Stop 1: We started the day with an overview of the north side of the caldera from the lookout at Bald Mountain. We also had a chance to see what a volcanic eruption from the Mono Craters would look like, as a result of a fire near Mono Lake! Fortunately the fire was brought under control fairly quickly as a result of expert work by firefighters.
Stop 2 & 3: We put our newly acquired pumice and lithic counting skills to good use in examining the northern ignimbrites. The crystal-rich pumices are pretty amazing! Here we learned that crystal-poor Bishop rhyolite was erupted mainly from the southeastern vents, whereas crystal-rich material was erupted from the vents along the northern margin of the caldera. We also observed an increase in the proportion of lithic clasts made up of recycled rhyolitic tuff.
Can you spot the ignimbrite?
One of the prized mixed pumices.
Spot 4: Glass Mountain Obsidian (a group favorite)!
Artistic moment of the day…