From the Field: January in the Andean Southern Volcanic Zone

Author: Emily Mixon (MS expected 2020, PhD expected 2023)

I spent countless hours during the fall of 2018 looking at “my” volcanoes on GoogleEarth. I would add digitized points where previous papers had collected data, I would zoom all the way in and squint and draw squiggly lines–“is this a sendero? is it a road? is it an impassable gully?” So when I stepped off the plane in Temuco in January, I thought I had a concept of what I would see over the course of the next month of sampling work. I was wrong. Our first day on the road to Villarrica Volcano, I was immediately overwhelmed by the true scale of the landscape. The Andean Southern Volcanic Zone stretches for hundreds of kilometers—huge active volcanoes dating back to the Early Pleistocene are mere pin pricks along the range crest. Over the next 5-6 years I will, alongside an interdisciplinary team, work to solve some of the mysteries of these distinct and complex volcanic systems. Specifically, using 40Ar/39Ar geochronology, 3He surface exposure dating, whole rock geochemistry, and thermodynamic modeling, I will seek to reveal the behavior of these systems over the last two glacial maximums. But before I can get started on any of that, I needed to pick up some rocks. It was time to go hiking!

Our field team, which included me, my advisor Brad Singer, one of my committee members, Shaun Marcott, and Ben Edwards, a lava-ice expert from Dickenson College, spent January rattling around 4×4 roads and hiking up and down thickly forested ridges and scree covered slopes to hammer pieces from lava flows. On bad days, we would spend hours whacking through thick rainforest, no rocks in sight. On good days, we had a helicopter.

Field work in a new landscape has a steep learning curve (pun intended!). I learned a lot on this trip about sampling strategy, lava/ice morphologies, glacial landforms, and volcano eruptive behavior. I also learned that my abilities to hike, to hammer, and to talk about ideas with other scientists extend far beyond my perceived comfort zone. Now I’m home, with over 100 kg of samples to prepare, lots of data points to add to my digital maps, and plenty of new skills to tackle. I feel extremely fortunate to have a project that allows me to visit such a unique landscape, but I would encourage any geologist to get out and see the rocks around them! Whether you’re looking at volcanoes in Chile, drumlins in Green Bay, or quartzite in Baraboo, I promise that interacting with new rocks will hone your observational skills, strengthen your confidence, and maybe lead you to new science questions!

If you ever want to plan a geology hike, talk about fieldwork abroad, or discuss volcano/climate interactions, you can find me in Weeks A347 (or in the basement, crushing rocks!).

Emily Mixon