Below the surface
UW-Green Bay Prof. John Luczaj may know more about what’s underneath Brown County than the good people who answer Digger’s Hotline.
Well, he may not know where sewer lines and power cables are, but he does know what’s far beneath those in Brown County.
Luczaj is mapping the bedrock of the entire county, determining what kind of rock formations are where, and at what depth they begin and end below the surface.
Working with students and other experts from the Wisconsin Geological Survey, Luczaj hopes to produce a large sub-surface map of the county. He suspects the map will be used by engineers, home builders, pipe installers, well drillers, quarry or gravel pit operators and educators.
“Basically, knowing where the rocks are will help anyone who is doing engineering projects, building projects and potentially quarrying operations,” Luczaj said.
The study also led to the re-discovery of a non-active fault line, which stretches from near Greenleaf to the south. Drilling rock cores in different areas showed the same rock formations appearing at different depths in a linear formation.
“There’s at least 100 feet of vertical displacement along a particular ancient, non-active fault zone, and later this fall we hope to explore this by doing some subsurface techniques like seismic investigations,” said Luczaj, who noted the fault appeared on one very old map. Luczaj added that he and students would be the first to more fully explore the ancient fault.
The project, which is funded through grants from the U.S. Geological Survey and the Wisconsin Geological and Natural History Survey, will continue at least another two years before the maps are completed and published.
Rock formations that were created millions of years ago under ancient seas near the equator certainly can’t be explored overnight.
The Brown County Bedrock Mapping Project
There is a lot underneath Brown County that we don’t know about. And Prof. John Luczaj, a geologist, wanted to find out. So with a grant in hand, he set out to physically map the bedrock of a large portion of Northeastern Wisconsin.
Prof. John Luczaj
Natural and Applied Science
The overall goal of this project is to map the bedrock geology for Brown County. So, students and I here at UW-Green Bay, in conjunction with the State Geological Survey, are working to make 20 quadrangle scale maps, and eventually assemble them into one large map for Brown County.
On the map, we’re going to have each of the different kinds of rock formations, some of which are shale, or dolomite or sandstone, and this will be supplemented by things like cross-sections, showing what’s underneath the ground, and all of the outcrop places where we’ve done the research.
There are a number of people who will probably end up using the map. First of all, for an educator like myself, it’s useful to have an idea of what rocks are in what location. And other people as well will use this map. Engineers want to know the depth to bedrock. Other people want to know whether or not this area would be a good resource for opening up a quarry or something like that. Basically, knowing where the rocks are will help anyone who is doing engineering projects, building projects and potentially quarrying operations.
Students themselves are getting hands-on experience both in the field with John, and in the laboratories.
Some of the things the students do are accompany me in the field. If I go in places where it might be dangerous or where somebody wouldn’t find you if you slipped and broke your ankle, that alone is useful.
Sometimes it’s important to have another set of eyes in the field to look for things, or to measure things, so that’s one of the things students do in the field.
In the laboratory, I have students cutting rocks, like drill cores. Here’s an example of a drill core that’s been cut. And, it’s a time-consuming process, but it’s a pretty handy thing for students to do, so we have them cut rocks, polish them, make thin sections for microscopic study or chemical analysis and a bunch of other things.
Students are also helping me interpret some of the geology in the field. So, they do lots of variable tasks.
Senior, Geoscience major
Comparing textbook learning vs. learning in the field, or learning in the laboratory is having the hands-on is completely invaluable. Just knowing your research and being able to see it, in-hand specimens, in the field and in drill-core, the three specimens can look completely different than just learning it in a textbook. So it’s completely invaluable to have hands-on experience.
Finishing the map takes some time. But when it’s completed, it will be available to anybody who may need it.
Right now we’re in the second phase of a two-year project. In the end of the spring semester, the deliverables, the maps I’m going to make are due for the western half of the county. They’re due to the United States Geological Survey. So, during that mapping process, I use ARC Map, a GIS product, to plot all the locations we’ve visited in the field, plot field locations, and any other subsurface information that we have like well construction reports. So the final map has the geology of the bedrock underneath the soil for all the different parts of the county.
In about two years from now, I hope to have a bulletin published by the Wisconsin Geological Survey, that will have a full explanation of the county’s geology, as well as a large county-scale map of the bedrock.