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, November 11, 2014

Update from Hydrostation 55

Hey Sed Heads, 

This is Megan writing (first blog post woohoo!). As Mae Kate mentioned, we are looking at data from hydrostation 55 on the Mekong river (our watershed is on the Tibetan plateau). We are analyzing discharge and sediment data from the hydrostation to determine how these factors change over time; eventually, we can relate this information to changes in land use due to policies allowing intensive industrialization. So far we have mostly done a lot of number crunching, but we are getting close to being able to see some results. We should have some cool graphs to share soon. 

Stay tuned!

Monday, October 27, 2014

First Blog Post \m/

This semester, working with Megan and analyzing the hydrostation data has been really cool! When I first started working in the lab this summer, I felt like I'd never be able to remember everything I needed to know, but now I am feeling confident and super glad that I could even explain a lot to Megan.

<---Here's a picture of Megan running her first sample!

Since we just returned from fall break, I'm excited to get back in the swing of things. As Megan and I finish up analyzing the data for basin 55, it will be interesting to move on to other basins and be able to compare the data between stations. I'm really looking forward to continuing these analyses and seeing what conclusions we can draw.

Monday, May 12, 2014

Basin 49 Results Show Intensive Surface Erosion

Hi all!
This is Dom and Gaby writing. We know it has been a while since we last wrote - It has been a bit of a hectic semester, but we have interesting results to share with all of you!
             With all of our samples thoroughly analyzed by Harbin, we were finally able to start seeing some results for our data. Two weeks ago we used the GIS data compiled by Sarah to calculate upstream area for the basin 49 watersheds.

            As you can see in the map below, our watershed is divided into 3 branches, the west branch (in blue), the east branch (in red), and the main stem in the middle (in green). The watershed where the three branches converge is shaded in yellow.

Last week we began plotting unsupported Pb-210 activity against upstream area, and what we discovered is really spectacular. First, we saw that the main stem had a lot less un-Pb than the tributaries, and that in both cases the amount of un-Pb generally increases with upstream area.

Then, after we separated the results by branches, it turns out that the central river stretch in basin 49 is almost completely stripped of unsupported Pb-210. The graph below shows that most of the Pb-210 that is showing up in main stem river samples is actually from the eastern and western tributaries. 

This data along with the fact that there is no Cs-137 in this basin indicates that there has been intense surface erosion. The results of this graph show that the central river stretch is more eroded than the tributaries.  Our prediction is that this is due to heavier land use along the central branch of the river. In the future, we would like to analyze Google earth images and Landsat data to confirm our predictions.

 This summer Dom will be continuing his work on this project through a Mellon Mays research fellowship. Specifically he will be studying the difference between over bank deposits and in-river, suspended sediment. Gaby has been selected to participate in a Keck project that studies coral reefs in Belize. This research will be the basis of Gaby's geology honor's project. 

It has been great getting to work in this project with our peers and prof. Amanda. We look forward to seeing this project continue to yield interesting data. 

Tuesday, February 25, 2014

Update on lab projects and notes from geomorph lab

Hi all,

This is Gaby writing again, it has been a while since my last post. Since the beginning of the semester, the lab group has run quite a few of the samples that Dom and I are working on. In fact, I think we have less than 10 samples to go, which is pretty exciting. Another good news is that the samples that the team collected in China this January arrived today! We are going to be pretty busy this spring with all the projects.

So, what are the next steps after running the samples for our watershed? Well, after inputting the first wave of data into our excel sheets (excel is incredibly useful!), we need to record the energy peak information to make sure all is going well, and that the channel that the detector has assigned to particular energies is not moving around and giving us misleading results. We want to make sure that we are always measuring the right “spot” or the right energy peak, so that results are more consistent, but also it makes it easier when subtracting background noise from the raw data. The step after this one would be to learn how to use a software called Angle, which helps us calculate further corrections that regard the volume and shape of the sample (more on this when we start using it).

Since I’m taking the geomorphology class this semester, there have been a lot of interesting connections that have occurred these past weeks between our work at lab and the class. One of the most basic but important concepts that I had an interesting time working through is that soils are not just simply deposited in sedimentary layers. This might seem pretty basic, but in geology there is strong emphasis on the idea that newer stuff deposits on top and that things are in chronological layers, with the deeper stuff at the bottom.

Soils do not fit this model very well. In fact, soils can be easily deposited or eroded, and they also can form “from the bottom” of the soil horizon, adding new soil that won’t necessarily receive radionuclides if it is deep enough. Besides all this ways soils can be moved around, there are also processes of bioturbation and other types of mixing that also conflict with the idea of chronological deposition. Just the fact that the “soils” are on top of each other is not an assurance about how the landscape formed. Like I said before, this might seem pretty basic, but realizing this did shatter a lot of my assumptions about landscapes. From now on I’ll be having a more critical mind on both the work that I do and the papers we read for lab.

