Sequencing Analytical Methods for Small Sample Dating and Dye Identification of Textile Fibers: Application to a Fragment from Seip Mound Group, Ohio

Abstract

Examination of fibers from a colored fabric fragment from Seip Mound Group, Ohio, demonstrates the utility of sequencing analytical techniques: (1) minimally destructive pretreatment to remove humic acids followed by plasma-chemical oxidation, in preparation for accelerator mass spectrometric determination of radiocarbon age and (2) direct analysis in real time mass spectrometry (DART-MS) of the pretreatment solution, for the determination of red colorants. Pretreatment followed by plasma-chemical oxidation provided the opportunity to date 3 mg of fiber using just 200 mcg of carbon. Examination of the pretreatment solution by DART-MS confirmed the composition of anthraquinones consistent with those from bedstraw root (Galium sp.). The date determined (1,805 ± 35 B.P.) places the textile in the midrange of radiocarbon dates previously obtained for the Seip earthworks; identification of the dye plant shows that the Hopewell possessed a sophisticated knowledge of plants and their uses.

keywords:

• DART-MS
• radiocarbon date
• dye
• textile
• Hopewell
• Ohio

Acknowledgments

The AccuTOF-DART mass spectrometer was purchased under NSF MRI-R² award #0959621. The authors gratefully acknowledge funding support provided by the Eastern Michigan University Provost's Office Faculty Research Fellowship and Research Support Awards, the Eastern Michigan University Chemistry Department, and the Sellers Fund. Annette Ericksen, ASC, Inc., Columbus, Ohio, provided helpful comments and suggestions about the Ohio Hopewell experience. Eastern Michigan University student Calvin Day helped develop the DART-MS methods used in this work. The Ohio History Connection, Columbus, Ohio, provided access to the Seip collection and granted permission for examination of the Seip textile fragments, as well as underwrote the funding for the AMS radiocarbon date. Two reviewers provided additional helpful comments.

Notes on contributors

Ruth Ann Armitage is a professor of chemistry at Eastern Michigan University, Ypsilanti. Her research has focused on developing analytical methods to study archaeological materials, like rock paintings and textiles, to better understand human behavior in the past.

Kathryn Jakes is professor emerita at Ohio State University, Columbus and an independent scholar in archaeological textiles. Her research throughout her career has been uncovering clues to the past through analysis of archaeological and historical textile materials.

ORCID

Kathryn A. Jakes http://orcid.org/0000-0002-4529-1839