Reports the results of the XRF analysis of 132 artifacts from a severely disturbed site on Butte Creek in the Western Cascades of Oregon. We took a look at this particular site because it lay in a geographic area in which almost no previous provenience studies had been undertaken. The trace element analysis of these artifacts not only demonstrated the utility of obsidian studies at disturbed sites, but also provided an example of the serendipitous good luck that sometimes accompanies a geochemical fishing expedition like this one - a new local obsidian source was identified.

Reports the results of XRF analysis of an obsidian biface fragment from the Fort Hill Hopewell Site in Ohio. Obsidian Cliff in Yellowstone National Park proved to be the geologic source of the artifact. The results of this report were the basis for an article that appeared in Archaeology in Eastern North America 26:33-39 (1997 - Bradley Lepper, Craig E. Skinner, and Christopher M. Stevenson).

This report is a bit more complex than our average model but contains the results of some interesting experimental studies that we conducted on the effects of heat on obsidian hydration rim measurements and rim survival. The analyzed artifacts were collected from two sites that had been severely burned in a 1993 forest fire in the Deschutes National Forest of Oregon. For more information on the effects of fire on hydration analysis, see the Other Articles and Report section below.

During the PGT-PG&E Pipeline Expansion Project (PEP) carried out in the early 1990's, over 9,500 obsidian artifacts from 133 Oregon, California, and Idaho archaeological sites were selected for obsidian characterization studies (Table 1). The trace element composition of 9,059 of these items was determined by X-ray (XRF) fluorescence spectrometry and the resultant elemental abundances were used to identify the geochemical sources of the samples (Skinner 1995a). All Oregon and Idaho artifacts were analyzed by Richard E. Hughes (Geochemical Research) who, along with BioSystems Analysis, also characterized the California specimens. After geologic source identification, the majority of the obsidian artifacts were then examined for the presence of obsidian hydration rims. Several chapters, including all of those associated with the obsidian studies, may be downloaded here.

Abstract: The Little Lake biface collection comprises 26 complete biface preforms. The bifaces are believed to have been found in a cache acquired near the vicinity of the town of Little Lake, Inyo County, California. All the complete bifaces have hydration values falling within a very tight range measuring from 3.5 to 3.8 microns and were determined to have come from the West Sugarloaf subfield of the Coso quarry cluster. These rim readings signify a brief single episode of time and would date to the very late Haiwee or the early Marana Periods in the Owens Valley cultural sequence or ca AD 1300. The cache would lend some limited support to the continued use of large biface cores as a means of production and transport of portable units of toolstone significantly later than might be expected in a volume/mass that is surprising.

The Northern Great Basin Prehistory Project is a joint undertaking of the University of Oregon (UO) Archaeological Field School, UO Department of Anthropology, Museum of Natural History, Department of Geography, and Office of Summer Sessions, the Lakeview, Prineville, and Burns District Offices of the Bureau of Land Management, the Deschutes (Bend) and Malheur (John Day) National Forests, and the Sundance Archaeological Research Fund and Department of Anthropology, University of Nevada, Reno (UNR).

If you have an interest in the effects of fire on obsidian artifacts, this is a must-have publication. This volume consists of 14 papers based on presentations given at a 1999 symposium, The Effects of Fire/Heat on Obsidian, that was held at the 33rd Annual Meeting of the Society for California Archaeology (Sacramento, California). To download a short (260K) additional erratum sheet, click HERE

Abstract: Seventeen known and four unknown sources among 90 obsidian artifacts were identified from the Lost Dune and McCoy Creek sites on the east side of Blitzen valley, Harney County, Oregon. Changing distributions and abundances of obsidian sources identified in four prehistoric periods (3,500-2,000 B.P., 2,000-500 B.P., A.D. 1400s and A.D.1500s) suggest eastern Blitzen Valley people used a limited resource area in the middle two periods. For the period from 2,000 to 500 B.P., obsidian was identified only from sources in and adjacent to Harney Basin and in the northern Catlow Valley - the "western Malheur.Catlow area. Then, briefly in the A.D. 1500s, pottery-using visitors brought to Lost Dune ample obsidian from sources well east of Harney Basin in the Owyhee River drainage.

From the Abstract: Nonhydrated obsidians are quenched magmatic liquids that record in their chemical composition details of the tectonic environment of formation and of the differentiation mechanisms that affected their subsequent evolution. This study attempts to analyze, in terms of geologic processes, the compositional variations in the Subalkalic obsidians... New major- and trace-element determinations of 241 samples and a compilation of 130 published major-element analyses are reported and interpreted.

From the Abstract: Peralkaline rocks are one of the characteristic products of non-origenic magmatism, and the development of peralkaline silicic magmas continues to be a problem of special interest to petrologists. The problem is complicated by the fact that crystallization of these highly alkaline melts commonly result in significant chemical changes, such that the study of quenched liquids (glasses) is probably the only reliable approach to magma compositions. In this report, all acceptable analyses of oversaturated peralkaline obsidians are listed and compared in an attempt to provide a sound basis for further studies of peralkaline silicic magmatism.

This unfinished report by Nevada archaeologist Joe Moore (now retired but formerly of the Nevada Department of Transportation) was last substantially updated in about 2002. Although the toolstone project remains incomplete, much of the information it contains (both the data and the source information) is unavailable elsewhere. And so, with our thanks and the permission of Joe, we present the report in it's most recently updated version.

This piece of research, the first substantial one that we finished under the name of Northwest Research, was completed in 1991. We always felt that this was a nicely done investigation although the final project report susequently disappeared deep into the vast murky reservoir of U. S. Forest Service gray literature. For more on the project, click HERE.

Abstract: Technological debitage analysis can be an aid in assessing discard context, as well as overall site integrity. Related to this is the well-known use of obsidian hydration to identify scavenging behavior. Obsidian hydration cut locations are often determined in the obsidian lab; the archaeologist soliciting the hydration assessment does not usually select the specific locations. By identifying features on the artifact that can be attributed to particular reduction techniques or methods and acquiring hydration measurements from those locations, transformational processes and prehistoric behavior are better elecited. An example from an archaeological site located in the southern San Joaquin Valley of California is presented.

Introduction: Danger Cave (42To0013) is located on the western edge of the Bonneville Basin, within Tooele County, Utah, just north of Wendover, Utah. It is a classic Great Basin site containing well stratified deposits that have a high degree of organic preservation and are well dated. It contains rich evidence of cultural occupations spanning the terminal Pleistocene and Holocene. Obsidian artifacts, including some debitage with provenience, are abundant in the assemblage, yet the site is quite distant to viable geologic sources of obsidian. XRF analysis of obsidian tools and debitage sampled throughout the site display a pettern of source use through time that can be used to investigate land use patterns and interactions within and outside the Bonneville basic of northwestern Utah. Results of this sourcing investigation indicate a broad geographic range of obsidian procurement through time with a heavy focus on use of the Brpwns Bench geochemical group.

Abstract: A study of obsidian procurement in Washington County, Utah, allows an examination of mobility and cultural interaction. on the fringes of the Great Basin. Presented here are XRF data from 58 pre-contact archaeological sites ranging from early Archaic to ca. 600 B.P. The wide temporal range provides an excellent opportunity to evaluate shifting obsidian procurement strategies through time. Source provenance datashow great similarity to assemblages from elsewhere in the eastern Great Basin, but distant sources in these assemblages may help to illustrate the area's connections to other parts of the region. [Email: aestevenson13@hotmail.com]

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