB Dec10 19)

Science of Learning: Why It Works

Three-dimensional models can help to improve students' understanding of geological phenomena. Physical models, such as playdough models, serve as analogies to geological features and geologic maps. Analogies support the development of spatial thinking skills by allowing the student to draw from their knowledge and apply it to new cases (e.g., Gentner 1983). For example, students can reason from what they can experience when carving off pieces of playdough to how erosion will reveal geological structures). Analogical learning also applies to "mapping" -- that is, relating -- the features of models onto real world phenomena (e.g., this layer of playdough corresponds to a layer of sandstone). Physical models provide analogies to real-world phenomena, support cognitive offloading, and promote spatial accommodation.

Practice constructing spatial analogies can help students develop the mental models that allow them to recognize new cases of familiar concepts in the field. When instructors provide accurate physical models of geologic features, students can self-assess their understanding by comparing their mental model -- or their own physical model -- to the instructor's physical model. When students make their own physical models, these models serve as a means of "inscription," in much the same ways that mapping and sketching do: they allow for students to record their conceptual understanding of a natural phenomenon (Mogk and Goodwin, 2012). However, unlike mapping and sketching, a playdough model allows for this record to be three-dimensional, like the phenomenon itself, which can reduce the cognitive demands inherent in the process of inscription by reducing the need to generate a 2D representation of 3D space (Newcombe, 2012). In addition, physical models support spatial accommodation: when a student compares their (mental or physical) model of a phenomenon or region to their instructor's model and recognizes a difference between the models, the student is prompted to revise their mental model (Davatzes et al., 2008). When the change required is spatial the student may use the feedback directly to revise the model. When the change is significant, the student may need to completely discard their old model and construct a new one. Playdough models of geological structures can thus serve as the basis for improved mental models.

Teaching Notes and Tips

We do this activity as a multi-day in-class exercise, but it could just as easily be a lab exercise.

Assessment

Students hand in their answers to the questions on the student handout.

References and Resources

Map:

The map for this activity is Bauer, R. L., 1985. Norwegian Bay Quadrangle, St. Louis County, Minnesota. Minnesota Geological Survey, Miscellaneous Map Series, Map M-59.

Additional References:

Davatzes et al. (2018). Learning to form accurate mental models. Eos, 99, https://doi.org/10.1029/2018EO091643. Published on 07 February 2018.

Gentner, D. (1983). Structure-mapping: A theoretical framework for analogy. Cognitive Science, 7(2), 155–170.

Mogk and Goodwin (2012). Learning in the field: Synthesis of research on thinking and learning in the geosciences, in Earth and Mind II: A synthesis of research on thinking and learning in the geosciences, edited by Kim A. Kastens and Cathryn A. Manduca. GSA Special Paper 486:131-163. DOI: 10.1130/2012.2486(24)

Newcombe, N. S. (2012). Two ways to help students with spatial thinking in geoscience. Geological Society of America Special Papers, 486, 85-86.