This trip is part of a 3 year NSF-funded project with Jim Gardner (Univ Texas) to understand how obsidian domes form, from small to big, from crystal-poor to crystal-rich. How fast do they erupt? How to they flow? Do they fragment? What is there connection to explosive eruptions?
Example of textures.
More ropy textures.
Logging the subplinian AD 1340 deposits (these contains CO2 rich obsidian that
documents non-equilibrium degassing).
Spherulites (why do these form? why don't they replace all the glass?).
Obsidian Dome.
Ben Andrews of the Smithsonian (middle) collecting oriented obsidian samples.
Collecting samples on North Coulee (notice people for scale).