“…Current research has demonstrated that knowledge of major and trace element variations in obsidians can be used to accurately identify geologic sources of obsidian across the landscape of the Southwest (Judge, 1973;Nelson and Holmes, 1979;Shackley, 1988Shackley, , 1995Baugh, 1991;Amick, 1994;Hughes, 1994a;LeTourneau et al, 1998). Through the use of X-ray fluorescence (XRF) technology, these element variations have been used to identify unique chemical signatures for obsidians which researchers subsequently employ to shed new light on our understanding of prehistoric preference, use, and redis-tribution of lithics in time and space (Shackley, 1990(Shackley, , 1992Hughes, 1994a;Davis, 1995;Dello-Russo, 1997).…”