Intrasource Chemical Variability of Artefact-Quality Obsidians from the Casa Diablo Area, California

doi:10.1006/jasc.1994.1026

Journal of Archaeological Science

Volume 21, Issue 2, March 1994, Pages 263-271

https://doi.org/10.1006/jasc.1994.1026 Get rights and content

Abstract

Obsidian from the Casa Diablo area of Mono County, California, was an important source for artefacts and raw material in prehistoric California, although little work has been devoted to investigating the potential geochemical variability within the many quarry areas it contains. In this study, 200 obsidian source samples from 20 collection locations in the Casa Diablo area were analysed by energy dispersive X-ray fluorescence spectrometry. Laboratory analyses of solid flake and powdered obsidian samples are presented in quantitative measurement units (parts per million and/or weight percent composition) calibrated to international rock standards. The results of this research indicate that two—possibly three—geochemically distinct varieties of artefact-calibre obsidian exist within the source area once believed by archaeologists to be a single geochemical entity. These new findings carry implications for obsidian trade/exchange systems studies in California and the Great Basin, and for obsidian sourcing research in other areas of the world.

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Cited by (49)

Introducing the Peabody-Yale Reference Obsidians (PYRO) sets: Open-source calibration and evaluation standards for quantitative X-ray fluorescence analysis
2019, Journal of Archaeological Science: Reports
A series of well-characterized specimens, known as the Peabody-Yale Reference Obsidians (PYRO) sets, has been designed to aid with calibrating and assessing X-ray fluorescence analysis (XRF) data, including portable XRF (pXRF) measurements, for obsidian sourcing. Each of these ten matched sets consists of 35 specimens: 20 specimens for calibration and 15 specimens for evaluation. These sets include not only obsidians with common geochemical compositions (i.e., alkaline rhyolites) but also rarer ones (i.e., peralkaline rhyolitic, trachytic, and andesitic specimens, including East African Rift obsidians). When used as described, the PYRO sets are suitable to calibrate and evaluate XRF data for obsidians worldwide. A set can be borrowed following loan policies of the Peabody Museum of Natural History, which will also accession a set. Publishing all source information – from their names and GPS coordinates to the datasets used for the recommended values – not only allows the sets to be replicated by others but also fulfills the demands of scientific transparency. Their main purpose is facilitating collaborations and “big data” projects, and the PYRO sets were designed to complement existing protocols for calibration and evaluation. In short, the sets are intended as a tool for almost anyone (e.g., a student who borrows an instrument to source artifacts) to meet – and even exceed – experts' practices involving transparency, accuracy, and reproducibility.
Obsidian studies in California archaeology
2018, Quaternary International
Citation Excerpt :
For example, a few years after its beginning at the UCLA, Fredrickson established an OHD laboratory at Sonoma State University, where thousands of hydration readings from sites throughout California and elsewhere in the far west were made from 1979 to 2002. Since the early archaeological ‘sourcing’ work of Jack (1976), Jack and Carmichael (1969), Jackson (1971, 1973, 1974), and Ericson (1977, 1981), numerous studies have been published documenting the geochemical composition of obsidians erupted within the state (Stross et al., 1976; Hughes, 1982, 1986a; 1986b, 1988; 1989, 1994a; Hamusek-McGann, 1995; Jackson, 1989; Shackley, 1994; Eerkens and Glascock, 2000; Ericson and Glascock, 2004; Hughes and Howe, 2017) and these served to ground synchronic and diachronic studies of trade, exchange, and prehistoric material conveyances (Ericson, 1981; Hughes, 1986b; Jackson, 1986; Jackson and Ericson, 1994; Hughes and Milliken, 2007; Eerkens and Spurling, 2008; Brady, 2011). Although most of the major eruptive centers in the state have been geochemically characterized (see Fig. 1), small obsidian nodule sources are discovered from time to time.
This paper traces and reviews the conduct of obsidian studies in California, with emphasis on the results of provenance studies and hydration dating over the past few decades. Review of substantive results reveals temporal and spatial change in the distribution of certain obsidians in different regions within the geopolitical boundaries of the state, as well as evidence for variation in source-use commensurate with different socio-ceremonial contexts in prehistory. Perspectives and lessons on obsidian use, derived from California studies, can be extended more generally to obsidian studies elsewhere in the world.
Trace element characterization of obsidian from the Transcarpathian Ukraine
2018, Journal of Archaeological Science: Reports
Citation Excerpt :
