What do you get when you cross a geologist with a computer scientist? Easy, a Schmitty Tompson. Part rock nerd and part computer programmer, Schmitty is passionate about reconstructing Earth’s climate history one computer model at a time. Lucky for me, Schmitty is also equally passionate about communicating science with the public, and graciously agreed to meet me on the Oregon Coast for a hike and chat.
Walk and Talk
It was overcast and a bit windy when I pulled into the Cape Perpetua Visitor Center Parking lot, Schmitty and I’s agreed upon meeting place. Schmitty was all smiles and pleasantries, and we soon were on the trail and introductions were underway.
Schmitty is a 5-year PhD student at Oregon State University where they have been studying ice ages (a topic we would spend a lot more time on later), but perhaps might be better described as a Jack-of-all-trades.
“I need to know a little about a lot of different things,” explained Schmitty as we headed down the paved path from the visitor center that leads to tide pools and Spouting Horn. “I learned about glaciers and ice sheets. And I study ocean physics and what the interior of the Earth looks like… It is very interdisciplinary.”
As mentioned earlier, Schmitty is also very interested in public outreach.
“I am happy to do my best to talk about anything else about Earth Science!”
A Rocky Start
Schmitty’s love for science was born from an early age, but it wasn’t until an 8th-grade summer camp where they took a canoe trip into the boundary waters of Minnesota that they realized they could make it a career.
“The person leading the trip had just graduated with a degree in geology and she was telling us about the rocks all around us and I was so fascinated,” described Schmitty. “She was blowing my mind!”
It was during that trip that Schmitty decided that they were going to be a geologist and announced it for the entire camp to hear.
Still, in high school Schmitty found themselves leaning toward a career in computer science. It wasn’t until they were in college that they were able to make the connection back to geology.
“I had a really amazing mentor,” said Schmitty.
Basalt Pools
By this time, Schmitty and I had reached the tidepools and the rough, jagged rocks that hold them.
Cape Perpetua’s rocks are part of the Yachats Basalts that erupted some 37 million years ago along the edge of the coastline of North America.
“They [basalts] can form when a hot spot or plume of magma bubbles up from the earth’s crust and creates this really big active volcanic center,” explained Schmitty.
Basalt also comes in a variety of patterns—sometimes blocky, other times craggy, other times smooth.
Much of what we saw in the tidepools was blocky or columnar. We also saw basalt rock with small vesicles—aptly named vesicular basalt—that form from air pockets in the lava as it cools.
Fractionation
Basalts are not the only type of volcanic rock, however.
“There is a scale of what these rocks are made of,” Schmitty explained. “It starts with ultramafic that are really high in magnesium and iron; low in silica.”
Then there is mafic rock—these are your basalts, and what the ocean crust is made of.
Looking out at the vast ocean, I tried to imagine this rock lying somewhere below the weight of the ocean and accumulating sediments.
Basalt is also incredibly common “because if forms in so many situations.” However, not all rock reaches the surface as mafic rock.
“As magma moves up it cools,” explained Schmitty, “the squishy minerals are mixed, but they cool at different temperatures and ‘fall out’ as they cool.”
This is how more “evolved” volcanic rocks are formed. This process of magma evolving as it rises through the mantle is called “fractionation,” and is responsible for the formation of felsic rocks, like rhyolite, that are higher in silica.”
Schmitty described the process of mantle rising and carrying up magma towards the surface as a process like a pot of water boiling—it is the rising, cooling, and falling that keep plate tectonics and associated processes like volcanism going on the Earth.
“There is a whole world underneath us and we will never see it,” Schmitty observed.
Terraces
After poking around the rocks, a bit longer, we continued on the trail towards spouting horn. Looking back from this vantage point, Schmitty noted a small exposure near the shoreline.
“You can see different layers,” they noted. Cobbles were part of the strata—perhaps an old creek bed, for instance.
Exposures like these are not uncommon along the coast. In fact, as the land has been lifted upwards, there are many places along the Oregon Coast where these exposures exist.
“Sometimes you can get sort of stairsteps,” Schmitty described. “These flat stairsteps are old beaches.”
The overall stair-step landform made up of “old beaches” is called a terrace. Each step was an ancient coastline that was moved “up” by plate tectonics.
