Obsidian Hydration Study – Statewide
Obsidian Studies Program, Idaho Archaeological Society
- Grants: 2024 – Developing Obsidian Studies Research Strategy (OSRS)
Location: Statewide, most evaluations will occur on federally managed public land
Studies of obsidian (volcanic glass) play a significant role in the archaeology and anthropology of the Intermountain West. For almost 60 years, obsidian has been used to understand settlement/mobility, social interactions, and concepts of landscape amongst pre-contact peoples worldwide. This is due to the ability to tie obsidian artifacts to a specific area by analyzing the chemical composition of the obsidian through a process called geochemical sourcing. Surface analysis of obsidian artifacts also provides reliable dating of artifacts through a process called Obsidian Hydration Dating (OHD).
Obsidian is plentiful throughout Idaho, with fourteen documented sources. Several projects have successfully employed obsidian geochemical analysis; however, OHD has been minimally applied in Idaho due to a lack of data regarding two significant factors: structural water content within the obsidian and the temperature history of the artifacts in question. This project will design and initiate a program to create a public-access dataset to provide the necessary data for researchers/archaeologists to utilize OHD in Idaho.
The Idaho Archaeological Society, Idaho Heritage Trust, Bureau of Land Management, and Idaho State University will partner to address a large data gap in our understanding the timeline and behavior of pre-contact peoples in Idaho. Our project will also help facilitate the preservation and evaluation of pre-contact sites, and the implementation of the program also will help train future archaeologist in OHD to ensure that local Idaho facilities are available to assist in future studies.
The resources and cultural sites will date from 16,000 to 150 years ago and contribute to our understanding of the wide range of Native American history in the state of Idaho and surrounding regions. It is found in an archaeological context in the majority of sites in southern Idaho and most sites across the entire state and region. As an important and preferred material to create tools, obsidian was quarried, transported, and traded across the Intermountain West. Obsidian’s chemical properties allow it to be sourced and employed for dating. As a result, it allows for scientific analyses that can answer many important questions about past human behavior, such as mobility, trade, tool preferences, changing technologies, and perhaps, most importantly, chronology. Obsidian studies will allow archaeological practitioners, from Academics, to students, to cultural resource management specialists and tribes, to better analyze and understand the human history and archaeological record in the state of Idaho. While sourcing has been undertaken over the years, a concise source catalog has not been fully developed for Idaho, but a good foundation has been set by Idaho State University’s CAMAS lab. This will be the first large scale OHD endeavor in Idaho, which has never been applied in a systematic, replaceable, testable or successful manner in Idaho.
