Time Scavengers

Adriane here-

This semester, I am one of our Introduction to Geology course teaching assistants (or TA for short). This class is offered through the Geosciences department at University of Massachusetts Amherst, and this semester, includes over 150 students! The course is designed to introduce our students, who are mostly freshmen and sophomores, to some fundamental principles of geology and important Earth system processes (such as volcanoes, plate tectonics, and earthquakes). Every time the class is taught, which is once a semester, we offer an optional field trip for the students. This trip is held on a Saturday, and we take the students all around the Berkshire mountains of western Massachusetts to show them the major rock formations and tell them the geologic history of the area. In this post, I’ll talk a bit about what we did with the students and why field trips such as these, although optional, are of value.

We began the day at 8:30 am on a rainy October morning. For the trip, about 85 students had signed up. The class TAs, of which there were five on this trip, had decided to each share the responsibility of leading the field trip. We were going to 6 stops altogether, so we each chose a stop at which to talk. Because of the rain, cold, and early start, a large majority of our students didn’t show up. So we left the university with about 65 students in tow!

The first place we stopped was in a nearby town, which is sort of famous. Shelburne Falls was the filming site of the movie ‘The Judge’ starring Robert Downey Jr. and Robert Duvall. But the other (and more important, in my opinion) reason the town is famous is because it contains features called potholes, which were first created when the glaciers glaciers that once covered the area about 20,000 years ago began melting. Potholes are round impressions in the rocks, made by small rocks and pebbles swirling around in a depression in a large rock body. Over time, the small rocks, pebbles, and cobbles carve out a larger and deeper depression. Potholes usually form in or near rivers, as the swirling and moving water is key to their creation.

After we marveled at the Shelburne Falls potholes, we loaded up the vans and took the students into the Berkshire mountains. We stopped at several places in the mountains to talk about the tectonic history of the region, and marvel at the views. Generally, the rocks in the Berkshires have a very long and complex tectonic history. Most of the rocks are a billion to 450 million years old. These rocks are severely faulted (or broken) and folded from orogenies, or times when volcanic island arcs or other continents slammed into North America. The east coast of North America has experienced three different orogenies over the past ~450 million years. From these, the Appalachian Mountain chain was built, which stretches from southeastern Canada south into Alabama. We explained this tectonic history of mountain-building to the students.

But we didn’t just talk about really old rocks on the field trip. We also showed our students more recent geological phenomenon, such as the effects of hurricanes on local river systems. In 2011, Hurricane Irene tracked across western Massachusetts, bringing with it torrential rainfall within just a few days. The weeks before the hurricane hit, several inches of rainfall had already fallen in the area, making the ground saturated. The mixed effects of already-soaked ground, plus additional rainfall, led to landslides in the area. One landslide took out half a road. The damage was so extensive and severe the road was closed for 3.5 months!

The second to last stop we made with the students was to an old marble quarry. The quarry was in operation during the 1800’s into the early 1900’s. However, the mining came to a halt one day when a fire broke out in the barn where the dynamite was kept. This fire, and the subsequent explosions, rocked the town. From then on, the quarry was taken over by the state and made into a state park. And I’m really glad it was: the park is lovely, with a huge marble amphitheater and a river that runs through a carved canyon. The park claims to have the largest natural bridge in the U.S., perhaps the world. I’m not certain if this is true, but the park is lovely. Because the age of the marble is Ordovician (~450 million years old), and I studied this time period during my masters degree, I happily chatted to the students at this stop. I even went full nerd and brought brachiopod and trilobite fossils with me to show the students what types of organisms probably lived in this region hundreds of millions of years ago.

Our last stop was to a local graveyard just down the road from the quarry. Here, the gravestones are all leaning in different directions. They weren’t originally like that, so what caused them to move? It turns out that the graveyard is built on a drumlin. A drumlin is a small hill that was created by the glaciers that covered Massachusetts 20,000 year ago. Because the drumlin is made of sediments that aren’t well consolidated (or packed down), the earth ‘creeps’, or moves. Another way to think of this is the ground is still settling, much like a new house will settle over time on its foundation. After this stop, we packed up the students and headed back to UMass.

Geology is a tricky subject to teach, as a lot of the concepts involve thinking in 3D and sometimes 4D. Learning to think like this takes great practice, patience, and repetition. Field trips such as these expose the students to new concepts and ideas, and we get to teach them these concepts while on the outcrop, looking at the rocks. For example, when talking about the rock formations being smashed together and all pushed towards the west, we can do this while standing in front of a rock with folds and breaks. Using a compass, we can show the students that the folds are pushed, or tilted, to the west from orogenies that I mentioned above. Our students also get more face time with each other, with the TAs, and with the professor. Field trips often create a more relaxed and casual atmosphere than the classroom, so these are great opportunities for students to chat with us (and vice versa) and ask questions they wouldn’t necessarily ask in the class. Having large all-day field trips such as these are also wonderful for students who already are or are thinking about becoming geology majors. These students get a bit more experience with the major and a taste of what’s to come during their degree.

One of the problems in geology is lack of accessibility for students who are hearing, visually, or physically impaired. Because our science takes us outdoors much of the time, this isn’t attractive for students who may be wheel-chair bound or have a disability of any sort. In addition, the geosciences are losing students who did not grow up loving the outdoors, and who may not be comfortable going on day-long field trips. One way to make the class more accessible is to have an alternative option for students who cannot or don’t feel comfortable going outdoors for long periods of time. In our class, we also give the students the option to do the field trip virtually. One of our professors at UMass built a program with images, text, and figures that lets students ‘visit’ local rocks and formations of interest to learn about the geology of the region.

But the all-day optional field trip isn’t just great for our students, it’s also great for the teaching assistants. Because we all took turns talking at different stops, we each got practice talking to a large group of students and explaining geologic concepts. Most of the time, graduate students talk with each other and use science jargon that is not appropriate for undergraduates or the public (they just don’t understand the words we use). Talking with students who have no prior experience with geology makes us think about how we can explain things more thoroughly and simply. Leading the trip together also gives us experience in leadership and teamwork: we all have to work together to make the trip fun, informative, and safe for everyone involved!