Standing on the Shoulders
“Terraces are part of my thesis,” Schmitty exclaimed. “I specifically study sea level rise.”
According to Schmitty, there are a lot of terraces along the Oregon Coast that have been documented and provide an important data set for their research. Combined with other data sets, like those from terraces and reefs along the Atlantic Coastal Plain and Caribbean, Schmitty had what they needed for their thesis.
“Terraces and coral reefs form where the land meets the Ocean,” they explained. “We call these sea-level indicators because they are not in contact with the ocean, but we know they formed at sea level.”
“Why I love these local records they capture these patterns really well,” they continued. “You get these crazy patterns in the indicators. You capture the dynamics going on. It’s like getting an action shot.”
Schmitty’s research involved digging through tons of old papers and records from researchers of the past to try and put together a history of our changing oceans.
They asked me, “Have you heard the phrase, ‘standing on the shoulders of giants?’”
I nodded.
“I stand on the shoulders of field scientists,” Schmitty offered the appropriate accolades. “Awesome people who have spent thousands of hours out there.”
Rise and Fall
The trail paralleled the coastline and its rocky shore. We watched the waves crashing into the basalt formations as we walked. Was the sea level today very different than a thousand years ago? What about 100,000? Or even a million?
Sea level indicators tell the story of change, but the question remains—why has sea level changed?
According to Schmitty, there are a lot of contributing factors from changes in the Earth’s position relative to the sun, as well as the amount of water locked up in ice during any given period.
Fortunately, these changes follow predictable cycles.
“Over the last 2.5 million years, Earth has been descending in and out of ice ages—the more technical term is glacial cycle,” Schmitty explained. “It cools down slowly until it reaches really cold conditions, and we have massive ice sheets covering a lot of the planet…It takes 100,000 years to cool down. Then very quickly it warms up, ice sheets will melt, and it will be like that for a couple of 1000 years.”
The Sun and Earth
What triggers these changes? In short, how the Earth is oriented towards the sun.
“The way the Earth orbits the sun is not constant,” Schmitty clarified. “It is not circular, and it changes over time. How much the Earth is tilted also changes.”
The Earth follows predictable cycles—“100,000 years for Earth’s orbit to change shape, 40,000 years for deep tilt, and 20,000 years for which way it is tilting.”
It is the confluence of all of these cycles that help scientists make predictions about sea level.
Interglacial
These predictable cycles are responsible for glacial periods, like the one that occurred about 125,000 years ago—commonly referred to as the Ice Age. However, they are also responsible for the many cooling and warming periods that occur between “ice ages”—a time period known as an interglacial period.
During an interglacial period, as Schmitty described it—“it cools, warms up a bit, cools, and warms up a bit.” And it is “one of these little warm-up-a-bits” that Schmitty studies.
What’s in a Name
“The one I study happened 80,000 years ago,” Schmitty recounted. “If you want to use the fancy word it is Marine Isotope Stage 5a.”
Say what? I asked Schmitty to decode.
First off, the word isotope just refers to the different varieties of atoms of a given element—for example, carbon-14 vs. carbon-16. The isotopes of an element behave a bit differently depending on how stable or radioactive they are and move differently through the atmosphere and oceans because of their differences in weight. For this reason, the ratio of certain isotopes that exist in certain climate proxies, like those found in deep ocean sediment cores, can tell you something about the climate of the past.
“The one that is relevant to me is oxygen,” explained Schmitty. “It tells you how the temperature changes and how much ice there was on the planet. Someone graphed it a long time ago and it is the peaks and valleys that represent the different isotope stages.”
So, essentially the “little warm up” that Schmitty is studying shows up as a little peak on a graph where the oxygen-18 in proxies were lower and the temperatures a little bit warmer some 80,000 years ago.
Variable
We continued toward Spouting Horn, moving down nearer the rocky shelves of basalt rocks. As we walked, I noticed how some of the basalt rock looked different in color and texture than the surrounding rock. This can occur when new rock is formed within existing rocks creating a geological feature known as a dike.
Interestingly, newly formed rocks are often stronger and more resistant to weathering compared to the rocks that surround them. The results are dramatic and beautiful.
Rocks are not the only thing that is variable. Turns out, sea level is also variable, not only throughout time but also geography.
“It is not just ocean rising,” said Schmitty, “part of it is tectonic plates moving up or down.”
