Degassing processes occurring within silicic magma, such as bubble growth, resorption, the welding of magma fragments, and open-system gas loss are crucial in control volcanic eruption lava emplacement, yet their details still debated. To examine possibility that these degassing recorded glass heterogeneous Cl distribution patterns, we experimentally simulated by heating rhyolitic obsidian anal...

The San Miguel de Allende graben, Guanajuato, Mexico, contains numerous rhyolitic volcanic ash beds. Electron microprobe and x-ray fluorescence analyses of glass shards from 14 localities, combined with mineralogic, stratigraphic, radiometric, and paleomagnetic data, allow us to correlate the ash beds (and the intervening sedimentary strata and fossils), understand the timing of volcanism, date...

Syrtis Major is an old, low relief volcanic plateau near the equatorial regions of Mars. It is a persistent low-albedo feature on the planet and is thought o contain a high abundance of exposed bedrock and/or locally derived surface material and debris. Spatially resolved variations in surface spectral properties, and therefore composition, are investigated with data from the Imaging Spectromet...

A calibrated radiocarbon database of late Quaternary volcanic eruptions R. U. Bryson, R. A. Bryson, and A. Ruter National Park Service, Mojave National Preserve, 2701 Barstow Road, Barstow, CA 92311, USA Center for Climatic Research, University of Wisconsin-Madison, 1225 W. Dayton St., Madison, WI 53706, USA Received: 24 May 2006 – Accepted: 17 July 2006 – Published: 25 July 2006 Correspondence...

We have completed laboratory experiments and thermochemical equilibrium models to investigate secondary mineral formation under conditions akin to volcanic, hydrothermal acid-sulfate weathering systems. Our research used the basaltic mineralogy at Cerro Negro Volcano, Nicaragua, characterized by plagioclase, pyroxene, olivine, and volcanic glass. These individual minerals and whole-rock field s...

[1] In the Inner Basin of the Columbia Hills, Gusev Crater is Home Plate, an 80 m platform of layered clastic rocks of the Barnhill class with microscopic and macroscopic textures, including a bomb sag, suggestive of a phreatomagmatic origin. We present data acquired by the Spirit Mars Exploration Rover by Alpha Particle X-Ray Spectrometer (APXS), Mössbauer Spectrometer, Miniature Thermal Emiss...