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!

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

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! 

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! 

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! 

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   

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!!

Dominica, Post Hurricane Maria

Hi All,

It has been a very adventurous, very busy, and very exciting month for me. My name is Melinda and I’m an undergraduate from the University of Vermont where I work in the Cosmogenic Nuclide Laboratory. How did I end up in Dominica? Here’s a little story:

In the fall semester, I was working on improving the methodology of extracting Beryllium-10 from olivine. Acid dissolution had some complications, so my research advisor, Paul Bierman, suggested flux fusion. However, we flux in a batch of 16 (where one is a blank), so 14 Dominica samples (pre-Maria) were added to this batch.

Soon after the world entered 2018, I received this fabulous opportunity to collect samples at the rivers in Dominica for post-Hurricane Maria data (thank you Amanda and Paul!). Fun fact: I love looking at extreme weather events and have a small dream to chase storms like the tornado chasers in the movie, Twister. In this two-week notice I had to prep for my first trip ever out of the country. I started my journey solo to Barbados at 5:30am. Waiting for the Oberlin fellows, I was able to see sea turtles, crystal blue waters, and be on an insane taxi ride (I’m originally from NYC so these taxis were a new rush). Only at almost midnight is when I met the other 3/4^ths of the field team – Amanda, Marcus, and Ely (who I have never met until then). The next day, we headed to Dominica.

“Wow” is the one word I decided on to describe the good, the bad, and the ugly. In the hot, humid 80-degree weather with random rainstorms (which we were fortunately in the car or sheltered for the most part) we sieved at about 7-10 sample locations per day. How much I wished I saw pre-hurricane Dominica instead of having to just hear about the vast differences in landscape! There were many landslides and many rivers we sampled at carved a new channel and/or increased in discharge. The views were great, roads were cleared of debris (even though we got lost a few times), the rivers kept us cool, and chicken never failed us as a food.

This is the place we stayed at where we had to walk through a river .

In the Morne Trois Pitons National Park, this trail was covered by fallen trees. However, they have made great progress in cleaning up.

Emerald Pool in the national park.

During the last night of late night packing and organizing, I took a small portion of the samples that I needed – the ones that matched the sample locations and grain sizes of the pre-hurricane samples I used. Once I returned to Vermont, I went straight to work on extracting meteoric Be-10 in 2 weeks (in order for my samples to be analyzed on time). Fortunately, I don’t need very much of each sample, but I had to dry, sieve a few samples, and powder everything before I could flux. Between classes and work, I was (and still am) in the lab working on extracting Be-10 and drying them to pellets. Very soon, my samples pre- and post- Maria will be sent to the accelerator mass spectrometer in Livermore, California to be analyzed.

It has been a whirlwind from initially working with olivine to now working with Dominica samples, which I will be incorporating into my honors thesis. The beryllium isotope data I will receive will help understand sediment movement and erosion rates on Dominica. It will also be super exciting to compare the isotopes pre- and post-Maria!

One more fun fact: sieves caused a lot of trouble through security in my carry-on than the sand samples.

A sneak peak of the meteoric lab and the flux fusion method used. The crucibles hold the sample and the addition of KHF2 and NaSO4 lower the melting point such that the sample can be fluxed.

Here’s to great opportunities and meeting new people~

Melinda

Dominica Round 2

Hello Everyone,

Marcus here, and this will be my recounting of another eventful winter-term project. As mentioned in Ely’s post, we went back to Dominica for post hurricane Maria sampling. In preparation for the trip I worked on mapping any visible landslides from satellite imagery available after the storm. I was able to spot well over 500 in the regions of the island that weren’t covered in clouds. Im sure if I had clearer pictures I’d be able to find another 500. The good news was that they seemed to be mostly small, not affecting huge swaths of land.  The bad news was that even though landslides didn’t move that much earth, the island still was catastrophically affected. As I was searching for anywhere which could’ve been hit by a mass-wasting event I noticed large areas of bare and downed trees. I didn’t really know what to make of that, but I figured it was important and marked it down anyway.

