The volume of most historically observed basalt flows is measured in the fractions of a cubic kilometer, and it is likely that most sources of basalt raw material are relatively small and confined to localized geographic areas. There are notable exceptions to this, however, which points to the need for geologic mapping in areas of basalt characterization studies, for example, one flow of the Columbia River basalt group is estimated to cover 18,000 km2 (Williams and McBirney 1979:98). Geologic mapping in the Lake Tahoe region indicates that outcrops of basalt are limited in their geographic extent, suggesting their high potential for use in trace element characterization studies (Burnett and Jennings 1962; Saucedo and Wagner 1992).
Although the geochemical characterization of artifacts made of basalt and similar volcanic rocks is a relatively new field of investigation, results from research conducted in many areas around the world have been encouraging (see Table 1). Nondestructive trace element characterization studies of basalt artifacts and sources from the Tahoe National Forest by Latham et al. (1992), for example, provided the original impetus for later investigations by BioSystems Analysis and Northwest Research. Extensive trace element studies by Northwest Research of basalt source samples from many locations in California indicate that most geologic sources are relatively homogeneous in their trace element composition, yet demonstrate adequate intersource variability so that individual sources of raw material can be distinguished.
| Europe/Mediterranean |
Antonelli et al. (2004) Capedri and Grandi 2002 Williams-Thorpe and Thorpe 1990, 1991, 1993 Williams-Thorpe et al. 1999a, 1999b Xenophontos et al. 1988 |
| Israel, Egypt, and Jordan |
Goren-Inbar et al. 1986 Greenough et al. 2001, 2004 Mallory-Greenough and Greenough 2004 Mallory-Greenough et al. 1999, 2000 Watts et al. 2004 |
| Japan | Higashimura et al. 1981 |
| North America: United States and Canada |
Bostwick and Burton 1993 Day et al. 1996 Geenough et al. 2004 Jackson et al. 1994 Jones et al. 1997 Latham et al. 1992 Newman and Nielsen 1987 Skinner 1998a, 1998b, 1998c, 1999b, 1999c, 2000a, 2000b, 2001a, 2001b, 2002a, 2002d, 2003a, 2003b, 2004a, 2004b, 2004c, 2004d, 2005a, 2005b, 2005c, 2006a, 2006b, 2006c Skinner and Davis 1995, 1996a, 1996b, 1996c, 1997a, 1997b, 1997c, 1997d, 1997e, 1998a, 1998b Skinner and Thatcher 1998, 2002, 2003a, 2003b, 2003c, 2003d, 2003e, 2003f, 2003g, 2004a, 2004b, 2005a, 2005b, 2005c, 2006a, 2006b, 2006c, 2006d, 2006e, 2006f Skinner et al. 1995a, 1995b, 1995c, 1996, 1997, 1998a, 1998b, 1998c, 1998d, 2001, 2002 |
| Pacific Islands |
Allen and Johnson 1997 Anderson et al. 1997 Ayres et al. 1997 Bayman and Nakamura (2001) Best et al. 1992 Olson 1983 Parker and Sheppard 1997 Rolett et al. 1997 Sheppard et al. 1997 Sinton and Sonoto 1977 Skinner 1999a, 2002b, 2002c Weisler 1990a, 1990b, 1993a, 1993b, 1994a, 1994b, 1995, 1996, 1997a, 1997b, 1998 Weisler and Kirch 1996 Weisler and Sinton 1997 Weisler and Woodhead 1995 Woodhead and Weisler 1997 |
| South America | Ogborn 2004 (Ecuador) |
Basalt artifacts are prepared and analyzed in the same manner as obsidian artifacts prepared for X-ray fluorescence analysis. Experimental studies using powdered basalt samples and intact flakes indicate that nondestructive analyses of basalt yield similar results to those generated by analyses of obsidian samples (Jackson et al. 1994; Latham et al. 1992; Weisler 1993b).