Field and Geochemical Research of Greater Southwestern Archaeological Obsidian Sources and Early Agriculture and Bow Technology at McEuen Cave, Southeastern Arizona.

Dr. Shackley is currently engaged in a number of research projects at the Hearst Museum and continues field and lab research on archaeological obsidian in western North America including northern Mexico. This research continues to involve undergraduate and graduate students in the energy-dispersive x-ray fluorescence laboratory in the Department of Geology and Geophysics. Further information on the laboratory and facilities can be accessed at URL:

http://obsidian.pahma.berkeley.edu/xrflab.htm

Pursuing long-term research on Southwestern obsidian sources, Dr. Shackley has received NSF and Stahl Endowment funding to continue the quantitative analysis of archaeological obsidian from the Southwest and northern Mexico through the Archaeological Research Facility. These analyses are performed in the Department of Geology/Geophysics x-ray fluorescence lab and involve undergraduate lab assistants from the Science in Archaeology course (Anth 131), as well as students pursuing independent study projects. Field research also continues in the search for as yet unlocated sources of artifact quality obsidian, particularly in Arizona, Chihuahua, and Baja California. Analyses of archaeological obsidian from the Southwest is derived from all periods from Paleoindian to Classic period Hohokam and Late Prehistoric, and many regions, and includes some of the Hearst Museum's collections. Recently, Shackley was involved as a consultant on the Arte Rupestre de la Sierra San Francisco, Baja California Sur, a project of the Instituto Nacional de Antropolog'a e Historia (INAH) of Mexico. Former graduate student Justin Hyland and current graduate student Eduardo Serafin were important field and laboratory archaeologists on this project. The project led to the discovery of one of the most intensively used obsidian sources in North America, greatly facilitated by Justin Hyland's dissertation research and project direction. This new source, Valle del Azufre in central Baja California, as well as the overall project was the subject of a major exhibit in the museum during the spring and summer 1994, and was published in American Antiquity vol. 61, number 4, 1996. Most of this data can be accessed at URL:

http://obsidian.pahma.berkeley.edu/swobsrcs.htm

In collaboration with a number of Southwestern archaeologists at the University of Hawaii (James Bayman), Marquette University (Jane Peterson), and the private sector (Douglas Mitchell), Shackley has been pursuing intensive studies of Classic period Hohokam exchange and interaction through obsidian characterization. Preliminary results suggest that obsidian source provenance in major Hohokam centers such as Casa Grande, Pueblo Grande, and Marana mirrors multi-ethnic relationships within the greater Hohokam interaction sphere as well as elite control of resources. These relationships cannot be discerned using other data sets such as ceramics. These results have been published by the group recently in American Antiquity, Journal of Field Archaeology, Journal of Anthropological Research, and the Proceedings of the International Symposium on Archaeometry and reflect funding from NSF, the Stahl Endowment, Southwest Parks and Monuments Association, and the Smithsonian Institution Fellowship Grants. In concert with this research was the large XRF study of archaeological obsidian from classic Salado contexts in the Tonto Basin as part of the Roosevelt Platform Mound study, the largest single CRM project in the world directed by Arizona State University. As a result of this analysis and confirming evidence from ceramics and architecture, two definable contemporaneous and likely consanguineal groups in the basin appear to be maintaining different external or possibly kin relationships with either the Hohokam to the south or the Mogollon to the southeast, possibly signaling different geographic origins for the groups.

In collaboration with Dr. Rosemary Joyce, Director of the Hearst Museum, a fairly extensive XRF study of archaeological and source obsidian from the Lower Ulua Valley in Honduras resulted in the discovery of one to three new sources. The three source groups appear to be chemically related and may be derived from the same magma source. With Wenner-Gren funding to Dr. Joyce, the geological expedition to study the sources will begin in early 1997.

In California, a very extensive XRF study of archaeological obsidian for EarthWorks at the proposed Domenigoni Reservoir near Hemet in Archaic through Late Prehistoric sites is redefining obsidian exchange in southern California. Apparently, early Takic groups from the Great Basin inhabiting the area maintained extensive exchange relationships with the early Yuman groups in the Imperial Valley to the south and elsewhere, while intervening Takic groups to the south did not.

Beginning this summer, Dr. Shackley began research with Dr. Bruce Huckell of the Maxwell Museum, University of New Mexico, at McEuen Cave, a stratified Archaic period rockshelter in southeastern Arizona in the Gila Mountains. The rockshelter has yielded dates in the Late Archaic/Early Formative period, as well as a tremendous number of organic artifacts including baskets, a complete atlatl, dart and arrow fragments, cordage, and early maize cobs. Dry rockshelters are very uncommon in the Southwest, and the project directors are hoping to address the effect of both early agriculture and the advent of bow technology on hunter-gatherer society. Fieldwork in the summer of 1997 including graduate students from UNM and Eduardo Serafin from UCB, funded in part by the Stahl Endowment, indicated a large area at least 10 X 15m that appears undisturbed. Geochemical and hydration analyses of the obsidian artifacts indicate little vertical disturbance in the lower levels. Maize cob fragments both burned an unburned were recovered to the bottom of the deposit (ca. 125cm) and AMS 14C dates currently pending at the CAMS Lab at LLNL may be the oldest thus far recovered in the American Southwest.

Dr. Shackley continues research and curation on museum archaeological collections. The museum, under the direction of Shackley, Rosemary Joyce, and Kathleen Butler, received funding from the National Center for Preservation Technology and Training to digitize the archaeological archive collection. This project will commence in fall 1997.

Recent Publications

Relics, Rights, and Regulations. Scientific American, March 1995, pp. 115.

1995 Sources of Archaeological Obsidian in Greater American Southwest: An update and quantitative analysis. American Antiquity (60)3, in press.

(ed.) 1995 Method and Theory in Archaeological Volcanic Glass Studies. New York: Plenum Publishing Company, in press.

Last modified 9 November 1999.