tidal triggering mechanism, ibecause a similar process appears to trigger terrestrial volcanic eruptions (4), and perhaps earthquakes as well (5). The terrestrial situation is somewhat obscured, however, because of the complicating loading effects of oceanic and atmospheric tides, ocean currents, and atmospheric circulation. The moon has provided another clear, albeit luxurious, view of the ear...

The bifacially-flaked stemmed obsidian artifacts from Easter Island -known as mata’a -vary greatly in terms of the shape and form of their stems. The stem variability appears to be largely stylistic in nature as its variation does not affect the function of the tool and thus is free to change. Since performance is not a factor in structuring variation , patterns of similarity across stylistic c...

Cristobalite and tridymite in andesite and obsidian exhibit bright blue emissions in color cathodoluminescence (CL) images. CL spectra of cristobalite and tridymite show emission bands at 400 and 430 nm, respectively. Their CL intensity decreases with an increase in the electron irradiation time, similar to the short-lived blue luminescence reported in hydrothermal quartz. The reduction rate of...

Geobacillus sp. Y412MC52 was isolated from Obsidian Hot Spring, Yellowstone National Park, Montana, USA under permit from the National Park Service. The genome was sequenced, assembled, and annotated by the DOE Joint Genome Institute and deposited at the NCBI in December 2011 (CP002835). Based on 16S rRNA genes and average nucleotide identity, Geobacillus sp. Y412MC52 and the related Geobacillu...

Spherulites are spherical clusters of radiating crystals that occur naturally in rhyolitic obsidian. The growth of spherulites requires diffusion and uptake of crystal forming components from the host rhyolite melt or glass, and rejection of non-crystal forming components from the crystallizing region. Water concentration profiles measured by synchrotron-source Fourier transform spectroscopy re...