Structural Geology & Tectonics @ ETHZ

Authored by Lonnie Hufford.

When asked what you did over the summer, it is common to talk about the camping trips, picnics, or vacations you took. However, as a geologist who does field work you can almost always respond with, “I was in the field.” What this statement means is completely different to each geoscientist, as it may encompass months in the field mapping alone with little food, working out of hotels, trudging through the snow, or a vast amount of other scenarios. That sense of adventure and variety is what brings us to want to work in the field. What I am about to describe to you is our summer field work. We lived.

From the middle of June to the middle of July, I spent time working near Anchorage and Homer, Alaska with Dr. Whitney Behr, Dr. Zoe Braden, and on the last leg of our journey, Dr. Mark Helper. We are studying the accretionary wedge portion of a subduction zone off the coast of Alaska on the Kenai Peninsula. To quickly summarize, we are interested in the rheology of the shallow subduction interface and what parameters affect the rheology, the timing of the units to better understand their emplacement and kinematics, and the translation and reactivation of faults and their connection with the exhumation of the adjacent rocks which are now exposed. Personally, I am especially stoked on the marbles and blueschists I am working on for my project, but that’s a whole other blog post (or chapter in a thesis).

Our goals were to structurally map, collect samples (~181 kg or 400 lbs worth in the end), and describe the field areas we had decided to visit based on the prior year’s work. To accomplish these goals, we had tools that made this summer field work distinct because they had a 21st century spin: iPads and drones. We said goodbye to paper maps and embraced the future as we created maps by taking photos with the drone and loading them into the iPads. With this technology, we were able to create up to date images to map with while controlling all the parameters you always wished you could have when out with your paper and colored pencils. This allowed us to be more efficient than the standard field setup by keeping our maps, measurements, notes, and photos all within our compact tablets. It made keeping track of everything a breeze, which was good because we needed to focus our attention on the rocks and other… logistical challenges.

The field areas we worked on are fantastic places and have exciting rocks. They also have other exciting things – wildfires, maniacal seagulls, ~9 m/30 ft tidal differentials, frigid glacial waters, crumbling rocks, and outcrops that are beautiful and right on the edge of an extremely busy highway. These are the types of logistical challenges you face in the field while in Alaska – when the smoke is so heavy that you can barely see in front of you while driving, seagulls dive bombing you, having small windows of time where your boat can make it through the lagunal channel without getting stuck, or the tide almost swallowing the gear you forgot on an outcrop, sweet good mornings from a baby bear in your camp when you are sleeping, having your packrafts begin to deflate in a glacial lake because you didn’t wait long enough before paddling out, thinking you have two more hits with a rock hammer before the outcrop tumbles down on you when you actually only have one, and running across the highway like an Olympian with a bag full of rocks trying not to get hit by speeding cars. You can only plan for so much.

That’s how I like to describe my summer field work. I like to talk about the rocks and faults we found, the challenges of extracting data and interpreting it at small and large scales, and what we should look for next year…. BUT, I also like to describe my field work with what happened while looking at the rocks, because that’s all part of the experience!