I thought I'd share a brief synopsis of the research project I did this semester.
Here is a map of the area I studied:
There was a master's student who graduated last year who did an extensive study of the chemistry of the soil in this region (at the spot marked "Sun's study site"). The results of the Strontium analysis were very interesting. Strontium has a few different isotopes (same element, but with different weights due to different number of neutrons), and one of the ways to determine the ages (and other characteristics) of rocks is to find out how many of each isotope there are in the rocks. So they take Strontium-87 and compare it to Strontium-86. In this area, you would expect the ratio of 87Sr to 86Sr to be low because it is in the coastal plain and the rocks are relatively young. But in Sun's project, the 87Sr/86Sr ratio was higher than expected--more comparable to the older rocks to the west. So my adviser came up with the idea of having me collect water samples from the area and then find the 87Sr/86/Sr ratios for all of those samples so we could compare the results and get some ideas for what's going on.
So I collected the water samples and separated the Strontium out, which I blogged about before, and then I put the Strontium on filaments to run in a mass spectrometer to measure the amounts of the different Sr isotopes. The results were that the four samples on the west and the three samples on the northeast had 87Sr/86Sr ratios that were about what you would expect--similar to the seawater and groundwater of the area. But interestingly, the three samples within the national forest (CF-C, GL, and HC) that are near Sun's Study site all had high ratios, although not as high as the ratios for the soil she studied. So now the question is where this area is getting 87Sr from, and there are a lot of possibilities.
The main thing I learned is that I still don't know very much. But I do feel excited that the numbers I got from the mass spectrometry make sense and have some meaning. I'm guessing I will be studying this some more next semester.
So I collected the water samples and separated the Strontium out, which I blogged about before, and then I put the Strontium on filaments to run in a mass spectrometer to measure the amounts of the different Sr isotopes. The results were that the four samples on the west and the three samples on the northeast had 87Sr/86Sr ratios that were about what you would expect--similar to the seawater and groundwater of the area. But interestingly, the three samples within the national forest (CF-C, GL, and HC) that are near Sun's Study site all had high ratios, although not as high as the ratios for the soil she studied. So now the question is where this area is getting 87Sr from, and there are a lot of possibilities.
The main thing I learned is that I still don't know very much. But I do feel excited that the numbers I got from the mass spectrometry make sense and have some meaning. I'm guessing I will be studying this some more next semester.
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