Physical and Chemical Variations Along the Central American Volcanic Arc

Kent Ratajeski, University of West Georgia
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The Central American volcanic arc displays large arc-parallel variations in chemical composition that yield important clues concerning the complex origin of magmas in subduction zones. In this exercise, students use data compiled for the NSF MARGINS program to compare heights, volumes, and whole-rock compositions of 39 Quaternary volcanic centers along the Central American arc, together with crustal thicknesses, to assess the possible sources of the magmas and the petrologic processes that have modified them prior to eruption.

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Learning Goals

Content/concepts goals for this activity: Students who complete this exercise should be able to:
  • make and test hypotheses linking variables such as magma composition, crustal thickness, volcano height, and sediment subduction

Higher order thinking skills for this activity: This exercise requires students to formulate hypotheses and to compare/contrast data.

Other skills/goals for this activity: Obtaining and using data from online databases like those at the NSF-MARGINS portal informs the students about the powerful resources that have recently become available to the scientific community via the creation of digital cyberinformatics and cyberinfrastructure. Carefully guiding students into these databases, through the various steps required to screen, download, import, and use their data, students are empowered to think and act like scientist in tangible and practical ways.

Context for Use

This activity can be used as a supplementary exercise to complement lectures on subduction zone magmatism in an undergraduate- or graduate-level petrology course. It may be completed in or out of class.

Description and Teaching Materials

In this online activity, students download a dataset relating to various aspects of the chain of volcanoes along the western coast of Central America. They then graph pieces of the data in Excel and analyze the results for trends in various measured quantities.

The instructions for students and location of the dataset for this activity can be found where it was originally published by the author as a part of the Integrating Research and Education project:

Teaching Notes and Tips


Students are presented with a series of questions to answer during this exercise. It is up to the instructor how the students' data might be evaluated. This exercise might to used to form the basis for an open-ended group discussion.

References and Resources