What's in a Name? Volcano Edition
10.28.2021 - By PlanetGeo: The Geology Podcast
In this episode, we discuss the categories - or different types of volcanoes in the world. We begin by discussing how the traditional categories, as found in most textbooks, are not adequate. There are too many exceptions to the rules. So we begin by discussing the typical 3 - Shield, stratovolcanoes, and cinder cones. Then, we expand the categories to include rhyolite caldera complexes (often called supervolcanoes), monogenetic fields, flood basalts, and mid-ocean ridge systems. Even with this expanded category list, not all volcanoes fit nicely. Each volcano is its' own snowflake.
With volcanoes, there are exceptions to our categories and some will fall into more than one category. Many students get confused by this because the 3 category system doesn’t allow for exceptions. I think this is Ok, but only if they’re taught that exceptions definitely exist - OR - let’s be more extensive with our categories. To be honest, I’m bothered by the exclusivity of the “3” type system. AND, even with a more extensive category list, there are exceptions and students need to know this is OK.
With each type, we discuss it's geomorphology, the eruptive personality, the tectonic setting, and an example or tow of where they occur.
We also spend some time discussing the plumbing system of volcanoes and how complicated this can be. If we can begin to understand the plumbing system, then we can begin to study how magma traverses the crust. This traverse can lead to a diversity of magma composition - even within the same volcano. This discussion is crucial to student understanding.
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