Welcome to the blog for the Oberlin College Geomorphology Research Group. We are a diverse team of students working with Amanda Henck Schmidt on geomorphology questions. This blog is an archive of our thoughts about our research, field work travel notes, and student research projects. Amanda's home page is here.

Friday, December 23, 2016

And Now for Something Completely Different: Archaeology Post

Hey all,
My name is Lucas Brown, and I was doing some research this last semester with Amanda advising me, so she asked that I do a short post about my findings.

Over the course of this last semester I was doing a hydrology study of an area in Italy that has been dug by archaeology professor Susan Kane since the mid 90's. This area has been inhabited for thousands of years by various cultures; first the Samnites, then the Romans, and now modern Italians. In ancient times the area was heavily terraced, so I was attempting to find out if the ancient terracing had affected the watersheds and general hydrology of the area. To do this I used a modern DEM of the area and also created another DEM using data that has been collect on the local terraces. I then created two sets of watersheds to see if they differed.

I found that several of the watersheds that had many of the terraces within them did have some changes, showing that the terraces did affect the local hydrology. Below are several figures that show the general area and also the watersheds that had changes.
The Monte Pallano area within the Abruzzo region

Base DEM watersheds

Terraced DEM watersheds

Sunday, December 18, 2016

Hey everyone,

As the semester has come to an end, so has my time in the Geomorph lab until next Fall. Like Chloe, I'll be studying away in New Zealand next semester. As I wrote in my first blog post, research this semester has truly been a learning experience. I learned a lot not only about the subjects we are researching and how our methodology plays into it, but also about how research groups operate, particularly in a college setting.

After fall break, I quickly learned that there was a lot about the research that I didn't even touch on in this first semester, particularly the computational and qualitative aspects. After working with Chloe and Monica on leaching and running the CH-0xx samples, Chloe and I were tasked with running the numbers on as many of these samples as we could. Using a combination of several programs, we gathered and organized the data and eventually exported it to Excel. We then took the activity levels for lead-210 and cesium-137 and corrected these values taking into account radioactive decay, finally getting the numbers we were looking for. At the beginning of the semester, I had no idea how much number-crunching we would be doing, and it was really satisfying to have an actual number to point to and say "that's our data".

It has also been really cool to see that research is a work in progress for everyone. When I first joined the research group, I thought that the methodology was set in stone, but I quickly learned that this methodology was constantly being reviewed and refined through trial and error. I saw this process in action this semester with the introduction of neutralization into the leaching process, which has come with its own set of challenges, but has ultimately proven to be a successful idea.

I look forward to returning next Fall and doing more research!


Tuesday, December 13, 2016

End of Fall Semester Update

Hey ya’ll! Chloe here.

The end of the semester is almost upon us. I hope everybody is getting through reading period and final exams in one piece. Whew, this was a long, fulfilling semester.
The semester began with Gabe, Monica, and I partnered up. We began working through the CH-0XX samples and managed to put a good dent in them through leaching and running. GSA was a big adventure way back in September and I am so grateful that I had the opportunity to go to Denver along with a bunch of other Obie geology majors. Getting to see Obie graduates was also a plus and I know that Monica and I both learned a great deal about how to present a research poster at a conference!
Moving past that, I was able to become more comfortable with the whole leaching process, even while the lab had to deal with acid rain in the fume hoods and the switch to using sodium hydroxide as a base. Using the base in order to neutralize the sample is not difficult and does not add on much more time to the overall leaching process, which is a lucky fix for our acid rain problem. And there is a lovely ~COLOR CHANGE~ in the leachate when adding the base, which is always entertaining. Using pH paper strips, we can just dab a drop of the solution onto the paper to see how acidic or basic it is. We are shooting for a neutral pH, which tends to come out rather greenish on the pH strip and some sort of orange-brown-red color in the beaker full of leachate. When heating up the leachate in order to dry it down, there is a substantial amount of salt that forms on the sides of the beaker. This sneaky salt can simply be scraped off the sides of the beaker back into the leachate, but it is definitely a cool new addition to the whole leaching process!   
Gabe and I also learned how to calculate for decay corrected activity in a variety of CH-0XX samples. This involved learning more about the software on the lab computers and what it is capable of. It was a bit tricky, but with the help of Amanda and one or two of our lab group members, it was easily done. Gabe and I have uploaded our results, which include samples from the CH-0XX group, onto the shared lab group Google drive. J
Well, I’m off to study abroad in ~New Zealand~ next semester so I won’t be posting until next fall. I hope you all have a wonderful spring semester and the leaching process continues to progress smoothly!

Signing off,

The Dirt Lab is getting salty

Its times again for another dirt lab update!

As the semester comes to an end I can definitely say this has been a more eventful experience than last year. As mentioned in previous posts our methodology for readying samples to be run was and is a multi-step process. The samples must first be sieved, then leached and centrifuged, separated into leachate and residue and then dried. A key component we've recently just added is neutralizing the sample using Sodium Hydroxide.

Neutralizing the sample means that we are now evaporating off just water rather than highly acidic HCl. Though, adding this step to the procedure turned out to be quite the undertaking. First, just getting the NaOH took longer than expected. In the down time Hannah, Monica and I (but really it was mostly Hannah and Monica) had the exciting task of locating and preparing samples which had yet to be run. Once the base came in we started to get to work on coming up with a way to get the pH of the solution to as close to 7 as possible. Initially we thought using an indicator would be the best route. We thought wrong. Trying to observe color change in an already colored solution which creates a black complexation as base is added is like trying to thread a needle from space. Its just not going work in a timely or efficient manner. Also considering that the base and acid are different concentrations and that the acid is reacting with carbonates within the sample means that its not the most straightforward process.

Still, we tried to create a method for this madness. Mae Kate, Monica and I started out by adding a fair amount of methyl red to our yellow solution, turning it a dirty orange. We then tried adding half the amount of acids worth of base and saw it turn immediately black and brown. Unsurprisingly, we over shot this delicate process and created a solution that was extremely basic. Which we then corrected by adding a healthy shot of dilute acid (turns out it was 10M instead of 12) which promptly brought it back down an overly acidic pH range of about 2.

After this event Amanda suggested a titration system so I went about setting one up. I found some clamps, a titration beaker and using the methyl red and a slightly expired pH meter kit, was able to correct the first sample to around 7.5 pH.  The end result was an beaker of very nicely separated H2O and sample.

As this way of checking the pH of the samples was extremely tedious, Amanda was able to get us pH papers to test with. The only problem with using those is the possibility of losing some sample to the paper. In order to minimize that we're using a stirring rod and then trying to remove all drops from the rod, so that it is as dry as possible while still being damp from the solution to check acidity levels. 

So thats primarily what we've been up to this semester in the lab. Perfecting this new method of leachate and residue separation. We're still working out the exact numbers to achieve neutrality, right now the easiest way to know when to stop adding base is by a significant color change. We also need to figure out the new composition of samples in regards to the metal content to salt ratio. Previously we were just accounting for Iron and Magnesium in our program calculations, but now that we're precipitating a salt there are new variables to be considered. 

Until next time,