Luke Burds and Ricky Mataitis examined data gathered from two separate ground-penetrating radar readings

(Front, from left) Luke Burds and Ricky Mataitis examined data gathered from two separate ground-penetrating radar readings. Andy Brown, the AGES Lab data manager, (background) chimed in on a conversation about their findings from the Redeemer Lutheran Cemetery.

On May 30, the Herald met with a professor from Minnesota State University-Mankato and his team, whose help was enlisted by Pastor Diane Goulson of Redeemer Lutheran Church outside of Belle Plaine. On July 3, we followed up with them for an update as to what they are finding and what it all means. Keep an eye on future issues of the Herald as we delve into key findings, history and the science of the ongoing project, as well as various facets of the world of archaeology.

by Casey Ek

Cans of energy drinks lined a desk and a spot on the floor of Trafton North Hall’s room 355 on the Minnesota State University campus in Mankato Wednesday, July 3. Wires stemming from multiple directions, including from the ceiling,  bundled near a high-powered computer tower and multiple smaller towers, while the team from the university’s Archeology, Geography and Earth Sciences (AGES) Research Laboratory stacked, compared and rendered thousands of data points gathered from Redeemer Lutheran Cemetery over the last month or so.

One peering at grad student Luke Burds’s computer screen might confuse its content for an audio file; several horizontal waves represented in black create linear ripples over a gray surface. But the image on Burds’s screen was in fact a profile representation of a section of land at the Redeemer Cemetery.

Next to Burds sat Ricky Mataitis, a fellow grad student working with Burds to make sense of the readings from the AGES Lab’s ground penetrating radar.

To make matters more nuanced, they’re looking at two separate readings of the same areas using ground penetrating radar readings of two separate frequencies, 200 megahertz and 500 megahertz.

The use of two readings proved itself particularly useful in the Redeemer Cemetery due to a consistent problem the team encountered using the higher frequency reading, which produces more detailed images of subterranean material, but in exchange are effective to shallower depths compared to the lower-frequency readings that are useful to greater soil depth but produce less detailed images. The problem was that their ground penetrating radars kept fizzling out at about a foot and a half into the soil. Burds stated that the AGES team has an idea as to why that’s consistently the case throughout the cemetery.

“The inference was that the cemetery is on clay-rich soil, which is not useful for the type of testing because the tools have a really hard time penetrating that kind of stuff,” Burds said from within the AGES Lab. “So with this really strong contact, it must be a super hard layer, or at least like a clay lens.”

So in response, the team has moved to examining the soil itself as a means to better understand what materials lie at what depths. This, Burds says, might help explain the ground-penetrating radar readings expressing that there are ‘definite buried objects’ beneath the surface. Considering the depth of their hits coupled with the fact that the team was finding a high number of small anomalous readings, they have at least one potential explanation for their findings.

“One of the hypotheses that we’re thinking of or trying to go off of right now is that what we could be seeing could be child coffins. If you think about it, clay is extremely hard to dig through, and on top of that, you’re dealing with clay that’s already hard to dig through in the summertime, and when the ground is frozen, there’s no way you’re digging through that.”

Dr. Ron Schirmer from MNSU’s Anthropology Department stated that the number of small anomalies greatly exceed the number of large anomalous readings that would be consistent with the size of an adult grave.  He added that the notion of a high number of infant graves would be consistent with what he is finding in Redeemer’s birth and death records. The records, written in German and dating as far back as the 1850s, posed an initial hurdle for Redeemer’s Pastor Diane Goulson, but as an expert in genealogy, Schirmer happens to be fluent in the language.

Moving forward, the team will compare their findings from an augured soil sample taken from just outside the cemetery and compare it with those taken on the sites where they found anomalous readings.

This process, which has Goulson’s blessing, will be performed with the utmost care and precision possible so as not to potentially disturb any could-be subterranean grave sites, according to the team. Schirmer, an expert on identifying the organic components of soils, feels assured that the team will have no trouble avoiding  the disturbance of any graves. They’ll also avoid probing to a depth that would be a grave, Schirmer added. In short, the team wants to determine whether anomalous readings are clumps of soils, glacial till  or other naturally occurring phenomenon, or if they are what the team believes they are - graves.

“If the non-natural concentrations of gravel extend deep into the soil, it’s because they are grave shafts, but if they remain fairly shallow, they’re the remnants of black dirt piles,” Schirmer wrote in an email.

Also across the AGES Lab from Burds sat Andy Brown, the AGES data manager. On one of his three computer monitors was a 3-D model of the Redeemer Cemetery. One potential outcome of the project is that the team, through combining the information gathered from the cemetery site with the church’s birth and death records, will create a tagged map on top of the rendering that shows who is buried where by name. But the model of that sophistication could be a long way off, given the indeterminate nature of some of their findings coupled with the fact that many graves were unmarked to begin with--this would have been the case if a family, at the time of a family member’s death, could not afford a headstone, Brown said.

Schirmer noted that the oldest graves seem to rest in the northwest corner of the Redeemer  Cemetery. Since each row runs from earliest to latest and from north to south with new rows being placed to the east of the earliest row (with some exceptions), the team might be able to get a sense for who is buried where. Furthermore, when comparing the birth and death records to the number of anomalies found on site, it may be possible to determine which graves are missing or how many burials may not have been recorded.

Schirmer stated that he is finding high infant mortality rates and evidence of clustered minor epidemics that create spikes in deaths among infants and older adults in the eras ranging from the late 1800s to the early 1900s.

The team noted that there is much work to do, but they’re happy to do it.

“It’s all part of the university’s mission to support the community,” Brown said, before turning back to his computer where he looked at several aerial photos he had taken of the site.

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