Guest post by Marcus Hill (Geology Undergrad at Oberlin College)
For the first part of my winter term project this year I was able to help take samples at a few sites within Northern Arkansas. The project began as way for Dr. Amanda Keen-Zebert and Dr. Stephanie Shepherd to return to home and do some investigating in their backyard and developed into a hugely collaborative endeavor. Professors, grad students and undergrads (hey, thats me!) from different institutions across the US have expressed interest and offered to help in whatever way possible. The goals of this trip in particular were to obtain OSL samples from several terraces within some federally recognized park sites and also to perform Terrestrial Lidar Scanning (TLS) on bluffs that were of interest.
While we flew in on Wednesday night, we didn't make it back to the cabin until around 1AM, so there wasn't anytime for introductions or anything like that. So the next morning after breakfast we had a more formal sit down chat where everyone had the chance to introduce themselves and learn about the project. After that was done we loaded up the cars with supplies and headed out to the first site, Steel Creek. This location was only a 15-20 minute drive from our cabin, which was really nice as the day became brutally cold very quickly. Dr. Keen-Zebert had intended to spend the day both digging and scanning but as it was such a easily accessible and popular location for campers, we didn't know if we had permission to dig. So onto scanning then. The scanner is a machine that looks like a larger than usual lunch box with a rotating camera embedded on the top, which has to be mounted and leveled on a tripod. This machine also costs upwards of $40,000, so you want to make sure that tripod is firmly planted into the ground. Scanning went well enough for most of the morning, but as snow and the temperature started falling, the batteries started failing. After running back and forth between charging stations and the scanner for nearly an hour we had to call it quits.
Friday and Saturday the weather was still cold but we were able to keep warm by digging! After making the two hour journey to the Margret White site, Dr. Shepherd and Keen-Zebert showed us the locations for the two trenches. There isn't a whole lot to say about these days, they just included a lot of physical labor. On Saturday, before we started digging we did get to do a small field trip and explore the surrounding region, learning about the different rock types that are present within the local environment.
On Sunday we had a little bit of a reprieve after digging for two days and were able to learn about and see how Optically Stimulated Luminescence (OSL) sampling works. Its a process which takes advantage of impurities in the structures of quartz rich samples. Specifically Amanda was looking for a sample which doesn't have a uniform composition and holes were allowed to develop at the molecular level. These holes allow electrons to get stored when the sample is not in the presence of light. The process is somewhat analogous to charging a battery.
Monday we went back to the Margret-White trenching site, this time accompanied by Amanda and Stephanie's professor from grad school who specialized in soils. The weather had also made a complete 180 and turned out to be around 60-70 degrees.
Tuesday we had the fun job of refilling and erasing all of our hardwork on the trenches.
We then closed off the week by going back to the Steel creek site and helping finish off the TLS work that we could not do because of the weather earlier. The process involved setting up the scanner with the right parameters and letting it do its thing for anywhere from 30-40minutes. In that time you could do anything you want, Malcolm and I skipped a lot of rocks, but you just had to make sure to not be in the field of view while the scanner was going.
Well, that was pretty much the extent of the trip, I had an absolute blast and if this at all interested you, there is a facebook page, Buffalo River Geoscience, set up which posts periodic updates about the project. Until next time, Marcus