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.

Tuesday, December 11, 2018

Ely and Amelia take on GSA and field work!

Marcus and Ely presenting on Dominica. 
Monica and Amelia presenting on Plum Creek Research.

Last time on the blog, we (Ely and Amelia) had just been to UVM working on XRF data. We then incorporated this data for our collaborative GSA posters! The conference was an exciting experience and we learned a lot from talking to other people in the field and attending sessions. We networked with Amanda's colleagues and took in the exhibits. We also had a great time riding electric scooters from the hotel to the conference center.

We have also been busy at work in the lab.  We moved machine lab spaces and have been preparing to have 4 gamma spectrometers as opposed to 1 soon. We also have been doing lots of housekeeping as we will be doing a larger move in the summer. This means lots of sorting, cleaning and getting samples ready. We also autoclaved. An autoclave is essentially a large steam bath that reaches temperatures that sterilize the machine's contents. We use this on our samples to ensure no creepy crawlies made it back from the field.

Ely will be away in London next semester and Amelia will be working in the lab again next semester!

Thursday, December 6, 2018

China Project Update

Hey it’s Sophie, Alex, and Paige!

Sophie and Alex would like to welcome our new member of the lab Paige Monyak. She is a first year from Ohio interested in geology and environmental studies. She joined the geomorphology lab at the beginning of her first semester here at Oberlin and has been working on the China project. Over the 2019 Winter Term, she will be traveling to the Sichuan Province of China with a group of students and staff to visit various nature reserves and to have a more in depth understanding of the China project.

Sophie and Alex recently went to the Geological Society of America meeting in Indianapolis to present their research for the China project. It was so much fun to meet other people in the field, learn more about geomorphology, and contribute to a larger conversation surrounding the use of fallout radionuclides.

Sophie and Alex presenting at GSA

Sophie and Alex have been showing Paige the ins and outs of the lab. This semester, the sediment samples were wet sieved to separate them into different grain fractions. The separated sediment (<63um) will be used to begin the leaching process! By using these smaller grain sizes, the grain size dependencies of 137Cs and 210Pb can be eliminated. The next steps will be to run the sieved samples in a detector, create a leachate, then rerun the leached samples in a detector.

Next semester, Alex and Sophie will be studying abroad in New Zealand and Bolivia respectively. Paige and an additional lab member will be taking over! We trust our grains with her :)

Sophie, Alex, and Paige in the lab

Tuesday, October 23, 2018

Ely and Amelia are working on prepping samples for the XRF!

Hello from Ely and Amelia!

We’ve been hard at work getting samples ready for the XRF machine at UVM! We have been focused on the Puerto Rico and Dominica samples in the lab.

This meant that we spend a lot of time in the lab getting samples prepared. For me (Amelia), it was the first time I had worked with acid on leaching samples in the lab. Samples that had already been collected are brought to the lab and then the grain coating is separated from the grain using HCl. The grain coating of the grain has many of the FRN’s we are looking for, so seperating from the grain is an important first step. Then, due to the acid used in the process, the sample, both the grain coating and the grain, must be neutralized so it doesn’t destroy our brand new oven. This involved rinsing the grains completely with water to remove the acid and titration the acid/grain coating mixture with a base, NaOH. I found the process to be a lot of trial and error but am getting the hang of it! The samples were then dried in the oven and transferred to containers to be run!
This is a sample from a Puerto Rico watershed that has just been leached! The grain coating is the yellow sludge part!

Here is our oven (named Quincy) full of drying samples. The white part on the beakers is neutralized salt from the titration and the the darker part is the grain coating. 

