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Geology major Sean Murphy ’11 (Stoughton, Mass.) is exploring changing wind speed on the Atlantic Ocean over the past five million years as an EXCEL Scholar with Kira Lawrence, assistant professor of geology and environmental geosciences.
Professor Lawrence and I are working with ocean sediment in an attempt to learn more about the climatic conditions of the planet over the past five million years. Professor Lawrence is working with another student to amass data that track the temperature of the ocean surface. With this project, however, we are interested in learning about wind strength over the North Atlantic Ocean and how it has changed during the past two to four million years.
To do this, I analyze the silica (sand) content of ocean mud using infrared spectroscopy. This can be used to learn about wind strength because the type of silica we look at can only be delivered to the deep ocean by wind. It follows that if there is relatively more wind-blown silica in the mud, then stronger winds must have been dominant during that interval of time.
Before I can analyze the mud, however, I use multiple chemical reactions to eliminate the non-silica components of the mud. It is important that nothing but terrigenous (land-based) silica remains in the sample before proceeding. After mixing that silica with a salt, I am able to produce a very thin pellet and run infrared light through it. The machine which produces the light also gives us a curve from which we can obtain the percent of silica in the original sample. We hope to see a dramatic change in silica content around the same time as a similar study found there to be one, around 3.7 million years ago.
I am very interested in planetary sciences, so this opportunity fits me very well. Professor Lawrence, her other EXCEL student, and I will be visiting Brown University this summer to see their planetary sciences department, which is another opportunity I am fortunate to experience. I have just recently started thinking about graduate school, so the timing of this visit is perfect. As my adviser, Professor Lawrence knows what aspects of the geological sciences I am interested in and has indicated that there are multiple departments and professors at Brown that may suit me well. Being able to continue our hands-on laboratory-based approach at Brown will hopefully be a good preview to what grad school will really be like.
I have been working with Professor Lawrence ever since I came to Lafayette. She taught my first geology course, Earth’s Climate: Past, Present, and Future, during my first semester. By the end of that class, I knew I wanted to be a geology major and she soon became my adviser. I have since taken a Values and Science/Technology class with her on climate change, and I plan on taking one more class with her during my senior year.