Discovering forgotten indigenous landscapes with electromagnetic technology

Although monumental earthworks can be found from southern Canada to Florida and from Wisconsin to Louisiana, Ohio has the largest known collection of these structures in the United States—even though Ohio has no federally recognized Native American tribes. Their creators were grouped together under the vague term “Hopewell culture,” named after the family whose farmland was found in one of the first mounds studied. Cultural activities related to Hopewell in the Ohio region from 450 to 400 BC. Areas are considered to be over. Historians of tribes such as the Eastern Shawnee, Miami Nation, and Shawnee believe that the Mound Builders are probably modern descendants—the indigenous people of the continent forcibly displaced by European genocide and now living on reservations in Oklahoma. .

Chief Glenna Wallace of the Eastern Shawnee Tribe is one of those descendants. When we spoke, Wallace was on her way to Washington, D.C., to meet with President Joe Biden for the White House Conference on Tribal Nations. These annual events Wallace recently returned from southern Ohio, where she was visiting sites associated with her tribe’s ancient roots. “The Native American voice was not very strong in Ohio. “Our people did not get the protection they deserved for their actions there,” she said. “The people were made to leave, and our mounds were not taken care of.”

Burks and I drove 70 miles southeast of Columbus to a small family farm in the foothills of the Appalachian Mountains, along roads lined with creeks and roadkill. The trees around us were crisp with autumn leaves. A herd of cattle passed by, their muscular backs attached to the rolling hills in the distance. As Burks completes the 20-minute process of assembling the magnetometer — once complete, it creates a pushcart nearly seven feet wide, weighing roughly 30 pounds — he emphasizes that most of the time he spends searching is man-made hills and mounds. Physically disintegrated long ago. In only a few cases were those earthworks first excavated or surveyed; Instead, they were simply plowed; Bulldozed to build roads, houses and malls; Or, in one embarrassing case, incorporated into the landscaping of a local golf course.

Archaeologists believe these earthworks served as religious meeting places, culturally important tribal burials, and annual calendars, perhaps all at the same time.

Until recently, it seemed that most of the continent’s pre-European archaeological remains had been carelessly removed, uprooted and lost for good. “People see plowing and think it’s completely destroyed the archaeological record here,” Burks said, “but it’s still there. Traces remain: electromagnetic residues in the soil that can be detected using special surveying equipment. Here, in this pasture, there were once at least three round enclosures, he added. Our goal that morning was to find them.

Magnetometry—Burkes’ specialty—can record even minute variations in the strength and position of magnetic fields. As it pushes along the surface, the magnetometer can detect where the fields in the soil below have changed, indicating the presence of objects or structures that may be graves, such as old walls, metal objects, or filled pits. Magnetometry is very good at detecting fires or fires, where the heat can permanently change the magnetism of the soil, leaving a clearly recognizable signature. This means that empty pastures or even community golf courses and suburban backyards can still hold magnetic evidence of ancient settlements that are not visible to the naked eye.

Given such a context, knowing where to start scanning is the first hurdle. Fortunately for archaeologists and ethnographers Ephraim George Squire and Edwin Hamilton Davis – a two-man team in the mid-19th century – they were motivated to learn more about these man-made landforms by preparing as many earthworks as they could find. Destroyed or permanently forgotten. In explaining the rationale for their project, the authors reasoned that the earthworks had received only passing mentions in the logs of other travelers and that they should be “examined more carefully and minutely and, above all, more systematically.” Doing so, they hoped, was “a way of throwing some light on the great archaeological questions connected with the ancient history of the Americas.”