Dark brown regions indicate lots of downed/bare trees while the red/black dots & points are landslides. Much of the eastern portion of the island satellite imagery was blocked by clouds.

Going back was truly a wild experience from start to finish, especially because we didn’t know if it was happening until December, and even still, nothing was set in stone until almost two weeks before we left! Obviously, its very hard to complain about leaving the oh-so-warm Ohio January for an island in the Caribbean, but this wasn’t just a vacation. We were working. Hard. The trip started with us leaving for the Cleveland airport at 4:30AM on Thursday, Jan 18^th, and ended with us returning at midnight, Friday, Jan 26^th. There was tons to do everyday, the first three days were dedicated to sampling. We had 31 unique locations to go to all across the island, and from each we wanted around 3-4kg's of sand. Our final day was spent organizing the mess and preparing it for the four flights home. Have you ever checked 350lbs worth of '''soil''' through three different customs offices? Its an exciting time for all parties involved.

The trip itself was very bittersweet. On one hand, it was amazing to be able to go back—this information is really unique in that we rarely ever have the before data for serious natural disasters. On the other hand, just seeing what the storm did to the island was breath-taking in every sense of the word.

Before                                                                          After

Both sets of photos are from one of the main natural attractions on the island, Trafalgar falls. I really can’t describe what being there in person was like after being there over the summer, it was surreal. I’d seen pictures right after the storm on Facebook, but the gravity of the situation really just isn't the same unless you’re there.

After the storm, 2018 on the left - Before the storm, 2017 on the right. (its wrong, i know, i know)

                                              

This is another sample site, the pictures are harder to compare but that’s largely because the shape of the channel evolved so much after the storm. As seen in the before picture, the water is very shallow and easily navigable. To go to that same spot in the after picture would’ve put me in over my head.

And scenes like this were common in most of the streams we sampled. It was a complete 180 from what we observed over the summer. Being there in person really put into perspective what I was seeing from the satellite imagery, and the magnitude of the hurricane. These trees didn't look anything like those that I saw over the summer, instead they were like something out of Horton Hears a Who.

And then there was the toll on buildings..

The location where the KECK group stayed at over the summer.

But overall, it was a successful trip, it was and still is one of the most beautiful places I’ve ever been. We stayed at a variety of places across the island and had the luxury of waking up to views like these.

Which makes it that much easier to spend the whole day collecting sand. In total, we wrangled almost 400lbs of wet sediment from 20+ different rivers and streams across the island. We are hoping to use the gammaspec in the lab to understand how these water systems are sourcing material across the island. Now that we have two sets of data, we are also trying to understand what a massive storm like Hurricane Maria does to erosion in general on the island. This specific question will be one of the primary focuses of my honors project. I think another big portion will be a comparative analysis of before-and-after’s for the locations we sampled. As I showed in those initial pictures, so much has changed.

Since we’ve been back Ely and I have had the enormous task of preparing the samples to be analyzed. That means moving every particle of sand from the bag we packed it in into another bag to be autoclaved (a fancy way of sterilizing it) and then dried again. Luckily, we don’t need to dry all of it, just enough for us to keep here, and we can ship the rest of the wet stuff to Melinda at the University of Vermont. We also had some issues with sample collection in the field that we figured we could take care in the lab, so there’s been a fair amount of sieving going on in the Oberlin College Geology department. It was such a fun activity to do for 3 straight days in Dominica that I’m glad we get to do it here too!!! In all honesty, it wasn’t bad; it’s a pretty monotonous task but it goes by fairly quickly.  Now that we’ve got what we need all of the samples have been repacked and will soon be en route to Vermont. The last thing to do is tidy up the lab before everyone else arrives and sees the mess Ely and I have made of it.

As the data is time locked behind 24-hr run cycles through our gamma-spectrometer it’ll be somewhat slow going at first, but I hope to see some initial results within the next couple weeks. I’d like to try and post updates to this blog more consistently in the coming two semesters, as a way to track my progress as well as keeping me on track, with Amanda’s approval of course.

I’ve also been working with Jason Williams and his STEM based initiative, Get With the Program, more and more recently, but as this post is already so long I’ll post some updates for that in a little while.

