Have you ever wondered what goes on beneath your feet as you walk on a sidewalk, a prairie, forest, or field? In Southeast Minnesota, we live in a spectacular and ancient landscape. Meandering streams shape our hillsides. Larger rivers cut through the bluffs as water continues its path of least resistance to the Mighty Mississippi. The flowing waters we see today and the water from the receding glaciers that once surrounded the driftless region have sculpted the bluffs, cliffs, and prairies that help represent our home.
Very recently, our region had a day to celebrate. The National Caves Association selected June 6 to be the National Day of Caves and Karst. If you missed it, I’ll fill you in.
What is karst? Karst is a geological term to describe landscapes which usually consist of limestone (or dolostone) and is characterized by disappearing streams, sinkholes, caves, and freshwater springs. The term “karst” comes from the Slovene word “kras” referring to a plateau in Slovenia where the karst topography is present.
The limestone beneath our rich soil is one tenth the age of Earth, and it tells a story. Many of our foremothers and forefathers of Southeast Minnesota settled this land using tools they brought with them and the land itself. Trees became timber; the soil was plowed, sowed, and reaped; the limestone itself was quarried to provide for the foundations of buildings. Every block of limestone that was used represents thousands of years of geological time. The fossils found in this stone are approximately 450 million years old.
It’s no mystery that we do not find dinosaur fossils in our region. Our limestone predates the evolution of dinosaurs by nearly 200 million years. It represents a time when this part of Minnesota, Iowa, and Wisconsin were south of the equator and covered by an inland sea. The water was likely warm, shallow, and calm enough to allow organisms to thrive. Some would later fossilize. To emphasize how long ago some of our limestone was formed, the earliest living jawed fish won’t be found in the fossil record for another 30 million years.
Fillmore County hosts the only two publicly accessible caves in Minnesota; Mystery Cave, located in Forestville State Park and Niagara Cave, near Harmony. Disclaimer: my family runs Niagara Cave. Naturally, we are very excited to have a date designated for caves and karst. We strive to provide an informative tour for people who are interested not only in seeing some of the ancient fossils our region is abundantly supplied with, but also to illustrate that what happens beneath our feet can be seen and felt. We wade through field run-off during times of torrential rain (e.g. all of 2016) not only to clean off decking, but also to protect the fragile stalactites, stalagmites, and flowstone whose growth is inhibited by the settling of heavy sediment from floods.
The Executive Director of the National Caves Association states, “There’s a lot more to learn about the scientific research that’s taking place in caves around the world. Universities are partnering with privately owned caves to learn how unique bacteria can play a role in cancer treatment and the development of new antibiotics. Researchers also collect broken formations to track historical weather trends dating back hundreds of thousands of years and take water samples to identify changes in mineral content.” It is quite clear water quality is not the only area of study through which caves provide a window.
“There’s just so much to see, learn and discover underground,” says Patty Perlaky, president of the National Caves Association. “There’s no limit to the ways that we can benefit by better understanding caves and karst. Astronauts train underground, and NASA is considering the possibility of using a cave to create a shelter on Mars so that only one exterior wall has to be constructed.”
The purpose of the National Day of Caves and Karst is to encourage awareness of the natural environment that includes places like Bluff Country, where humans can physically delve underground and see a reflection of surface erosion, pollution, or land stewardship practices. The next time you drive by a sinkhole in our beautiful countryside, imagine the hidden world below you. Cheers!
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