Where Did That Quartzite Clast Come From?: A Problem-Based Provenance Study

Andrew Hanson
,
University of Nevada Las Vegas
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Summary

Students conducted microprobe geochemical provenance studies on quartzite clasts contained within a Tertiary conglomerate in southern Nevada, as well as quartzites that occur in the pre-Cambrian-Mesozoic stratirgraphy in the region. This project was carried out by an undergraduate Sed/Strat class. Incorporating this research into our undergraduate class resulted in two significant things that had been missing in previous classes: true excitement amongst the students related to research, and multiple opportunities for assessing and improving students writing skills.

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Context

Audience

This project was completed during a semester long senior-level undergrad sed/strat class.

Skills and concepts that students must have mastered

How the activity is situated in the course

This project spanned the entire class.

Goals

Content/concepts goals for this activity

The project was designed as a pilot study of the trace element geochemistry of quartzites to determine their usefulness with regards to provenance.

Higher order thinking skills goals for this activity

Students manipulated and analyzed geochemical data within Excel; students had to find relevant literature related to the stratigraphic unit they were chose and develop hypotheses related to whether it could have contributed detritus to the Tertiary conglomerate with quartzite clasts of unkonwn origin; students had to evaluate and synthesis the data and determine whether their stratigraphic unit could have been a source for quartzite clasts.

Other skills goals for this activity

Students learned how to use online literature search engines; learned how to format bibliographies in GSA Bulletin format; learned how to write an abstract, intro, background, methods, results and discussion, and conclusions; learned how to use Powerpoint, learned how to use Adobe Illustrator; learned how to make a scientific poster; gave oral presentations both in-class and at a poster session;

Description of the activity/assignment

Students selected one of six stratigraphic units that nominally could contribute quartzite clasts to a Tertiary conglomerate in southern Nevada. They read Goetze and Lewis's (1994) paper on using trace element geochemistry on quartz sands then performed a literature search related to their unit and read relevant papers related to their unit. Students collected samples from their stratigraphic unit and prepared them for microprobe analysis. They reduced the data from their samples and then analyzed the data as a combined set to determine if their units geochemical signature was unique compared to other units. They then statistically compared their unit to the clasts of unknown origin from the Tertiary conglomerate. This project gave the students experience in finding conducting a literature search, collecting and preparing samples for analyses, manipulating data within Excel, comparing data statistically, explaining their data to other students int he class, and preparing talks and a poster.

Determining whether students have met the goals

Assessment was based upon successfully completing the following tasks: 1. turn in a bibliography formatted in GSA Bulletin style that contains 9-10 citations related to their stratigraphic unit, 2. write (then revise) an Introduction, 3. write (then revise) a Geologic Background, 4. collect samples for analyses, 5. prepare samples for microprobe analyses, 6. reduce data and compare to other units and the unknown clasts, 7. produce a poster and present at a symposium, 8. write a Results, Discussion, and Conclusion section and turn in a final paper, and 9. prepare a Powerpoint presentation and give a talk during the final lab period.

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Other Materials

Supporting references/URLs

Goetze, J., and Lewis, R.,1994, Distribution of REE and trace elements in size and mineral fractions of high-purity quartz sands: Chemical Geology, v. 114, p.43-57.