While at UVM, we have been hard at working running samples through a machine called the XRF. Mae Kate, an ObieGeomorph alum, has been training us to prep and analyze the samples that we are planning on running. Preparing our samples to be run involves transferring them into small plastic containers. This can be a tedious process, as the openings on these containers are small, and our leachates are often very tough to break up. Thankfully, only a small amount (2-3 grams) of each sample is needed to obtain all the info we need. The XRF can give us the element composition of the samples, for example, we can find out that a particular samples contains 5% Fe. We can use this data to learn more about sediment transport and whether a sample has a typical composition.
The samples are being transferred into smaller containers for the XRF by Monica (left) and Amelia (right)! Monica is also at UVM running the XRF! 

Here is Ely running the XRF machine! 

Monday, May 14, 2018

GIS; a learning process

This semester I have been doing some GIS work for the Cuba project. One step in the project is to find all the gauge stations in Cuba by using different maps, satellite images and tables/graphs from papers. My first step was to download and order some of the declassified satellite images from USGS. With these as well as some maps that Mae Kate found in the UVM digital map archive, I was able to use a tool called rubber-sheeting to create more comprehensive and complete maps. To rubber sheet I took a shapefile of Cuba which included roads and used it as reference to geo-reference the road maps from UVM. I did a similar process with the declass images. However, they unfortunately did not cover as much surface area as was projected on the USGS site. I also used these images to start creating land cover data for the satellite images, which involves creating polygons for a group of pixels on the images and classifying them as either urban, pasture, forest or water. I wanted to create a specific LULC system but the images were not clear enough to distinguish between for example, residential and commercial infrastructure.
This semester was truly an exploration in GIS (but this time, without a detailed description of the steps and process to create a certain map, which is what I had last semester in Amanda's class). I learned the wonders of Google, GIS forums and earned an even greater appreciation for the portfolio I made for Amanda's class (and my mom for the many times I FaceTimed her for advice). I'm now graduating but I hope to continue to do GIS work at some point in the future! 

Sunday, May 13, 2018

Amelia Works on Plum Creek Samples

Hello, this is Amelia Lewis! This was my first semester in the lab and I worked with Monica Dix on the Plum Creek Study. This study is looking at seasonable variability in the short-lived radionucleotides of the sediment in Plum Creek in Oberlin, OH by sampling 4 sites along Plum Creek with different upstream land uses. 

I learned a lot about lab techniques and sampling techniques this semester. I went on sampling rounds and collected sediment from the channel bed. I also learned how to process the samples. I worked on wet sieving to separate the clay from the rest of the sample, as the clay has the largest surface area and is therefore what is tested. I learned how to take parameters of the samples and run Harbin, the machine that tests for the radionucleotides. The Plum Creek study ended this spring, so the next step is to get all the samples run and start sorting through the data. 

Here is one of the sites along Plum Creek that was sampled. 
This is another sample site along Plum Creek.

In the class also taught by Amanda Schmidt, Earth Surface Processes, I am working on continuing an investigation of Plum Creek. My final project for the class that I am working on with another research student, Sophie Maffie is re-surveying the locations for the Plum Creek study that were taken Spring 2017 and looking for changes between the locations over time. We also put in re-bar into the channel banks and the thalweg, or the fastest moving part of the river, in order to test if the river is incising and will measure the rates in the future. This data combined with the Plum Creek sediment samples will provide a good idea of what sorts of processes are occurring in this area. 

I’ve really enjoyed working in the lab this semester and am excited to continue next year! 

Thanks to everyone in the lab for a great semester! 

Friday, May 11, 2018

Hi Everybody!
This is Ely Bordt and Josh Biales! This semester our objective was to determine mineral compositions of Sichuan Basin clay samples collected in 2015. We are hoping to see if these minerals are consistent with those found in prehistoric lake beds. In order to determine these compositions, we performed X-Ray Diffraction Analysis on 10 samples to obtain diffractograms of various peaks that may provide insight as to what the mineral makeup of these clays are.

Having ran our samples in the XRD which produces these diffractograms, we then had to somehow decipher what compositions the peaks indicate. To do this, we analysed each diffractogram using PDXL, a software that produces a list of prospective minerals that our clays could contain, ranking them from best match to worst. An example of a diffractogram that was run through PDXL can be seen in figure 1.

