by Bill Reardon, Eagle River, Wisconsin
Volume 70, Number 4, October 2023 Central States Archaeological Journal
Figure 1.
The Carbon 14 dating process was developed in 1946 by physicist Willard Libby. It can be used to date organic materials such as wood, bone, and fiber that can be fairly recent and also up to 50,000 years old. Copper is a metal and not organic. Indigenous peoples in this part of North America found that native copper could be used to make items like tools, projectile points, knives, ornaments, and various other items. The vast majority of native copper came from the Upper Peninsula of Michigan and from Isle Royale in Lake Superior. It was either mined or found in scattered deposits from glacial deposition.
Figure 2.
After fabrication of items from the copper, some sort of attachment was required to facilitate a desired use. The attachment device in most cases was wood or plant fiber. In parts of northern Wisconsin, Michigan, Minnesota, and Ontario, Canada, numerous copper artifacts have been found. Copper was not melted but worked cold or through the annealing process (heating, pounding, cooling, and then repeating the process several times). I have found several artifacts that still had remnants of the attachment device in place.
This was usually a small piece of wood or plant fiber. When copper is in the ground for long periods of time it oxidizes, turning a green color. This oxidation process can act as a preservative and keep the organic material in place. Wood and fiber, being organic, can in turn be dated through the Radio Carbon-14 (C-14) process.
Figure 3.
The 12 dated copper artifacts pictured are mostly from Vilas and Oneida Counties of Wisconsin. One artifact (No. 3) is from Florence County, Wisconsin. The dates range from approximately 900 to 8500 calendar years before present (BP). I chose to use dated artifacts mainly from the upper Wisconsin River system. I have had two artifacts dated from Michigan and Minnesota. Eleven of the 12 artifacts were dated by Beta-Analytic of Miami, Florida from 1999 through 2021. Archeologists refer to this group of people using copper as the “Old Copper Culture” or “Copper Complex.”
All the artifacts were found using a metal detector on private land with the owner’s permission. The display of these and other artifacts can be found at the Eagle River Historical Society on US Highway 45 in Eagle River, Wisconsin.
Figure 4.