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Conducting Planetary Research Here on Earth

Posted on Tue, November 26, 2019
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Jenny Whitten and I wrote a blog post two years ago about the motivation behind our first trip to Iceland to look at features called “pit chains,” which are exactly what they sound like: chains of pits that form as soil drains into cracks that open in the ground as the result of forces driven by the opening of the mid-ocean ridge. One of the challenges of planetary research is that it’s hard to find places on Earth that are good examples for landforms that form across the solar system, like pit chains: People, weather, plants, and animals all obscure the landscape in ways that we don’t have to deal with in space. That makes field measurements more complicated, but flying two scientists to Iceland is a lot faster and a lot less expensive than trying to get a dedicated spacecraft with a fancy high-resolution camera to a particular body in space. 

Our task in Iceland was to find pit chains and measure how wide they are, how deep they are, and how deep the soil was that they were forming in. The hypothesis we were testing was that the depth of the pit would relate to the depth of the soil they were in. If we were right, then we could use pit chains to test how deep soils were on other planetary bodies (note that the term “soil” here relates to any loose material on the surface, not just the stuff you put in your flower beds). 

We found them!

Time lapse of pit chains in Iceland from 1976-2018. There is a person in each image for scale, and the red circles show you the same two rocks in each image for perspective. Image credits: a) George McGill, b) David Ferrill, c) Jennifer Whitten.

Field work isn’t as easy as just coming up with an idea and buying plane tickets. For the purpose of this blog, I’ll skip all the grant proposal writing, paperwork needed for traveling with expensive equipment, and logistics of booking accommodations in a very popular tourist destination. That sounds boring.

Field work requires a lot of luggage secured with a lot of duct tape.

I also don’t think I can condense 10 days of field work into 280 characters or a single blog. So, I’m going to tell you about the top five outstanding moments of the trip:

#1) Our first morning in Húsavík, our alarm hadn’t even gone off yet when I kept hearing this ringing noise that I was trying really hard to ignore because jetlag is real. Finally realizing it was the doorbell, I rolled out of bed in my Star Wars R2D2 jammies and sleep mask askew. I answered the door to a police officer speaking to me in Icelandic. Forgetting my manners, I managed to stammer “I’m sorry, do you speak English?” He said “Is that your vehicle? Can you park it over there?” “Sure?” I said, thinking I had some time before I had to move the car. But the officer meant right now. Trying to keep his composure and not laugh at my confusion and state of disarray, he said “thanks” and that was that. What a great start to Day 1. 

Keep reading, it’s only going to get better. 

#2) It’s about a 6 hour drive from Reykjavík, where we landed and picked up our very sturdy rental car, to our home base in Húsavík in northern Iceland. Our 4x4 rental car took the paved roads with no problem. Thirty minutes into our first morning in Húsavík (after the encounter with the police officer) we were heading south towards Mývatn to find our first field site of the trip. Driving up a hill, Jenny told me she couldn’t accelerate. I rolled my eyes at her, because we were driving. Up. A. Hill. Joke was on me because immediately the car engine made a noise you NEVER WANT TO HEAR. We stopped the car, and by that, I mean we stopped the car in the middle of the road because there aren’t any shoulders on the road. The car would not re-start and that was that. Oh, and we had no cell phone coverage, we were 30 miles from anywhere, and there was a lot of black goo under the car and it was a Sunday on a three-day weekend. A lovely little family stopped to pick us up and drive us to Mývatn where there was a tourist center where we could call for roadside assistance. We were picked up by one of the local contractors who I’m confident didn’t totally take us seriously until he drove past our car. He never even bothered to look under the hood. Black goo is never a good sign. He helped us load our equipment into his truck and we guided him to our home base in Húsavík (45 minutes away) because… well, we couldn’t pronounce the name of the street where our home base was. We are still so grateful for that little family who picked up some stranded geologists on their holiday.  

  

The number of times Jenny had to fill the tires should have been our clue that our car was going to fail us. 

#3) Our first trip to Iceland was in August, but our second trip was in May and it turns out May is lambing season. Driving around the country side watching tiny lambs romping in the fields is about as good as it gets. Because baby animals are very cute. 

Sorry for the terrible photo of sheep—but they are shy and hard to photograph from the car, baby lambs are even harder.

#4) One of our field sites was on this sandy delta east of Húsavík. We had a tiling probe (steel rods with steel hammer) that we could pound into the ground to measure the thickness of the soil. When we could no longer hammer it deeper into the ground, we interpreted that as the total depth of the soil. It took two hours to hammer five meters worth of rods into the soil, and NEVER hit bottom. It took another two hours to hammer the five meters worth of rods out of the ground. When we were detaching the last rod from the hammer we lost our grip on it and floooooshp! (say it out loud, it’s kind of the sound it made). It got swallowed up like it was in Lightening Sand. We dug in the sand for a while trying to retrieve it, until we remembered: we packed extra! (Always be prepared.)

Jenny hauling around the GRP and me being tired but still taking a selfie with the tiling probe.

#5) After spending four hours pounding steel rods into, and then out of the sand (did I mention it was drizzling the whole time?) Jenny and I had a heart-to-heart: Part of the measurements we were taking were using a Ground Penetrating Radar (GPR) which allows us to essentially image the subsurface (so we could maybe see how deep the soil is). If the ground is too wet, then the GRP can’t work well. We made the most of the cold, drizzly day and do some GPR work in case the rain didn’t let up for the rest of the trip, and the ground became too wet. After a snack break, and some pump-up music blasted from the car (no one was around so we thought it was ok), Jenny booted up the GPR so we could collect data in case the rain never let up. 

See, this is the thing about field work: A bad apple of a rental car can lose you a day or two, the weather can surprise you and threaten to render your measurements impossible, or it can just be really cold. Science and life have a lot in common. It’s always best to dress in layers, bring lots of snacks, wear practical shoes, and always remember that baby lambs might just be the highlight of the day. Science is hard, science in the field is a different kind of hard, but teamwork always makes it better.

A sunny day! Selfie with a set of water-filled pit chains as the background.

Jenny and I wrote up our Iceland results recently in a paper published in the Journal of Geophysical Research. We found that we can relate pit depths and diameters and we can use them to estimate the depth of the soil they form in. We are now working on another paper where we use pit chains as a tool to map out the distribution of soil depths across Saturn’s moon Enceladus. We’ll be back to tell you that story later. 

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