Looking forward more connections and findings this spring semester, write to you soon,


Monday, February 17, 2014

Summary of “Sediment accumulation determined with Pb-210 geochronology for Strickland River flood Plains, Papua New Guinea”

In this 2005 paper, Rolf Aalto and William Dietrich give a fascinating introduction to their fieldwork on the Strickland River flood plains in Papua New Guinea. This paper focuses on the timing and rate of sediment accumulation in the river. Most of the paper describes the Pb-210 geochronology methods they use to date sediment accumulation. The experiment involves a dating approach this team of scientists have used more than once called CIRCAUS (constant initial river-reach clay activity). This method starts by taking 8-20 measurements of clay-normalized excess Pb-210 activity and many depths in each core .
Aalto and Dietrich use clay normalized pb-210 activity because clay preferentially absorbs mobile Pb-210. They are then able to deduce how much of the pb-210 activity is caused by meteoric rain out and soil radon decay. This allows them to exclusively use mobile pb-210 to measure the rate and timing of sediment accumulation. At the time this paper was written, the two writers had only analyzed 36 of about 200 cores taken from diverse locations in the floodplains. From the 36 cores the analyzed, the authors saw that most of the floodplain has received little to no accumulation over the past 100 years. This is most clearly represented in figure 3, which shows two graphs of DPM/G as a function of Depth (cm) and % Abundance (clay and sand ).
 Although one chart is for a terrace well above the floodplain and one is for a core taken from the flood plain, neither shows significant sediment accumulation. In the future, Aalto and Dietrich plan to expand upon their preliminary findings with data from more cores and a better understanding of the way that floods affect their geochronology procedures .

Tuesday, February 4, 2014

Hotel standards and driving in China

I promised this post ages ago and have now been back in the US for over a week. Sorry.


Nearly 10 years ago, during my first year in graduate school, my mom and I went on a trip for her 50th birthday. We went to Kunming, Dali, Lijiang, and Tiger Leaping Gorge, all in Yunnan, China. It was my first trip to Yunnan. I told Mom she could only go with me if she promised to travel "my way". I had fantasized about backpacking around China and meeting cool people and I didn't want to be hampered by a mother insisting on staying in fancy hotels. So we each had a small backpack (you can see pictures of mine in our field work photos from January - it's the blue and black one) and took a flight from Shenzhen airport to Kunming. We stayed in a youth hostel and bought train tickets (only soft sleepers available, darn it). We bicycled around Kunming. We stayed in hotels where beds cost 10 RMB (about $1.25 at the time) and I refused to upgrade to rooms with beds for 15 RMB. I wouldn't let Mom hire a horse to carry her or her stuff on the hike, even though I now realize she was suffering from altitude sickness... we were at elevations close to 10,000 ft.

On this trip to China, Yue found us the fanciest hotel she could in most towns we stayed in (not Dali or Kunming, but everywhere else). We stayed in hotels with breakfast buffets that sometimes even had western food like cereal, a waffle bar, and an omelet bar. One hotel had rose petals in the toilet and a bathtub in the bathroom. I think hotels averaged about 250 RMB (about $45) a room. We would never dream of staying in rooms with shared bathrooms or in dorms.

How my standards have changed!

Another note I promised:

It's amazing how quickly I remember how to drive in China. Honking on every turn, passing whenever the corner is less blind, slamming on brakes when you see traffic cameras that will catch you speeding (but I did get a speeding ticket and a parking ticket anyway). I always worry that I'll forget how to drive in the US when I get back, but I seem to have done ok. The places we were driving in Yunnan, especially the main east-west highway from Kunming towards the Myanmar border, seem to be particularly prone to accidents, so there were graphic signs on the road about what happens at different driving speeds. Burned and crashed cars were on pedestals on the side of the road as a warning. One had inflatable feet and legs dangling out of it. I only had two close calls, one of them on my 3rd to last day of driving. But they still scare me. The last thing I need is to have me and possibly a student in a hospital in rural Yunnan. I have to admit that towards the end of my nearly 6000 km of driving (in under 3 weeks), I was starting to get a little wigged out. Colby needs a mom and the new baby needs to be born and to have a mom. I was happy to return the rental car. And I'm happy to report that I took a few cab rides in Chengdu and Shanghai and survived them fine, and, more importantly, I remembered that one can't pass on blind corners in the US and you shouldn't honk on every corner or each time you pass.

Wednesday, January 22, 2014


The blue pins are all our sample points. Lots of driving over the past 3 weeks. I am now in Chengdu. I had lunch with Renjuan (she was in Oberlin for part of the fall) and now am off to see other friends.