Until next time,

Marcus

Also just a fun picture of the trail to one of our bed-n-breakfast locations. We had to cross a knee-deep river by headlamp light in the pitch black. It wasn't too dangerous or anything, there was a safety rope if we needed it.

Winter Term Recap

Hi, This is Ely,

I wrote on the blog earlier this fall, talking about the beginning of my journey as a research assistant in the geomorph lab. I’ve been working with Marcus on his Dominica KECK research project. Over the summer, Marcus was able to travel to Dominica in order to collect river sediment samples. Since the start of fall, I’ve been helping Marcus with running these samples in HARBIN and the XRD.

After Hurricane Maria hit the Caribbean, Amanda noticed that we had the rare opportunity to collect post-hurricane sediment samples from the same locations that they were collected in the summer, before the hurricane. We set a date to head back to the island during winter-term.

Before leaving for Dominica, I spent time looking into software that would better allow us to identify the composition of our samples from the data the XRD provided. Up until now, we’ve been trying to do this using d-spacing charts and sifting through extensive lists of elements and minerals hoping for a match. However, the software we are using should supposedly do this for us in a matter of seconds. The programs we are using are Match! 3 and MAUD. Match! 3 is what we use to identify likely minerals within our samples. It looks through an index of thousands of known minerals and their XRD data sets, trying to fit each one to ours. One issue is that our samples are mixtures of many different minerals, and Match! 3 tries to fit a single mineral to our entire XRD data set. We can combat this by taking many minerals off of Match! 3’s candidate list, as well as data for minerals that make sense with the geological history of Dominica. We throw all of these into MAUD, which makes a custom diffractogram using Rietfveld refinement. It’s really a process of trial and error, adding in likely minerals, and removing them if MAUD can fit them onto our sample data.

Using Match! 3 to analyse DM-6.

In order to take a break from working in the lab, Monica Dix (a fellow lab mate) and I toured the perimeter of Lake Erie. We headed east to Detroit, the through Windsor, ON, and drove all the way to Niagara Falls before heading back to Oberlin. Along the way, we tried stopping at as many tourist spots as we could, including a Lake Erie history museum in Detroit, lighthouses, the Great Lakes history museum in Cleveland, and of course, Niagara falls. This was a great road trip, as I was able to see parts of the lake that I never had before, and despite it being winter, the views were spectacular.

Before too long, it was time to leave for Dominica. Amanda, Marcus and I were joined by Malinda Quock from UVM. Day 1 on the island consisted mainly of flying in from Barbados and searching for our Airbnb. The home we were staying at had a beautiful view of Dominica’s capital, Roseau. After settling in, we were able to get in one sample site.

View over Roseau,

 A mother-son pair of dogs that hung out on the property we were staying at,

 Image 3: the view from our first sample site

.

The following days were spent rushing from sample to sample trying to get as many in as possible before sunset. Marcus and Amanda provided interesting commentary for each site, remembering what they looked like during the summer, prior to the damage inflicted by the hurricane.

Caption: One of our sites was clogged by woody debris most likely as the result of Hurricane Maria.

                                                         Caption: One of our more beautiful sites was Trafalgar Falls

When heading back home, we had to connect to Fort Lauderdale through Barbados, which meant a day full of crystalline beaches. Our Airbnb host, John, was very hospitable while we stayed with him and gave us a tour of Barbados. We had some delicious coconuts, and I swam in an ocean for the first time.

Now that we’re back on campus, Marcus and I have been sorting and sieving the samples we didn’t quite get to while out in the field. We are preparing some for leaching, and some will be shipped to Malinda at UVM.

As for the future, I will unfortunately be unable to continue working with Marcus as he begins working on his honors project. I will instead be working with Josh XRDing China samples Amanda had collected a few years ago. I hope to increase my abilities in understanding how to interpret XRD data, as I am dead set on become fluent when it comes using XRD-analysis software.

I am truly grateful for the opportunity to go to the Caribbean and assist Marcus with his KECK research. I look forward to what adventures will open up for me in the future.

Thanks for reading!

Ely