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[1] Simple shear deformation experiments on three-phase, hydrous, haplogranitic magmas, composed of quartz crystals (24-65 vol.%), CO 2 -rich gas bubbles (9-12 vol.%) and melt in different proportions, were performed with a Paterson-type rock deformation apparatus. Strain rates from 5 Á 10 À6 s À1 to 4 Á 10 À3 s À1 were applied at temperatures between 723 and 1023 K and at pressure of 200 MPa. The results show that the three-phase suspension rheology is strongly strain rate dependent (non-Newtonian behavior). Two non-Newtonian regimes were observed: shear thinning (viscosity decreases with increasing strain rate) and shear thickening (viscosity increases with increasing strain rate). Shear thinning occurs in crystal-rich magmas (55-65 vol.% crystals; 9-10 vol.% bubbles) as a result of crystal size reduction and shear zoning. Shear thickening prevails in dilute suspensions (24 vol.% crystals; 12 vol.% bubbles), where bubble coalescence and outgassing dominate. At intermediate crystallinity (44 vol.% crystals; 12 vol.% bubbles) both shear thickening and thinning occur. Based on the microstructural observations using synchrotron radiation X-ray tomographic microscopy, bubbles can develop two different shapes: oblate at low temperature (<873 K) and prolate at high temperature (>873 K). These differences in shape are caused by different conditions of flow: unsteady flow, where the relaxation time of the bubbles is much longer than the timescale of deformation (oblate shapes); steady flow, where bubbles are in their equilibrium deformation state (prolate shapes). Three-phase magmas are characterized by a rheological behavior that is substantially different with respect to suspensions containing only crystals or only gas bubbles.Citation: Pistone, M., L. Caricchi, P. Ulmer, L. Burlini, P. Ardia, E. Reusser, F. Marone, and L. Arbaret (2012), Deformation experiments of bubble-and crystal-bearing magmas: Rheological and microstructural analysis,

New glass reference materials GSA‐1G, GSC‐1G, GSD‐1G and GSE‐1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 nm, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. In addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP‐MS, concentrations of fifty‐eight elements were determined with external calibration to the NIST SRM 610 glass reference material. Instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. In addition to NIST SRM 610 for external calibration, USGS BCR‐2G was used as a more closely matrix‐matched reference material in order to compare the effect of matrix‐matched and non matrix‐matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix‐matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix‐matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.

Garnet in metapelites from the Wo¨lz and Rappold Complexes of the Austroalpine basement east of the Tauern Window typically shows two distinct growth zones. A first garnet generation usually forms the cores of garnet porphyroblasts and is separated by a prominent microstructural and chemical discontinuity from a second garnet generation, which forms rims of variable width. Whereas the rims were formed during the Eo-Alpine metamorphic overprint, the garnet cores represent remnants of at least two pre-Eo-Alpine metamorphic events. The pressure and temperature estimates obtained from garnet isopleth thermobarometry applied to the first growth increments of the pre-Eo-Alpine garnet cores from the Wo¨lz and Rappold Complexes cluster into two distinct domains: (i) in the Wo¨lz Complex, incipient growth of the first-generation garnet occurred at 4 ± 0.5 kbar and 535 ± 20°C, (ii) in the Rappold Complex, incipient growth of the oldest garnet cores took place at 5.3 ± 0.3 kbar and 525 ± 15°C. The Eo-Alpine garnet generation started to grow at 6.5 ± 0.5 kbar and 540 ± 10°C. According to radiometric dating, the low-pressure garnet from the Wo¨lz complex was formed during a Permian metamorphic event. The first-generation garnet of the Rappold Complex is probably of Variscan age.

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