HR: 0830h
AN: ED41C-1183    [PDF]
TI: Using Observations to Interpret Magma Processes in the Sierra Nevada: An Undergraduate Petrology Laboratory Exercise
AU: * Wenner, J M
EM: wenner@uwosh.edu
AF: University of Wisconsin Oshkosh, Geology Department 800 Algoma Blvd, Oshkosh, WI 54901 United States
AB: Undergraduate igneous and metamorphic petrology is often one of the few courses in which students use field, thin section, hand sample and geochemical observations to interpret a suite of related rocks. Many students may not have encountered the idea of separating observation from interpretation prior to petrology; yet being able to distinguish these is an important skill for any budding petrologist to learn. Labs that require students to integrate abstract concepts from the lecture portion of the course to present a coherent story based on observations are essential to producing students that are well versed in petrology. A capstone-type lab allows students use many of their recently acquired skills to solve real problems in petrology. These integrated labs can take a number of forms from a short lab looking at a few related thin sections, to a multi-week lab with specified tasks, to a semester-long project culminating in a paper or a presentation. For the past few years, I have used a suite of rocks from the Sierra Nevada batholith to give petrology students a capstone experience for the igneous portion of the course. Students are given thin sections with hand samples, a map and a table of geochemical analyses and asked to record hand-sample and thin section observations with the idea that these will be used to understand processes that were active during batholith generation. Because students are given geochemical analyses, they are also expected to experiment with the use of graphs (e.g., Harker and spider diagrams) to better understand tables of geochemical analyses. The students use observations about rocks and geochemistry to build a coherent story around these rocks; the final product is a short paper in which they use petrographic observations and geochemical diagrams to back up their interpretations. Although the lab presented is specifically designed around a set of thin sections housed at the University of Wisconsin Oshkosh for an upper level course, the lab is highly adaptable. I present some options for adapting this lab to any set of thin sections and hand samples with associated geochemical analyses. This lab can also be tailored to a variety of skill levels - from 2nd year introductory petrology to a graduate course.
DE: 1000 GEOCHEMISTRY (New field, replaces Rock Chemistry)
DE: 1040 Isotopic composition/chemistry
DE: 3640 Igneous petrology
DE: 3655 Major element composition
DE: 3670 Minor and trace element composition
SC: Education and Human Resources [ED]
MN: 2003 Fall Meeting