Minnesota's Obsidian of Anatolia and the Near East (MinOAN) Collection
Latest News: Free Non-Destructive Obsidian Sourcing • Read the Announcement Below
The MinOAN reference collection was assembled by and is currently being studied by Ellery Frahm, a doctoral candidate and research fellow at the University of Minnesota. About 85 percent of these obsidian samples were collected by George "Rip" Rapp, Regents Professor Emeritus of the University of Minnesota and the late Tuncay Ercan of the Mineral Research and Exploration Institute of Turkey (MTA). The collection was later supplemented with samples provided by Giulio Bigazzi of the Institute of Geochronology and Isotope Geochemistry in Italy, Zehra Yegingil of Cukurova University in Turkey, and other geologists who have collaborated with University of Minnesota researchers. Additional obsidian samples came from the University of Minnesota Geology & Geophysics teaching and research collection. The result is a collection of obsidian specimens from over 100 individual flows and source deposits throughout Turkey.
The entire collection is being charactered using electron microprobe analysis (also called electron probe microanalysis) in the University of Minnesota's Electron Microprobe Laboratory, part of the Geology & Geophysics Department. Portions of the MinOAN collection also have been or will be analyzed using mass spectrometry and neutron activation analysis. The full collection has also been analyzed using x-ray fluorescence. In additional, the lab maintains an extensive database of chemical characterizations of Anatolian obsidian from previously published studies. The end product is a rich data set for sourcing obsidian artifacts from Anatolia, Syro-Mesopotamia, and the entire Near East.
Using electron microprobe analysis, rather than mass spectrometry and neutron activation analysis, obsidian artifacts may be analyzed non-destructively. Whole artifacts can be analyzed, as shown above, without sampling so long as the artifact can fit through the airlock. Obsidian artifacts commonly have extremely smooth surfaces, so no polishing is necessary on many artifacts. There are no size-effects in EMPA, unlike x-ray fluorescence, so obsidian fragments as small as a grain of sand can be accurately analyzed. There is no induced radioactive, so analyzed artifacts are safe to handle afterward, and there is no induced chemical alteration. The only requirements are: (1) the artifact is clean and (2) a very thin carbon coat (approximately 0.00001-millimeters or 10-nanometers thick; for comparison, visible light has wavelengths from 400 to 700 nanometers) must be applied (for conductivity) and can be removed afterward.
Obsidian sourcing, or provenancing, can provide archaeologically useful information. For archaeological interpretation, it is an advantage to know precisely from where an artifact or its raw material originated. Information on the source of artifact material may be used to model trade networks and exchange spheres, and questions about the procurement and use of a material by past societies can be addressed. The mode of exchange by which the raw material or artifacts changed hands can also be explored. Trade implies contact, a source of cultural change as ideas are transmitted. In addition, the value of a material can be studied due to differences in the trade of commodities and prestige items. Issues that can be addressed extend beyond production and trade; matters of territory, access to resources, and technology can be delved into. The aim is to be able to make inferences about economic, political, and social structures of the cultures involved. Consequently, an artifact’s source, or its provenance, is as important as where it was unearthed.
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Latest News: Free Non-Destructive Obsidian Artifact Sourcing
The University of Minnesota's Electron Microprobe Laboratory has now alloted instrument time for obsidian sourcing using the MinOAN reference collection. This service is free of charge thanks to the lab, although a few conditions do exist. The obsidian artifacts must, of course, have originated in Turkey, Syria, Lebanon, Iraq, or elsewhere in the Near East for the MinOAN collection to be useful. Interested researchers should submit a proposal that includes the area, the approximate number of artifacts, research goals, etc. Other policies of the Electron Microprobe Laboratory will apply. Researchers at any level, from graduate students to faculty, and in any country are eligible and welcome to participate. Any researchers interested in participating or in further details are encouraged to contact Ellery Frahm.
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About the U of Mn Electron Microprobe Laboratory
The University of Minnesota Electron Microprobe Lab is a state-of-the-art facility for non-destructive chemical analysis of solids with a JEOL 8900 Electron Probe Microanalyzer. Our electron microprobe is capable of quantitatively measuring the abundance of all elements from Be to U with five fully automated wavelength-dispersive spectrometers (WDS) and an energy-dispersive spectrometer (EDS) for rapid analyses. The technique combines micron-scale chemical analyses with electron microscopy and is capable of large- and small-scale element mapping of specimens. With respect to geological research, our electron microprobe is often used for igneous, metamorphic, and experimental petrology as well as mineral investigations and geochronology. In addition to rocks and sediments, we have conducted analyses of metals, alloys, thin films, ceramics, composites, optical fibers, and other artificial materials. We welcome users from outside the University of Minnesota. We even have users who drive to our lab from Wisconsin, Iowa, Illinois, and the Dakotas. Users can either be trained to use the instrument or have their analyses done for them by lab personnel. Researchers found around the world have sent samples to our lab from as far away as Turkey and India.
Further information is available on-line at: http://probelab.geo.umn.edu
