Archaeometry and Museum Collections

Mark Golitko, Associate Editor for Lithics and Network Analysis

pXRF and other more affordable and accessible methods of materials characterization have led to a massive increase in the generation of archaeometric data, particularly for obsidian, as I noted in my last post on this site. The development of portable XRF, portable FTIR, and other non-, minimally-, or quasi-non-destructive techniques have also made studies of objects possible that might not have been two decades ago. For instance, I’m about to head back to my old place of employment, the Field Museum of Natural History, to complete data collection for a project I began nearly a decade ago, using PXRF to source the obsidian blades in large spears and daggers produced in the Admiralty Islands (Papua New Guinea) during the late 19th and early 20th centuries. This project is in collaboration with Robin Torrence (Australian Museum), and builds on her prior work (Torrence et al. 2012, 2013) on similar spears and daggers from the Admiralties housed in museum collections in Australia and the UK. Our work examines how producers there responded to a sudden massive increase in demand for these objects as museum and private collectors developed an interest in ethnographic objects during the “golden age” of museum collecting. Torrence had already found that the quality and variability of haft design appeared to decline as producers became concerned with pumping out as many spears and daggers as possible (Torrence 1993). Preliminary PXRF results suggest that they also broadened obsidian procurement—spears and daggers produced before ~1900 are exclusively made on obsidian from Lou Island (Torrence et al. 2012), while sources on Pam Island appear in 20th century spears and daggers. Some of these blades may actually have been produced centuries or even millennia earlier and reused as demand increased—the production of large obsidian blades has a history stretching back to the mid- Holocene in the Bismarck Archipelago (Fredericksen 2000; Torrence et al. 2013).

An obsidian bladed dagger produced in the Admiralty Islands (image courtesy of wikicommons).

A recent paper in Antiquity (Cambell et al. 2021) uses PXRF to source obsidian mirrors housed in the British Museum collections, including one once owned by the Elizabethan era polymath and mystic John Dee. While there has apparently been some debate over the authenticity of this object, the authors conclusively show that the obsidian from which the mirror was made originated at the Pachuca source flow in central Mexico, the primary source utilized by the Aztec empire, as does another mirror in the British Museum. Two other objects analyzed as part of the study (one mirror and one polished block) originated from the Ucareo source, within the bounds of the neighboring Tarascan empire. The symbolic associations of these objects were complex and multivalent in central Mesoamerican mythology, being used in healing, as a symbol of royal power, for human sacrifice, and as a prosaic material for tool manufacture. Mirrors themselves had numerous associations, including protection from evil spirits (Darras 2014; Pastrana and Athie 2014). The Campbell et al. study documents the interesting process by which objects used for these purposes were appropriated for broadly similar purposes by Dee (who hoped to commune with angels and other supernatural beings), but in contemporary European society, Dee’s use of the mirror was considered a form of black magic.

References

Campbell, S., E. Healey, Y. Kuzmin, and M.D. Glascock. 2021. The mirror, the magus and more: reflections on John Dee’s obsidian mirror. Antiquity 95: 1547-1564.

Darras, V. 2014. Ethnohistorical evidence for obsidian’s ritual and symbolic uses among the Postclassic Tarascans. In Obsidian Reflections: Symbolic Dimensions of Obsidian in Mesoamerica, edited by M.N. Levine and D.M. Carballo, pp. 45-74. University of Colorado Press, Boulder.

Fredericksen, C. 2000. Points of discussion. Obsidian blade technology in the Admiralty Islands, 2100 to 50 BP. Indo-Pacific Prehistory Association Bulletin 20: 93-106.

Pastrana, A., and I. Athie. 2014. The symbolism of obsidian in Postclassic Central Mexico. In Obsidian Reflections: Symbolic Dimensions of Obsidian in Mesoamerica, edited by M.N. Levine and D.M. Carballo, pp. 75-110. University of Colorado Press, Boulder.

Torrence, R. 1993. Ethnoarchaeology, museum collections and prehistoric exchange: obsidian tipped artifacts from the Admiralty Islands. World Archaeology 24(3): 467-481.

Torrence, R., P. White, and S. Kelloway. 2012. Expanding the range of PXRF to ethnographic collections. IAOS Bulletin 46: 9-15.

Torrence, R., S. Kelloway, and P. White. 2013. Stemmed tools, social interaction, and voyaging in early-mid Holocene Papua New Guinea. The Journal of Island and Coastal Archaeology 8(2): 278-310.