Intrasource Chemical Variability and Secondary Depositional Processes

Reassessing obsidian field relationships at Glass Buttes, Oregon

“…Glass Buttes is certainly an extreme example, but the complexity of obsidian sources might be more common than widely thought. These findings also reinforce the idea proposed by Shackley (1998), that research on "the field relationships that can influence the chemical variability that hampers our ability to confidently assign artifacts to sources has lagged behind… instrumental advances" (99), which in turn, limits our ability to develop rigorously supported behavioral interpretations.…”

The Analysis of Stone Tool Procurement, Production, and Maintenance

“…Obsidian sources have been widely assessed geochemically and have proven to be fairly reliably linked to archaeological specimens (Bayman and Shackley 1999;Eerkens and Glascock 2000;Eerkens et al 2007;Ferguson and Skinner 2005;Glascock et al 1994;Hughes 1998;Negash et al 2006Negash et al , 2007Roth 2000;Shackley 1998bShackley , 2005Stoltman and Hughes 2004;Tykot 2002Tykot , 2003. Some obsidian provenience studies have been able to reliably recognize ''subsources'' of obsidian and have shown that these sources provide useful information related to human land-use practices (Eerkens and Rosenthal 2004;Young 2002).…”

Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence

“…Sample compositional profiles were compared to geological samples from numerous known and analyzed obsidian sources from throughout the North American Southwest, with source nomenclature following Shackley (1988Shackley ( , 1995Shackley ( , 1998aShackley ( , 1998bShackley ( , 2005Shackley ( , 2009. As there has been progress in XRF analysis of obsidian from Southwestern North America in the decade since this project began, we report sources using our current understanding of obsidian chemistry and source location.…”

“…A subsample of fifty pieces was analyzed by both laboratories to facilitate comparability and this resulted in one group of samples being sourced differently. The New Mexico lab identified artifacts from Mineral Mountain, Utah, while the Berkeley lab assigned the same artifacts to the Cow Canyon source (see below); we have uniformly assigned these samples to the Cow Canyon source based on element profiles and research by Shackley on Cow Canyon materials (Shackley, 1998a(Shackley, , 2005. This probably also means that samples identified by Cameron and Sappington (1984) as from Mineral Mountain most likely derive from Cow Canyon.…”