Laboratory analysis of archaeological artifacts using X-ray Fluorescence spectrometry.

The results of the x-ray fluorescence analysis (XRF) here of 26 obsidian artifacts from an archaeological site in northern New Mexico indicates that the artifacts were produced from one of the three major obsidian sources in the Jemez Mountains, northern New Mexico - Cerro Toledo Rhyolite, El Rechuelos Rhyolite, and Valles Rhyolite (Cerro del Medio) 80-90 km southwest of the site (see Shackley 2005). 

The analysis here of a variety of artifacts from a number of sites or site groups in the El Segundo project area is dominated by obsidian sources along the Jemez Lineament, and a variety of rock types likely typical of the local geology. One piece of obsidian debitage was produced from the Government Mountain source in the San Francisco Volcanic Field or northern Arizona, over 370 linear km west. Government Mountain obsidian has occurred in El Segundo project sites and other Archaic contexts in the Grants, New Mexico area just south of El Segundo (Birkmann et al. 2018). One dacite projectile point base was produced from the San Antonio Mountain source in the Taos Plateau Volcanic field over 250 linear km north.

Laboratory analysis of archaeological artifacts using X-ray Fluorescence spectrometry.

The analysis here of 300 artifacts (12 not obsidian and a few not analyzed) from three sites (SON:F:2:4, 61, and 82) in the Valle de Altar in the northern State of Sonora, Mexico indicates a very diverse provenance assemblage with known sources on both sides of the border, including Arizona, New Mexico, Chihuahua and Sonora, and a large proportion of, as yet, unlocated sources (73.9%) dominated by one unusual trachyte obsidian source (72.9%). The main unknown source is likely located somewhere along the Río Altar or somewhere above that stream basin, and called provisionally here SON Valle de Altar Unknown. The diversity of obsidian source provenance decreases from west to east as the unknown source dominates the assemblage (see cover image). This study is one of the largest archaeological obsidian provenance studies in Sonora, and despite the number of "unknown" sources provides a good basis for further archaeological and geoarchaeological research in Sonora (see also Shackley 2019a).

Laboratory analysis of archaeological artifacts using X-ray Fluorescence spectrometry.

Laboratory analysis of archaeological artifacts using X-ray Fluorescence spectrometry.