They explained how most people imagine the world ocean like a bathtub with water flowing in through the spout and out through a drain, but it is far more complicated than that.
“One of my favorite things to tell people is that when an ice sheet melts, sea level is going to rise more away from the ice sheet than close to the ice sheet,” said Schmitty.
This may seem counterintuitive at first, but Schmitty explains it, “Ice sheets are really big,” so as they melt the loss of mass reduces the ice sheets’ gravitational pull of water allowing the water to move and disperse away from the ice sheet. Additionally, the weight of the ice sheet also lessens, allowing the ground underneath and around the ice sheet to rise as the pressure is reduced on the Earth’s mantle below.
“This is why I love these local records,” Schmitty exclaimed, they capture these patterns really well! You capture the dynamics going on. It is like an action shot.”
Bringing it Together
Schmitty and I finally made it down to Spouting Horn and watched the waves slosh up against the rocks, occasionally taking to the air through the narrow gap at the top of a sea cave. We didn’t stay long at Spouting Horn. The wind and cool, dampness of the day made it hard to hear or stay still too long. So, we about-faced and headed to the other end of the trail.
As we went, Schmitty told me about the other part of their work—the mathematical part—modeling.
All the local records that Schmitty spent hours upon hours researching needed a model to pull it all together.
“There is a limit to what it [the local records] can tell us,” said Schmitty. Yes, you can identify some patterns in the data, but a model brings context to the records.
“There are things that a model can tell me that geological records can’t tell me,” Schmitty continued. The model uses scientific laws and facts about the physical universe, along with observable phenomena to make predictions about the past.
Specifically, in Schmitty’s case, the model they are working with spits out a slideshow of “what all the past ice sheets looked like and spits out maps of what past sea level looked like around the globe.”
Pretty cool, right?
A Dirty Word
Yet, the word “model” is often considered a dirty word in science writing (whoops).
“Never use the word model if you can avoid it,” Schmitty said was the advice they got regarding science communication.
This advice makes sense when you consider how difficult it is to explain modeling, but on the other hand, maybe that is just the reason it needs to be talked about.
“I think the most underutilized tool is other modelers talking about models,” they continued. “I think I would love to see more modelers talking.”
A Model Model
Schmitty and I were heading north along the trail now hoping to reach Thor’s Well but we hit a roadblock. The trail was closed, and we needed to turn around. But before we high-tailed it back to the parking lot, we stopped at a small turnout in the trail.
Here, I asked Schmitty to elaborate further on modeling. Shying away from the word model, what other words might you use to describe what this thing is?
“I have a computer program,” they begin, but that seems a bit complex too. “I have a lot of code on my computer, and it does math. You have these equations to figure this thing out. The equation does the math, and you get new information out…. I use it to do other science.”
Okay, simpler.
“I always think of it like rules,” I chimed in.
Schmitty agreed. “Yes, it is a set of instructions… I give it something to start with and it gives something out.”
That is what a computer model is in a sense—a model for what a model is.
The Future
We continued back to the parking lot and decided we would drive over to Devil’s Churn before we parted. We hopped into our vehicles, headed north a short distance, and parked.
Once out of the car, we walked over to a viewing area. Foam from Devil’s Churn floated by.
I asked Schmitty if there was anything I had missed in the interview so far. “What else needs to be said?”
“One question that usually comes up,” admitted Schmitty, “is Why should we care about this?”
A very good question. So, what is the answer?
“I am figuring out one piece of a larger puzzle for understanding global warming,” Schmitty began. “If we can put together a really good picture of how the planet changed in the past… that can help us look into the future.”
Schmitty is studying one little warming-up period. But by understanding how ice sheets and glaciers responded and how sea levels changed during that period, they are adding to the breadth of scientific knowledge about the relationship between temperature and changes in the cryosphere adding to the predictive power of the models that project into the future.
“Our present is the key to the past,” Schmitty clarified, “and the present is the key to the future.”
That is how geology works.
Schmitty Thompson is a PhD student in geology and computer science at Oregon State University where they study and model sea level changes during glacial cycles. They are passionate about science communication and getting people excited about geology, however, they want to engage with it. They hope to encourage budding scientists, especially those who are underrepresented in the scientific community, towards a career in science if that is what they are interested in.