Figure 1: A diffractogram for sample YJ-011 that was analysed using PDXL.
The top 3 best-fit minerals are listed in the right-middle box.
PDXL produces a list of  the best fit minerals that is likely to make up our sample: SiO2 (quartz low), LiD (Lithium Deuteride), and Fe6Si4O10(OH)8 (Greenalite). Because we cannot say that PDXL is 100% accurate, we run the diffractogram again using another program called Match!* 3. By running the plot through this second program, we can double check if PDXL is producing accurate results. The output from our Match!* 3 analysis can be seen in figure 2. Notice that the top best fit mineral is once again SiO2 (quartz low).

Figure 2 shows the best-fit minerals for YJ-011.
The percent match is displayed on the right of the bottom panel in green. 
Having run our sample through both PDXL and Match!* 3, we can use the Open Crystallography Database to obtain .CIF files for our best fit mineral. CIF files are ideal diffractograms for pure minerals. We can search for our minerals (for example, quartz low) in the Open Crystallography Database, obtain its CIF, and overlay it on top of our sample's diffractogram. If the minerals produced by PDXL and Match!* 3 are in fact in our clay, then their CIF should lie neatly on top of our diffractogram.

The program used to overlay our minerals' CIFs is MAUD. MAUD is able to take our minerals' diffractograms, adjust them on top of our own sample, and depending on how much adjustment was needed, produce percent compositions for our sample. After importing the CIFs for Quartz Low, Lithium Deuteride, and Greenerite, the final diffractogram can be seen in figure 3.

Figure 3 shows our 3 best fit minerals (red peaks) overlaid on top
of our sample (black peaks).  
The CIFs matched up amazingly well for YJ-011, and for each of our other 9 samples. For YJ-011 in particular, the percent compositions as indicated by MAUD are 16.7% Quartz Low, 82% Lithium Deuteride, and 0.55% Greenerite. 

Of course, these values are not completely accurate. Since we are dealing with clays, there are likely  immeasurable amounts of trace minerals among the material. However, based on the consistency between our samples, getting some amount of Quartz low and Lithium Deuteride for most if not all of them, we are confident that we are headed in the right direction in terms of determining the compositions of our clays.

At this point, we still need to take our findings and cross reference them with minerals that are commonly found in prehistoric lakes.

Over the course of the semester, we learned a great deal about how to obtain data from the XRD and analyze it using various software. Perhaps we could take what we learned about the analyze portion, and apply this to the Dominica samples that we tried XRDing in the fall.

We can proudly say that we are leaving this semester with new-found skills in compositional analysis.

Thanks and happy geomorphologing!
Ely and Josh   

Wednesday, May 9, 2018

Smaff and Syd take the Geo Chem Lab

Hi all,

Sydney Garvis here, with my lab partner Sophie Maffie! It is my second semester in the lab and Sophie's first!
This was a semester of organization, an underrated aspect of lab work. We consolidated a lot of different spreadsheets into one, a full data collection and inventory spreadsheet! Riveting stuff, really.

Sophie was an eager student and picked up all our lab procedures quickly. We were able to leach and neutralize several samples that were collected in 2013, during Amanda's first field season for this project in China. (The Harlem Shake viral video trend was at its peak in 2013!) We learned the art of wet sieving from other lab mates, and have many CH samples ready to be processed.

We've learned a lot this semester by reading literature and discussing papers that have been published about the type of lab work we're doing. I also have been mentoring Sophie to set her up for a productive and successful season working in the lab over the summer!

I've really enjoyed my time working in the lab, with Gabe and Gabriel last semester, and "Smaff" this semester. I'll be graduating at the end of May and for the next two years I'll be in Indonesia teaching English through the Shansi fellowship.

Sophie and Syd in the lab with our bags of dirt!!