Many of us might think of classwork and research as two separate entities. Here at Princeton, we might think, we take classes to learn and to prepare ourselves for independent work, but the two are distinct concepts. But reality is, of course, much more complex: classes at Princeton can and do incorporate elements of independent research work. This spring break, I had the opportunity to conduct field research as part of one of my classes, GEO 372 (Rocks!). We flew down to Death Valley National Park for a week, collecting various rock samples and learning about the regional geology. For the rest of the semester, we’ll be analyzing the samples to answer our given research question.
Our first day was spent doing a round of “geo-tourism,” as Blair, our professor, called it: we would drive around the park for the day, hitting various notable sites and exploring their geologies. At Dante’s View at the beginning of the day (see picture), we got a bird’s eye view of the entire park from 5500 feet: an ideal place to see the big geologic picture. From here, we could see the snow capped Panamint Mountains, created by tectonic uplift millions of years ago. Below it were the lowest elevation lands in all of North America: the salt flats of Badwater Basin (-282 feet).
As we explored the park and arrived at new sites, our instructors never initially told us the exact geological histories and relevance of these sites. Instead, we looked for clues of Earth History in the grounds around us: a perfect example of real-world field research! We determined that the rocks at Zabriskie Point were lacustrian (lake) sediments, deposited by the ancient lake that once covered all of Death Valley before it evaporated away. At the aptly-named Mosaic Canyon, we determined that the grand, imposing canyon walls were made up of piles of sediment (“cap carbonates”) deposited after the “Snowball Earth” episode 600 million years ago. During Snowball, the Earth was entirely covered in ice, with glaciers stretching from the poles to the equators: once that ice melted, sea levels massively rose, and this is when the cap carbonates were deposited.
The next day, it was the turn of my research group to collect our samples. We drove to Monarch Canyon, a site slightly outside the National Park boundaries and home to an intriguing “metamorphic core complex.” Metamorphic rocks are rocks created by alteration of existing rocks due to high temperature and pressure.
As we walked down the canyon, we could see the “metamorphic grading” increase: essentially, further and further along the canyon, the rocks that made up the canyon walls were formed at increasingly greater pressures and temperatures. Our project was to map this metamorphic grading to quantitative pressure and temperature values.
The first step was to take samples. Using our rock hammers, we hammered away chunks of interesting-looking rock at regular intervals. Each of these samples contained unique sets of minerals: our hope was that we could analyze their unique mineral composition such that we could reconstruct the pressure and temperature conditions when they formed.
Once we took the samples in the field, we transported them back to Princeton. Our first step once back was to cut them with a rock saw to a certain specification, such that we could send them to a specialized lab to create “thin sections”—little, 30-micron-thick slices of rock that we could look at under a microscope to analyze the mineral composition.
Right now, we’re waiting for the thin sections to be made. It’s just one part of our research project journey—yes, a full research journey in a class, from fieldwork to labwork to data analysis to writing. To have the full experience of performing a research study in a class setting is really incredible, and I’ve been having so much fun while doing it!
—Advik Eswaran, Natural Sciences Correspondent
