Teaching geologic map interpretation

Barbara Tewksbury (Hamilton College)

The approach that I used to use

Define strike and dip and the various types of contacts. Help students visualize with Play-Doh.
Start with planar contacts in areas having no topography; use lots of Play-Doh and paper models of inclined planar contacts to teach cross sections and apparent dip.
Add topographic relief, and teach about the outcrop pattern of horizontal contacts, move on to vertical contacts, and then address inclined contacts and derive the rule of Vs.
Bring out real world geologic maps, and have students apply what they have learned to interpret the maps and to draw cross sections.
Move on to maps with folded contacts.
Give students the opportunity to do their own mapping in the field.

Raplee Anticline, Monument Upwarp, near Mexican Hat, Utah (37 09 15.44N, 109 49 20.24W). Click image to enlarge.

Click image to enlarge.

Emphasize mapping before map interpretation in order to help students visualize, rather than memorize.
Start by having students do geologic mapping in Google Earth before they know anything about strike, dip, or types of contacts.
Have students work first with inclined units and contacts in areas with topographic relief, using Google Earth 3D view to develop an understanding of dip.
Have students sketch simple cross sections of their own geologic maps and use Google Earth 3D view to help them visualize the relationships.
Derive strike after students understand dip.
Have students work with vertical contacts next, then horizontal contacts, and, finally, folded and faulted contacts.
Give students lots of practice in mapping in Google Earth and creating their own cross sections in areas of increasing complexity.
Follow with interpretation of existing geologic maps coupled with use of maps in the field.

Go to the first step: Visualizing inclined contacts