Magma Degassing, Crystallization, and Eruption style: Undergraduate Labs and Modules
This group of lab activities and homework modules focuses on magma crystallization, degassing, and eruption style. The activities include those appropriate for lower-level high school or college geology courses, as well as for upper-level courses focused on physical volcanology. The collection also includes two Google Earth kml tours that can be part of a lab or homework activity developed by the user, or as part of a virtual field class. See the links below for more information about each of the activities included in this group:
- LEGO® Magma Crystallization Activity - This activity represents a very basic exercise exploring the chemical feedback between a growing crystal and the resulting change in melt composition surrounding it. Students use legos (or any other type of building block toy) to create a compositionally zoned "plagioclase" crystal to examine how magma composition (in weight percent SiO2) changes as a function of magma crystallization.
- Magma Degassing and Eruption Style 1 - Students explore how vesicles preserved in different volcanic rocks can be used to estimate the gas content of the magma. The activity involves calculating rock vesicularity and the results are applied to simple determinations of eruption style.
- Magma Degassing and Eruption Style 2 - Students work with real data collected from samples from the 2008 eruption of Okmok volcano, Alaska, to explore how magma gas content can be estimated from the porosities of volcanic rock samples from explosive eruptions. They calculate bulk density and porosity as a proxy for the gas content of the magma at the moment of fragmentation, estimate the permeability of the magma via percolation theory, and use their data and models to answer questions about the mechanisms of eruption and eruption style.
- Google Earth Tour #1 - Degrees of Welding in the Bishop Tuff - This Google Earth kml file includes outcrop photos and detailed descriptions of the Bishop Tuff collected along a LADWP access road that leads down into the Owens Gorge, in Eastern California. This kml file can be incorporated into lectures, labs, homework activities, or virtual field trips as desired by the instructor.
- Google Earth Tour #2 - Obsidian Dome Outcrop Tour - This Google Earth kml file includes outcrop photos and detailed descriptions of the different mapped lithologies from Obsidian Dome, in Eastern California. Obsidian Dome represents a silicic lava flow that erupted in 1350 CE (Millar et al., 2006) as part of the series that created the Inyo-Mono domes along the margins of Long Valley Caldera. This kml file can be incorporated into lectures, labs, homework activities, or virtual field trips as desired by the instructor.
About this Project
This collection of lab activities was developed and used by the author in undergraduate classes at the University of Alaska, Fairbanks. The activities come from the volcanoes lab section of GEOS 120: Earthquakes, Glaciers, Volcanoes course and the GEOS 406 Volcanology course for upper division Geology and Geophysics concentration majors. The collection is sponsored by NSF funding from grant EAR 1650185