Discriminating Quartzite Sources Petrographically in the Upper Gunnison Basin, Colorado: Implications for Paleoamerican Lithic-Procurement Studies

Abstract

Archaeologists lack a protocol for systematically attributing quartzite artifacts to particular geologic sources of the material. This paper, in an effort to begin to remedy that situation, reports the preliminary results of a petrographic study of quartzite samples from the Upper Gunnison Basin (UGB), Colorado. In that region, the overwhelming predominance of quartzite (often > 90 per cent) at most archaeological sites has hampered efforts to ascertain with any certainty the mobility strategies of Paleoamerican (and later) residents. In this study, qualitative and quantitative characterization of texture and grain composition of 50 UGB quartzite specimens led to the identification of six statistically distinct groups of samples. The groups are not arbitrary divisions of the data set; rather, they are meaningful from geologic, geospatial, chronological, and human-behavioral perspectives.

Keywords:

• quartzite
• provenance
• sourcing
• petrography
• mobility

Acknowledgements

We thank the 2009 USU archaeological field school staff, students, volunteers, and visiting colleagues, who spared no energy to climb (nearly) every mountain to collect UGB quartzite and without whom this research could not have occurred. For facilitating sample collection on the lands they manage, we gratefully acknowledge federal scientists Elizabeth Francisco and Dan Haas (BLM Gunnison and Colorado, respectively); Forest Frost, Bill Commins, and Ken Stahlnecker (National Park Service, Black Canyon of the Gunnison, and Curecanti National Recreations Areas, respectively); and Justin Lawrence (Gunnison National Forest). Molly Cannon and Patrick Livingood offered valuable statistical input and Carol Dehler supervised Dalpra's petrographic analysis. The National Science Foundation (BCS-0728664 and BCS-0960077) and the Bureau of Land Management (Gunnison Field Office) provided funding for the research. Finally, we thank the two anonymous reviewers who provided input that helped us improve this manuscript.

Additional information

Notes on contributors

Cody L. Dalpra

Cody L. Dalpra is an anthropology graduate student at the University of Oklahoma in Norman. He earned a B.A. in 2010 from the University of Northern Colorado, Greeley. His research interests include archaeometry, Paleoamerican archaeology, and high-altitude hunter–gatherer adaptations.

Bonnie L. Pitblado

Bonnie L. Pitblado is the Robert E. and Virginia Bell Endowed Professor in Anthropological Archaeology at the University of Oklahoma in Norman. She received her PhD at the University of Arizona in 1999. Her research interests include the earliest occupations of the Southern Rockies and adjacent regions, lithic technology and sourcing protocols, and public archaeology.