A Matter of Suspension: an Experimental Approach to Hammerstone Hafting in Prehistoric Keweenaw Copper Mining

Abstract

For thousands of years before European contact, the vast deposits of copper in the Lake Superior Basin were exploited by the indigenous population of the Upper Peninsula of Michigan and surrounding areas. The copper used and traded by the Native Americans in and around the Lake Superior Basin came from mines on Isle Royale and in the Keweenaw Peninsula of Michigan. In the process of mining, a number of tools were utilized, including both grooved and ungrooved hammerstones. Grooved hammerstones are most commonly found in the Keweenaw while ungrooved stones are most commonly found on Isle Royale. Caches of these hammerstones were found historically throughout the Keweenaw and on Isle Royale but no direct evidence of hafting or handles has been recorded to date. Despite the lack of evidence, archaeologists believe at least some the Lake Superior Basin hammerstones were hafted to aid in mining. This assumption is based on knowledge of prehistoric mining from other areas of the United States and other areas of the world. Lake Superior Basin hammerstone collections have been studied in the context of how they relate to mining and mining activity but never for the purpose of looking for patterns in wear that may indicate if hafting was used and what material the hafting might have been made from. Seven experimental hammerstones were constructed for this project, four with grooves and three without, and used in a manner to simulate mining. Three hammers had wooden handles, two had rawhide handles, and two had no handles. Use wear diagrams were created for the experimental stones and compared to wear patterns recorded on a sample of hammerstones taken from three different hammerstone collections: the Chynoweth Collection, the Drier Collection, and the Massee Collection. The Drier and Massee Collections were collected on Isle Royale in the 19th century while the Chynoweth Collection was collected in the Keweenaw in the early 20th century. The wear patterns on the experimental stones were compared to those on the prehistoric stones and the results do not suggest that distinct wear patterns developed as a result of different types of hafting. However, possible evidence for regional or temporal patterns in wear between the Keweenaw and Isle Royale was identified. The regional specific wear patterns and evidence for the creation and use of stone hammers presented here provide the foundation for further analysis of prehistoric Lake Superior Basin hammerstones.