Another week in the books. My main progress this week was assigning specific ages to the literature data I compiled. Some of the data tables I found had ages already assigned to the samples that were taken, but many only had a stratigraphic figure showing a plot of δ13C with both a height axis, a section of the geomagnetic polarity time scale, and — in rare instances — an absolute age axis. Luckily, I was able to use the paleomagnetic information in most cases in conjunction with the 2012 Geologic Time Scale to assign ages to the various sections. I would pinpoint a certain height in the section to the moment when a polarity reversal occurred, which in turn allowed me to match this stratigraphic height to exact age, and by using R, I was able to add these data points to each section and assign ages to the rest of the samples by assuming a constant sedimentation rate. Luckily, we do not care about assigning ages too specifically, since we are looking for trends in the data that occur over longer time scales, but it is still a good skill to learn and one that is of utmost importance in any geologic research.
Compile, compile, compile is the theme for this week. Most of my time has been spent working on the literature compilation, and it’s been a bit tedious to say the least. I’ve been copying data from data table PDFs into Excel spreadsheets, and then into separate files for each location, and while it’s good to be organized, it has been a bit boring.
The good news is I’ve started coding! I knew coming into this project that using R would be an important part of my work, and until a couple weeks ago I had absolutely no idea how to code. Luckily, I found a free introductory course to R programming on Coursera that covered a lot of the basics and I was able to complete most of it before starting. I did a couple of the assignments, feeling very unsure of how much I had actually learned, but it looks like it paid off! I wrote a script that takes all of the separate data sheets and puts all the data into one table and saves it, and I also wrote a script that plots the locations of all of the literature data on a map of the Western United States. It can also filter out the data that is not in our time period of interest and can color code the points on the map by epoch: red points are from the Eocene, blue are from the Oligocene, and white are from the early Miocene. Note that some of these points overlap each other, so we have data from multiple epochs at the same locations.
So far, so good! I’ve been skyping and emailing with Jeremy, since he’s in Switzerland for the summer, and working with Dan and the rest of the group has been great. Looking forward to next week!
Today was a great first day, overall! Calling it a first day is a bit of a stretch, though, since I unknowingly started on this project back in September when I helped Jeremy and Dan (my mentors for the project) collect samples from some paleosols, or fossilized soils, in Wyoming while I was on my Sophomore College trip. I also helped them prepare the samples to be analyzed back in January, before I knew I would be spending the summer working on this project as well. It’s nice to see that the work I put in earlier has paid off, without even knowing at the time that I would continue this project! Plus, there’s no more boring bench work to do.
I spent most of today compiling published paleosol δ13C datasets from existing literature. Our hope is that we will be able to perform calculations of soil respiration using this previously published data, as well as our own samples, so that we have as much information to work with as possible. We need to have the profiles from each specific locality saved in separate files so that we can manipulate them later using scripts that we will write in R. It was a bit tedious, but it will be nice when we finally have a nice, large dataset that we can use to compliment our own sampling. We’ll see how the rest of the week goes!
I’ll be posting about my trials, tribulations, and (hopefully!) successes as I experience the life of academic research for the first time this summer. Information about me and about my research project can be found in the “About” page, if you’re curious for a little bit of background on the project. I just got in to San Fransisco Airport and I’ll be getting started tomorrow! More to come later.