Research Blog
My research interests include high-resolution monitoring and modeling techniques to better understand groundwater flow in spatially and temporally complex geologic systems. Methods include geochemical sampling of groundwater after recharge events, fracture flow modeling, and the use of thermal imagery from drones. My study sites have included areas in Minnesota, Missouri, Pennsylvania, Florida, and now western Montana. |
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Last week I was up in the Swan Mountain Range surveying some sites to set up stream flow gauges for a groundwater model. At one point while up around 4,400 feet above sea level, I looked over and saw a particularly interesting boulder. Most people might just look at it and say "oh neat, it's kind of wavy," but if you're a geologist you'd likely see it and freak out a little bit (as did I). Those little waves are ripple marks preserved in this particular boulder due to moving water. "Well yes, you're near a river, that makes sense" you might say, except those ripples weren't created after the rock was formed, they were created BEFORE the rock was formed, when it was still sediment. For this particular rock, that was about 1.4 billion years ago, or 1400 million years ago, part of the Belt Supergroup of rocks. Because geologic time is always difficult to wrap your mind around: humans evolved 2 million years ago, dinosaurs went extinct 65 million years ago, Pangea broke up 175 million years ago, and the dinosaurs evolved 240 million years ago. When these ripples formed, life on Earth was "just" starting to evolve beyond bacteria. On top of that, there are details about the ripples that tell us more about what was going where it formed. The shape of the ripples let's us know whether they formed in water that was flowing in a single direction (like a river) or swashed back and forth in two directions (like waves on a beach). These ripples are symmetrical in shape, so they indicate two directions of water movement, such as a beach along the sea. You might say, "But you're on a mountain in Montana, nearly a mile above sea level, there are no seas near you," and you are correct - but a lot can happen in 1.4 billion years. In this case, a lot of uplift and mountain building. Finding something like this is always kind of a trip for geologists because it's like stepping into a time machine. While on the day I found this rock I was nearly a mile above sea level next to a tiny stream and only a little above freezing, 1400 million years ago on this spot I would have been on a beach next to the ocean, which would have made for a nice fieldwork day!
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