Graphing Chemical Data to Identify Fractional Crystallization
Summary
Students are given major-element, whole-rock chemical analyses from ten samples of lava from the 1868 eruption of Mauna Loa. They do not know sequence of eruption, only that the lavas came from the same volcano. Students are asked to evaluate the hypothesis that the observed chemical variation is due to the fractional crystallization of olivine. The hypothesis can be tested any of a number of graphs. Several examples are given in the accompanying Excel workbook.
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Context
Audience
This activity is designed for a required course in petrology for majors (sophomore or junior level).
Skills and concepts that students must have mastered
Students should be familiar with basic igneous processes.
How the activity is situated in the course
This is a stand-alone exercise.
Goals
Content/concepts goals for this activity
Students are asked to evaluate the hypothesis that the observed chemical variation in lava is due to the fractional crystallization of olivine. The hypothesis can be tested any of a number of graphs (provided).
Higher order thinking skills goals for this activity
This activity involves data analysis.
Other skills goals for this activity
Description of the activity/assignment
Students are given major-element, whole-rock chemical analyses from ten samples of lava from the 1868 eruption of Mauna Loa. They do not know sequence of eruption, only that the lavas came from the same volcano. Students are asked to evaluate the hypothesis that the observed chemical variation is due to the fractional crystallization of olivine. The hypothesis can be tested any of a number of graphs. Several examples are given in the accompanying Excel workbook.
Determining whether students have met the goals
Teaching materials and tips
Other Materials
- Mauna Loa Problem Set (Microsoft Word 34kB Jul14 03)
- Mauna Loa Worked (Excel 53kB Jul14 03)