Microtephrochronology is a stratigraphic dating method used by archaeologists and Quaternary scientists involving the location and characterisation of volcanic glass particles present in soils and sediments in sizes and amounts invisible to the unaided eye (e.g., Alloway et al. 2007; Turney and Lowe 2001). Accurate determination of the presence or absence of volcanic glass shards in a soil or s...

The 18-km-diameter El’gygytgyn crater is located on the Chukotka peninsula, northeastern Russia. It represents the only currently known impact structure formed in siliceous volcanics, including tuffs. The impact melt rocks and target rocks provide an excellent opportunity to study shock metamorphism of volcanic rocks. The shockinduced changes observed in porphyritic volcanic rocks from El’gygyt...

Volcanic ash is fragments of magma, and consists of minerals and volcanic glass. These materials in the ash can provide important information on the nature of the magma, because chemical compositions of magma usually show distinct features in each volcano, and because assemblages and compositions of minerals reflect their host melt. Using assemblages and chemical compositions of minerals and gl...

Volcanic ash particles can be remelted by the high temperatures induced in volcanic lightning discharges. The molten particles can round under surface tension then quench to produce glass spheres. Melting and rounding timescales for volcanic materials are strongly dependent on heating duration and peak temperature and are shorter for small particles than for large particles. Therefore, the size...

1 The diversity of microbial communities inhabiting two terrestrial volcanic glasses of 2 contrasting mineralogy and age was characterised. Basaltic glass from a <0.8 Ma 3 hyaloclastite deposit (Valafell) harbored a more diverse Bacteria community than the 4 younger rhyolitic glass from ~150-300AD (Dόmadalshraun lava flow). Actinobacteria 5 dominated 16S rRNA gene clone libraries from both site...

Introduction: Volcanism is the primary process in the solar system that creates the surfaces of the terrestrial planetary bodies. Volcanoes and volcanic surface units provide information about the geologic history of these bodies, which reflects the unique thermal and chemical evolution of each. Remote sensing provides an effective means to study these volcanic surface units in a quantitative w...

Volcanic glass is deposited with trace amounts (0.1–0.6 wt.%) of undegassed magmatic water dissolved in the glass. After deposition, meteoric water penetrates into the glass structure mostly as molecular H2O. Due to the lower dD (‰) values of non-tropical meteoric waters and the 30‰ offset between volcanic glass and environmental water during hydration, secondary water imparts lighter hydrogen ...

Phillipsite has formecl from volcanic glass in saline, alkaline lakes both saturated and undersaturated with respect to gaylussite and trona. It has also formed from volcanic glass in saiine, alkaline soils of Olduvai Gorge, Tanganyika. Phillipsite occurs both as lath,shaped and as equant crystals, which are commonly zoned lvith refractive indices ranging between 1.438 and 1.490. Molecular SiOz...

The compositional record of the AND-2A drillcore is examined using petrological, sedimentological, volcanological and geochemical analysis of clasts, sediments and pore waters. Preliminary investigations of basement clasts (granitoids and metasediments) indicate both local and distal sources corresponding to variable ice-volume and ice-flow directions. Low abundance of sedimentary clasts (e.g.,...

Observed enrichments of N (and the δ15N of this N) in volcanic glasses altered on Earth's modern and ancient seafloor are relevant in considerations of modern global N subduction fluxes and ancient life on Earth, and similarly altered glasses on Mars and other extraterrestrial bodies could serve as valuable tracers of biogeochemical processes. Palagonitized glasses and whole-rock samples of vol...