[1] With the prevalence of glass and molten silicates in volcanic environments, and the important role of surface emissivity in thermal infrared (TIR) measurements, it is imperative to characterize accurately the spectral features associated with silicate glasses and melts. A microfurnace has been developed specifically for use with a laboratory Fourier transform infrared (FTIR) spectrometer to...

We present a chemical model of magma degassing based on nine volatile species part of S-O-H-C-Fe-bearing rhyolitic melts. It is based on equilibrium, closed-system degassing, and does not take in account the crystallization of mineral phases. For given initial conditions at depth, the model calculates the gas composition as pressure decreases, as well as physical variables controlling conduit f...

the gandy gold-base metal deposit is located in tertiary torud-chahshirin volcano-plutonic range, north of central iran. various styles of gold mineralization occur throughout the range. mineralization at gandy occurs in close spatial relation with rhyolitic domes in a caldera setting in a series of narrow brecciated veins. two mineralogically and spatially different argillic alterations have a...

Tephra preserved in sediments form useful isochronous marker layers, linking disparate geological, palaeoenvironmental and archaeological records. The application of tephrochronology is greatly enhanced through the detection macroscopically invisible tephra (cryptotephra). Here, we identify two discrete cryptotephra Samoan lake sediments, first identification region outside New Zealand. Geochem...