Rock hunting can be an educational adventure through history
November 9, 2016
Rock hunting is one of the more difficult forms of outdoor recreation. Good sites are challenging to find, loose rocks can pose a safety hazard and the ability to correctly identify fossils and minerals often requires expertise beyond that of a casual explorer.
Geology, however, is an important fundamental concept in understanding basic science, and rock hunting is one of the best ways to learn about it.
“There are so many things about our society that are so complex,” said UW-River Falls Geology Professor Ian Williams. “At least you’ve got to have a cornerstone to start thinking about them.”
Geology and especially paleontology are good, Williams said, at presenting the basic evidence behind concepts like evolution and climate change. Long-dead organisms trapped in rock layers form a record of the earth’s living history and can be excavated and analyzed in order to piece that history back together.
Geology is also useful on a practical level; according to the Wisconsin Geological and National History Survey, Pierce and St. Croix County are part of a large, v-shaped swath of land in the southern part of the state that is prime territory for sinkholes. This is due largely to the makeup of the bedrock—lots of soluble materials like limestone and dolomite—and anyone intending to build in an area would want to know the risks of sinkholes.
Incidentally, some of the more limestone-heavy rock layers in the River Falls area tend to be the ones with the most interesting fossils. One layer called the Platteville formation (found at the tops of hills and easily visible at the high points on road cuts) occasionally holds some intriguing organisms.
“The spectacular ones are trilobites,” Williams said. “Good luck finding them.”
More likely, a person searching through exposures of rock might chance upon a brachiopod. Brachiopods are a group of marine organisms that first evolved about 600 million years ago “when shells first became fashionable,” according to Williams. They closely resemble modern-day clams, but are not in fact from the phylum Mollusca. They belong to a phylum of their own: Brachiopoda. Those found in the River Falls area are typically 470 to 500 million years old.
River Falls, as a whole, is not the best place to go hunting for fossils. Even brachiopods are few and far between, and Williams only recalls at most six instances of anyone ever finding a trilobite (extinct, primitive relatives of the horseshoe crab). A few local quarries and roadside stops hold an ample supply of agates or fossils, but the problems a person will run into there are private property and safety.
Williams’ advice, as a whole, is to find someone who knows what they’re doing to show you where to go and how to go about your search. There are two main options on campus: taking one of the introductory geology courses or joining the Geological Society (Geo Club).
Geo Club, according to its vice president Jacob Tormoen, is largely a way for geology majors to get together, plan their professional careers and expand their experience as geologists, but it is also open for geology minors and even interested students with no academic affiliation to geology whatsoever.
“If you just want to go help and find agates,” Tormoen said, “you can go ahead and tag along for the day and we’re all a friendly bunch of people.”
The club goes on field trips to various fossil/mineral sites, sometimes as far out as the Fossil and Prairie Center in Rockford, Iowa. Issues regarding private property are taken care of ahead of time, and the expertise of people such as Williams or Allison Gale, UWRF assistant professor of plant and earth science, are on hand for learning how best to find and identify different minerals or fossils. Proper training is also provided; rock hunters are taught how to protect against the dangers of falling rocks and how to explore roadside sites without getting hit by traffic.
“If you don’t know what you’re doing,” Tormoen said, “be careful. But always, trying to get people outside and doing what they love is a good thing.”