PETROGRAPHIC AND GEOCHEMICAL SOURCING OF CULTURALLY MODIFIED QUARTZITE IN THE GUNNISON BASIN, COLORADO

As is the case at many very ancient (>7,500 year-old) Rocky Mountain Paleoindian archaeological site, quartzites dominate the late Paleoindian chipped stone assemblage from the Chance Gulch site, located in the Gunnison basin, Southwest Colorado. Quartzites are notoriously difficult to assign to a geological source, yet critical information about the settlement strategies of the prehistoric people who used them could be obtained should archaeologists overcome sourcing challenges.

We report a preliminary attempt to evaluate four techniques for their potential to source 8,000 year-old chipped stone from Chance Gulch: petrographic analysis; x-ray fluorescence; inductively coupled plasmas mass spectrometry; and cathodoluminescence.

The source samples have been drawn from an assemblage of approximately fifty quartzite clasts quarried in June 2005 from secondary quartzite deposits located within about two kilometers of the Chance Gulch site. Using each sourcing technique, we compare Chance Gulch chipped stone artifacts to samples from the natural Gunnison Basin quartzite deposits in an effort to match cultural samples to their point of origin on the landscape.