Timescales of spherulite crystallization in obsidian inferred from water concentration profiles
نویسندگان
چکیده
منابع مشابه
ERRATUM Diffusion-controlled spherulite growth in obsidian inferred from H2O concentration profiles
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...
متن کاملDiffusion-controlled spherulite growth in obsidian inferred from H2O concentration profiles
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...
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[1] Explosivity of rhyolite domes depends on bubble nucleation and growth. To understand these processes, we measure millimeter-scale variations in H2O by synchrotron Fourier transform infrared (FTIR) spectromicroscopy on interlayered obsidian-pumice samples. The H2O contents of all samples are above the 1-atm solubility value ( 0.10wt.%) and decrease systematically towards vesicular zones, ind...
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Rhyolitic obsidians from Krafla volcano, Iceland, record the interaction between mobile hydrous species liberated during crystal growth and the reduction of ferric iron in the silicate melt. We performed synchrotron μ-FTIR and μ-XANES measurements along a transect extending from a spherulite into optically distinct colorless and brown glass zones. Measurements show that the colorless glass is e...
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The flow of obsidian lava leads to crystal alignments that reflect both the accumulated strain and the type of flow across the surface. Microlite preferred orientations are used to investigate the emplacement dynamics, strain history, and structural evolution of Obsidian Dome, eastern California. Measurements of three-dimensional microlite trend and plunge in samples from the near-vent region, ...
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ژورنال
عنوان ژورنال: American Mineralogist
سال: 2008
ISSN: 0003-004X
DOI: 10.2138/am.2008.2904