Some examples of essay-type questions:

• What is the difference between the tholeiitic and calc-alkaline magma evolution trends? Fractional crystallization of what mineral is primarily responsible for the distinction between these trends? At which plate tectonic setting is each trend most common? Why? Plot a calc-alkaline trend on an AFM triangle.
• What are the most common volatiles in magmas? How does their solubility vary with magma composition? How do volatiles affect the physical properties (density, viscosity) of magma? How do volatiles vary in different tectonic settings?
• What are the major variables that affect the physical properties of magmas and what effect does varying each have on those physical properties? Illustrate plots of density vs. a) temperature or b) wt% H₂O for basalt, andesite, and rhyolite at 1 bar pressure.
• Illustrate a plot of viscosity vs. temperature (at 1 bar pressure) for basalt, andesite, and rhyolite. How does the crystalline structure of the silicate minerals affect the viscosity of different compositions of magma? How does water content affect viscosity of a magma?
• What is a solidifaction front and how does it affect the ability of a magma to flow or convect? Identify and describe five differentiation processes in magma chambers. Identify and describe four magma chamber processes revealed in the pluton rock record. Illustrate and describe how a magmatic system can be envisioned as a mush column.
• What mineral relations can be evidence of magma eruption rates? How deep are magma chambers that feed volcanic eruptions? What evidence supports this interpretation?
• How do exsolving gasses (bubbles) affect magma flow and eruption styles? Can dry silicic magmas erupt in the absence of an external forcing mechanism? Why or why not?
• How does volatile exsolution drive pyroclastic eruptions? What factors dictate the style of a volcanic eruption?
• In what plate tectonic settings do volcanic eruptions occur? What is the range of durations of eruptions and when does peak activity most commonly occur during an eruptive sequence? Are eruptions getting more frequent? Why or why not? What is the relationship between frequency and magnitude of eruptions at any given volcanic center?
• How is eruption magnitude related to intensity? Are they the same or different? Explain.
• What is the global distribution of eruptions on an annual basis? Has volcanic activity varied over geologic time? What type of events account for the largest pulses of volcanism since the Mesozoic?
• Learn the Big Chart. Live the Big Chart. Love the Big Chart.