Tuesday, January 21, 2014

Tying up loose ends

I am sitting in the sun in Dali, Yunnan watching people wash our really dirty car. Mainly I need them to remove the green paint from where our number had an encounter with a bus bumper in a gas station. Inside and out the cleaning will cost 30 rmb ($4.50ish). I just mailed our 15 boxes (380) kg of samples to dongguan, where they will be put on a truck, taken across the border to hong kong and then air freighted to Cleveland. Tonight I drive to kunming by myself. Yue left this morning for shanghai and Adrian and Veronica are already home.

I hope to give you all a short description of my changing hotel tastes over the years and driving in rural yunnan. Maybe from the hotel tonight.


Sunday, January 19, 2014

Warming up on a cold morning

We stopped for yak butter tea (酥油茶) on our way to our first site of the day. Salty but a nice warm treat.

Wednesday, January 15, 2014

Packing samples

We don't have enough shipping boxes yet but decided to take advantage of getting done early last night (8:30 pm) to organize samples and prep them for shipping. We didn't want to do this when closer to the Myanmar border in case it looked like drugs or some other suspicious contraband.


Tuesday, January 14, 2014


Bad photo, but... The red arched things in the middle of the picture are the Burma-China border crossing. Veronica's phone thinks it is in Burma.

Saturday, January 11, 2014

Greetings from the shore (Gaby's intro)


My name is Gaby, I’m one of the people participating in Prof. Amanda’s lab (I use she/her/hers or they/them/theirs). I’m a Geology and Environmental Studies double major with a soft spot for literature. At the lab I team up with Dom preparing samples from our watershed to be run in Harbin, the germanium detector (Harbin is another member of team!). This coming semester might have some exciting results, as we will be able to see the analysis of our watershed samples. We also have weekly lab group lunches with delicious homemade bread, PBJ and apples (which in Ohio are very good). The lunches are a good time to catch up to what everyone in the lab is up to research wise and also about their activities outside of class. 

            I’m spending this winter term as an intern at the Woods Hole Oceanographic Institute. Interestingly, the lab I’m working with also uses two germanium detectors. This project looks at sediment cores to learn about hurricane cycles in New England, and also test their storm surge model. They also use radionuclides to date the sediment, although the samples are handled much differently. We also have an one-hour class in the morning about the different sub fields of oceanography. It is overwhelming to consider all the factors that come to play in the ocean, and all the same more interesting.

            Woods Hole is a lovely town, the people have been warm, and the winter not so harsh in contrast with most of the country this January. I was born and raised in Venezuela, mostly in a town by the ocean, so being able to take walks on the beach every day is lovely, cold weather and all. It was also the first time that I've ever seen snow on a shore! Of course, I ended up knee deep exploring around and collecting cool rocks and sea shells. 

Although the snowstorm was intimidating, the calm after it brought a beautiful landscape. 

But going back to Oberlin, this is Carnegie, the building that hosts the geo department and our lab. As you walk up the stairs, shelves full of rock specimens appear, which is the school's geology museum (the department is cozily nestled on the third and fourth floors). 

This is a picture of some of the shelves and geo majors taking a picture for the resource conservation team's recycling campaign. I'm on the far left holding a soil sample for Harbin, and Adrian (whom you've already met) is holding a large sieve.

To the lab team in China: Stay strong! Best of luck on your travels.
To the lab team back in Oberlin: Stay warm, and enjoy working around in the lab.
To the lab team around the world: See you all soon!


A typical day in Yunnan

A typical day in the field involves more than six hours of driving from places to places trying to find the river we're sampling at. And every now and then there will be crappy road conditions like this: 
This picture was taken on our drive along the Vietnam border on a narrow mountain road that is undergoing construction at multiple segments all at the same time. (Detailed stories will follow)

Or sometimes the road is like this one:
This picture was taken after we drove up a relatively steep dirt road (not shown in this picture). We got stuck in the middle of the road the first time and had to back down to the bottom of the track and power through it again. Look at all the dirt we stirred up!!

Although we sometimes drive on new and wide highway roads, most of the time we have to deal with the sucky road conditions. Yet we always survive simply by..... SNACKING!
Local people sell fruits along major county roads and we've gotten bananas, tiny oranges  (沙糖桔), pickled green mango salad, and sugar haws. So far we've also finished a whole big jar of peanut butter and eight backs of crackers as well :) Amanda and I each had more than ten tiny oranges in three hours one day. It's also probably the only things so far that the four of us unanimously said "oh yummy!" to. 

Oh and we do actually take samples (and not just driving and snacking)
We have a ton of field gear that we bring to each sampling site including waders, sieves, cameras, field notebook and lots of ziplock bags. (Detailed story will follow) some of our sampling sites are really pretty. Like this one! We got to the Mekong just around sunset and I was stunned by the beautiful scene and pretty rocks. I took this picture before we started digging up the river sand and when we were done the sun has completely set.