ObsidianSession

Obsidian from Magma to Artifact:

Geological and Archaeological Perspectives

Geological Society of America 2009 Annual Meeting • Portland, OR • October 18-21

Main Page & CV Obsidian Sourcing Electron Microprobe Analysis in Archaeology GeoArchSci Blog

Session: Obsidian from Magma to Artifact: Geological and Archaeological Perspectives - Topical Session #157 (Oral)

Short Description: This session brings together archaeologists and geoscientists from diverse fields -- geochemistry, igneous petrology, volcanology, geomorphology, and more -- to present on the topic of obsidian research, from magma formation and eruption to dating and sourcing artifacts.

Sponsors: Archaeological Geology Division; Quaternary Geology and Geomorphology Division; Geochemical Society

Session Organizers:

Ellery Frahm - email - website
Senior Research Fellow, Department of Geology & Geophysics
Doctoral Candidate, Department of Anthropology
University of Minnesota - Twin Cities

Joshua Feinberg - email - website
Assistant Professor, Department of Geology & Geophysics
Associate Director, Institute for Rock Magnetism
University of Minnesota - Twin Cities

Session Description and Scope:

Obsidian is studied by archaeologists and geoscientists from diverse fields -- geochemistry, igneous and experimental petrology, volcanology, geomorphology, Quaternary geology, and more. This session aims to highlight complementary obsidian research in these different disciplines, disseminate findings among scientists who study similar materials, and hopefully, forge new collaborations and research directions. The anticipated breadth of this session is reflected in its co-sponsors: the Archaeological Geology Division, the Quaternary Geology and Geomorphology Division, and the Geochemical Society. Additionally, the host state of GSA 2009, Oregon, has much obsidian, including the well-known outcrops at Glass Butte and Newberry Crater. Thus, it is only fitting that GSA 2009 should have an obsidian-focused session. We hope to attract both archaeologists and geoscientists to present a wide range of topics involving obsidian.

Potential topics of geological focus include: volatile content and diffusion, magma differentiation and mixing processes, subduction and shallow-mantle volcanism, shear and magma dynamics, microlite orientation and size distributions, viscosity, flow banding and obsidian textures, petrochemical and physical features, oceanic versus continental obsidians, geochemical gradients and zoning within obsidian, lava dome development, devitrification processes, experimental rhyolitic melts, fluorite stability, alteration, and geomagnetism.

Potential topics of archaeological focus include: stone tool production, 40Ar/39Ar dating, fission-track dating, hydration rim dating, geochemical artifact sourcing and selecting appropriate analytical techniques, obsidian trade and exchange mechanisms, outcrop surveys, material "quality" for tools, and prestige and perceived value of obsidian.

If you have any questions or comments about the session, please feel free to contact the session organizers.

List of Participants:

Invited Keynote Speakers

Tristan Carter - website
Professor, Department of Anthropology
McMaster Univeristy

Michael Manga - webpage
Professor, Department of Earth and Planetary Science
University of California-Berkeley

M. Steven Shackley - webpage
Professor and Director, Geoarchaeological XRF Laboratory
University of California-Berkeley

Submitted Talks

See the GSA website for a full list of the participants in the oral session and complementary poster session.

FAQ for GSA 2009:

1) Where is the official conference website?

Please visit the Geological Society of America 2009 Annual Meeting website for the latest information.

2) How long is each talk?

The timeslot for each talk is 15 minutes. Please plan your talk to be about 12 minutes long, which allows a few minutes for questions and transitions between speakers.

3) Can non-GSA-members attend the conference and participate in the session?

Yes, non-members can attend the conference and participate in the session, but the registration fees are a bit more. For most membership types, it is actually cheaper to join GSA first and then get the member fee.

4) Are there instructions for presenters?

Please the GSA website for their instructions to presenters.

Images from left to right: volcanic eruption and magma chamber inset (Gary Hink), flow banding of microlites in obsidian from Turkey (Ellery Frahm), vesicles within Lipari obsidian (Stromboli online website by Alean, Carniel, and Fulle), old postcard of Obsidian Cliff in Yellowstone National Park (unknown artist), and obsidian blades from an archaeological site in Syria (Ellery Frahm).