Following these corrections, intensities were converted to concentration estimates by employing a least-squares calibration line established for each element from analysis of up to 30 international rock standards certified by the U.S. Geological Survey, the U.S. National Institute of Standards and Technology, the Geological Survey of Japan, the Centre de Recherches Petrographiques et Geochimiques (France), and the South African Bureau of Standards. For additional details on X-ray tube operating conditions, calibration, artifact-to-source (sensu Hughes, 1998) attribution, and element-specific measurement precision see Hughes (1994, 2015). Table 3 presents the results of geological source reference standards, and Fig. 2 shows that the Sr and Zr concentrations in this glass are significantly distinct from other varieties of Carpathian obsidian.
Non-destructive energy dispersive X-ray fluorescence (EDXRF) analysis was conducted on geological obsidian references samples from Carpathian 3 localities within the territory of the Ukrainian Transcarpathia. These data augment the trace element “signature” for this chemical variety of obsidian, which we applied to compare with trace element data determined on obsidian artifacts from nearby archaeological sites. The results: 1) document the local use and importance of Carpathian 3 obsidian, and 2) show use of non-local (Carpathian 1) volcanic glass at local geological outcrops of Carpathian 3 obsidian, suggesting prehistoric conveyance of Carpathian 1 volcanic glass in to Ukrainian Transcarpathian archaeological sites during the Upper Paleolithic period.
On the sources and uses of obsidian during the Paleolithic and Mesolithic in Poland
2018, Quaternary International
Eighty-six obsidian artifacts from twenty Paleolithic and Mesolithic archaeological sites in Poland were analyzed using non-destructive energy dispersive x-ray fluorescence (EDXRF) analysis and assigned to parent geological obsidian source (chemical type). Results of the study— the first country-wide survey of its kind—support the conclusion that the geological source of obsidian remained largely unchanged for thousands of years, that obsidian use appears to have been minimal throughout the Paleolithic and Mesolithic regardless of distance to source, that obsidian artifacts were used to perform the same functions as their non-obsidian (flint and radiolarite) counterparts, and that the distinct visual properties of volcanic glass may have contributed to its recognition as unique and exotic in different social contexts.
Beyond the colonial curtain: Investigating indigenous use of obsidian in Spanish California through the pXRF analysis of artifacts from Mission Santa Clara
2016, Journal of Archaeological Science: Reports
Citation Excerpt :
Two other common sources from the North Coast Ranges are Borax Lake and Mt. Konocti, located further north in the Clear Lake Volcanic Field (Jackson, 1989). The final three sources of obsidian are found in the eastern Sierra Nevada: Bodie Hills and Casa Diablo, of which archaeologists recognize multiple subgroups including the Lookout Mountain and Sawmill Ridge localities included in this analysis (Hughes, 1994). Five nodules or fragments from each geological source were analyzed, with three separate runs on different surfaces of each piece in order to capture a range of chemical data.
Obsidian artifacts recovered from Mission Santa Clara in central California (1780s–1840s) provide the opportunity to evaluate the persistence of regional economic connections and stone tool technologies in the California missions. Portable x-ray fluorescence (pXRF) analysis was conducted on a sample of 1020 obsidian artifacts, which could be linked to five major geological sources of obsidian found in different regions of California. Obsidian source profiles from features in different areas of the site indicate differential access to or preference for obsidian from particular sources. Despite the small size of many of the obsidian artifacts in the sample, this study found that the use of pXRF was suitable for assigning small artifacts (> 0.3 cm) to regional obsidian sources. The results illuminate the connections that native people living in mission contexts may have maintained to outside resources and provide the basis for further investigation into indigenous stone tool traditions in colonial contexts.
Prehistoric Obsidian Conveyance in the Eastern Great Basin: Evidence from Hogup and Danger Caves, Utah
2015, Journal of Archaeological Science: Reports
Energy dispersive X-ray fluorescence analysis of typologically distinctive obsidian projectile points from Danger Cave (42To13) showed that a change in source-use occurred after the time arrow points supplanted dart points at the site. To determine whether or not this change occurred elsewhere in the region, a sample of typable obsidian points was analyzed from nearby Hogup Cave (42Bo36). The results of the Hogup Cave analyses show that the source material used to make certain series of dart points (Northern Side-notched and Gatecliff series) was largely restricted to local source, but when arrow points began to be used, a significant proportion came from more distant obsidian sources. Taken together, the results of the Danger and Hogup Cave analyses suggest that, at least in this part of the eastern Great Basin, the introduction of the bow and arrow may have expanded social contacts, increased the foraging radius and material conveyance opportunities, and contributed to altering the social organization of peoples using the new technology.

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Regular ArticleIntrasource Chemical Variability of Artefact-Quality Obsidians from the Casa Diablo Area, California

Abstract

Regular Article
Intrasource Chemical Variability of Artefact-Quality Obsidians from the Casa Diablo Area, California