Identifying mineralogical variation in Baraboo pipestone quarry sources and its implications for Mississippian-era exchange in the midcontinent

Abstract

Pipestones of the midcontinental U.S. have a long history of use by native peoples to craft high status and religious objects, especially pipes, that were often widely exchanged. In this research we describe native use of west central Wisconsin Baraboo Range pipestone as well as identify chemical and mineralogical variation within that formation. The pipestone variants are Baraboo A (dominated by kaolinite, muscovite, and pyrophyllite) and Baraboo B (dominated by pyrophyllite with minor quartz). The recognition of Baraboo pipestone variation allows us to identify previously unsourced pipestone objects. This sourcing project modifies assumptions of Cahokia-centric patterns of earspool manufacture and exchange during the Mississippian period (CE 1000-1400). It demonstrates that Baraboo pipestone Mississippian earspools were quarried, produced, and circulated among a small group of contemporaneous Mississippian societies located in the northern Upper Mississippi River valley — quite outside the Cahokia exchange network. This work establishes that employing rigorous, scientifically sound, and reproducible methodologies to identify the geological source of objects is essential to the interpretation of native interactions.