New Views of an Old Continent: A Tectonics Lab Exercise Using Geophysical Maps of Australia

David Greene, Denison University

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Summary

In this lab activity students are given five different map views of the continent of Australia: Geology, Gravity Anomaly, Magnetic Anomaly, Digital Elevation, and Satellite Image, and asked to investigate and interpret these different data sets. The primary goal is to introduce students to the potential of geophysical data for regional geologic and tectonic investigations.

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Context

Audience

This exercise is used in a 200-level undergraduate course in Global Tectonics. Students in this course are generally sophomores and juniors who have had at least two previous geology courses, but often not including structural geology.

Skills and concepts that students must have mastered

Basic knowledge of geology. Activity can be done at many levels, from simple pattern recognition to sophisticated analysis.

How the activity is situated in the course

Stand-alone lab exercise.

Goals

Content/concepts goals for this activity

Introduce students to geophysical map data, especially magnetic and gravity maps, as alternative ways to image and investigate regional tectonics.

Provide experience in analyzing and combining multiple data sets to interpret regional geology.

Elicit curiosity about large scale features of the Earth's surface, and an interest in different methods to investigate them.

Higher order thinking skills goals for this activity

Other skills goals for this activity

Description and Teaching Materials

I provide to students poster size maps of the Geology of Australia, the Magnetic Map of Australia, and the Gravity Anomaly Map of Australia. These are available in various forms and resolutions from Geoscience Australia (see link below), in printed form for quite reasonable prices or as free downloads. I include here links to digital files at moderate resolution. I try to have a set of maps for each 3 students.

I also post geographic, digital elevation, satellite image, and radiometric maps to provide more information and alternative views.

I provide the students with 2 handouts (links below): a sheet of general instructions, and an excerpt that includes some very basic information on the different geophysical maps.

The emphasis in this exercise is on exploring unfamiliar data sets and new ways of investigating regional geology and tectonics. I therefore spend very little time on the details of geophysical data acquisition and limitations, and none on quantitative analysis.

Geophysical Maps of Australia handout (Microsoft Word 30kB May14 12)
OZ SEEBASE Description of Geophysical Data Sets (Acrobat (PDF) 5.3MB May14 12)




Assessment

I interact with students during lab, and examine and grade the maps and question responses they turn in.

References and Resources

The primary source of geological and geophysical data for Australia is Geoscience Australia:
http://www.ga.gov.au/products-services/maps/maps-of-australia.html

Example of magnetic anomaly data used for tectonic interpretation:
Greene, David C., 2010, Neoproterozoic rifting in the southern Georgina Basin, central Australia: Implications for reconstructing Australia in Rodinia: Tectonics, v. 29, no. 5, TC5010, p.10-20.
http://www.denison.edu/academics/departments/geosciences/neoproterozoic2010.pdf