The geology, geochemistry, and geographic distribution of southern Idaho obsidian

Technical Report · Sat Jul 01 04:00:00 EDT 2023

DOI:https://doi.org/10.2172/2352670· OSTI ID:2352670

Pink, Jeremias W. ^[1]

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1. Idaho National Laboratory (INL), Idaho Falls, ID (United States)

The Snake River Plain Volcanic Province of Southern Idaho is host to an abundance of pyroclastic obsidian deposits that constitute the principal lithic raw material utilized by Native Americans of the region throughout the Precontact Period. Archaeologists have long looked to obsidian as a source of information on past patterns of raw material selection, landscape use, and mobility through geochemical analysis of obsidian artifacts and lithic raw materials. Formation of the Snake River Plain through cataclysmic “super-eruptions” of the Yellowstone hotspot, however, presents one of the most complex and poorly understood obsidian source-scapes of North America. To clarify the geographic distribution of Southern Idaho obsidian source groups, the INL CRMO has compiled a comprehensive reference library of geologic obsidian from 138 source locales distributed across the southern half of the state. In this report, we define 28 geochemically distinct obsidian source groups that occur at these deposits through X-ray Fluorescence spectrometry and contextualize the geographic distribution of each source group relative to the history of silicic magmatism on the Snake River Plain. This research facilitates ongoing investigations at the INL CRMO into patterns of obsidian procurement, conveyance, and exchange in Southern Idaho throughout the Precontact Period.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 2352670
• Report Number(s): INL/RPT--23-73575-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
58 GEOSCIENCES
Archaeology
Idaho
Lithic Landscape
Obsidian
Obsidian Sourcescape
Provenance
X-Ray Fluorescence
XRF