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A statistically based re-evaluation of the evidence for a racemic abundance of quartz enantiomers suggests that, while this hypothesis is valid at the global scale, local deviations occur such that at any given location either l- or d-quartz may predominate. Thus, the hypothesis that the homochirality of life may have come about through interactions with a dominant quartz enantiomer at a particular location cannot be discounted. Keywords: Enantiomorphic, quartz, homochirality, statistics DOI: 10.2138/am.2009.3089

Quartz veins in high-pressure (HP) to ultrahigh-pressure (UHP) rocks are the products of fluid-rock interaction, and thus provide insight into fluid processes in subduction zones. In this paper, we report an integrated study of mineral inclusion, trace-element, U-Pb age, and Lu-Hf isotope compositions of hydrothermal zircon grains from a quartz vein within an UHP eclogite outcrop from the Hong'an area, western Dabie Mountains. These data are used to decipher the age, conditions of formation, and source of fluid for zircon formation during the exhumation of UHP rocks. Zircon grains from the vein have perfect euhedral shape, and show sector zoning or weak zoning, indicating that they precipitated from the aqueous fluid responsible for the vein formation. Raman spectroscopy analysis reveals that the zircon grains contain inclusions of garnet, omphacite, rutile, quartz, and [H.sub.2]O, implying that they crystallized from aqueous fluid under HP eclogite-facies conditions. The zircon grains show low Th/U and Lu/Hf ratios, nearly flat HREE patterns, absent Eu anomalies and low LREE contents. These characteristics are consistent with their precipitation in the presence of garnet and epidote, and absence of feldspar, and thus suggest that trace-element concentrations in hydrothermal zircon are controlled by co-precipitation of mineral assemblages. Crystallization temperatures of 670 to 712[degrees]C, which were calculated using the Ti content of zircon, are consistent with their formation under eclogite-facies conditions and may correspond to the temperature of the infiltrating fluid. The weighted mean [sup.206]Pb/[sup.238]U age of 224.7 [+ or -] 1.3 Ma is taken as the best estimate for the age of quartz-vein formation and records aqueous fluid flow during the early exhumation stage of UHP rocks. The zircon grains in the quartz-vein have Hf compositions similar to those in the host eclogite, which demonstrates isotopic equilibrium between fluid and rocks and that the fluid-rock ratio was likely low. Keywords: Hydrothermal zircon, trace element, Lu-Hf isotope, U-Pb age, HP-UHP metamorphism, quartz vein, western Dabie Mountains

Laser-ablation inductively coupled-plasma mass spectrometry (LA-ICPMS) is an established method of analyzing the elemental composition of individual fluid inclusions in minerals. While the method affords good spatial control of ablation pits, we have found that stray light from the UV (193 nm) laser may permanently modify the gas species in adjacent fluid inclusions. We have used Raman spectroscopy to analyze natural fluid inclusions in quartz before and after ablating test pits. New molecular species (CO, [H.sub.2], and [O.sub.2]) appeared in the vapor phases of inclusions near the pits, resulting in complex, disequilibrium gas mixtures (e.g., [CO.sub.2]-[CH.sub.4]-[H.sub.2]O-CO-[H.sub.2]-[O.sub.2]) and formation of iron oxyhydroxides in brine inclusions. Ablation for 40 s with a laser fluence of ~24 J/[cm.sup.2] on the sample produced the new gas species in inclusions at various distances up to 210 [micro]m from the pits, depending on pit diameter. We attribute the changes in gas speciation to molecular photodissociation induced by stray UV-laser light. We have no evidence that this artifact changes the bulk elemental composition or density of the affected inclusions. The problem for fluid inclusion analysis is that phase-transition temperatures (e.g., clathrate hydrate dissociation, partial homogenization of the carbonic phases, and total homogenization) are highly sensitive to the mixture of gas species present. This means that parameters such as gas compositions, bulk salinity, and minimum entrapment temperatures are likely to be misinterpreted if inclusions are analyzed by microthermometry or Raman spectroscopy in samples that have already undergone laser ablation. Keywords: Fluid inclusion, Raman spectroscopy, laser ablation ICP-MS, microthermometry, gas, speciation

Compositions of oxysalt, sulfosalt, seleniosalt, tellurisalt, and fluosalt minerals all follow the same generalizable patterns with regard to hardness or softness of cations, and with regard to ionic potential. For example, the hard [F.sup.1-] anion forms simple fluosalt minerals (fluoborates and fluosilicates) with hard cations. The relatively hard [O.sup.2-] anion forms simple oxysalts (e.g., sulfates and arsenates) largely with hard to intermediate cations. On the other hand, the softer [S.sup.2-] anion forms sulfosalt minerals almost entirely with intermediate to soft cations, and the still softer anions [Se.sup.2-] and [Te.sup.2-] form seleniosalt and tellurisalt minerals with an even more predominately soft suite of cations. Thus, across all these classes of minerals, harder anions generally form minerals with harder cations, and softer anions form minerals with softer cations. The compositions of simple oxysalt minerals of one inter-radical cation vary greatly, but they do not include minerals in which both the inter-radical cation and intra-radical cation (e.g., [Ca.sup.2+] and [S.sup.6+] in CaS[O.sub.4]) have high ionic potential. Their compositions thus reach, but do not exceed, a limit on a plot of the ionic potential of cations in these minerals. The same general relationship, wherein no simple minerals contain both inter-radical and intra-radical cations of high ionic potential, also exists among sulfosalts, seleniosalts, tellurisalts, and fluosalts. These limits of ionic potential of cations are greatest in oxysalts and progressively less in fluosalts, sulfosalts, seleniosalts, and tellurisalts. The limits thus decrease, both through the 2- anions and across the hard anions, from more negative ionic potential of the anion to less so, seemingly because anions of less negative ionic potential have lesser capability to shield cations from each other and thereby preclude cation-cation repulsion. Among the simple oxysalts of one inter-radical cation, three minerals near the oxysalt limit form less commonly, or with greater inhibition, than one might expect. For example, thermodynamic calculations indicate that magnesite should precipitate abundantly from seawater, but it does not instead, in low-temperature systems [Mg.sup.2+] only forms simple carbonate minerals with a cation of lesser ionic potential ([Ca.sup.2+]). Similarly, the chemistry of Earth's crust suggests that [(Al,[Fe.sup.3+]).sub.2][(S[O.sub.4]).sub.3] would be a common mineral, but instead analogous hydrous minerals with additional cations of lesser ionic potential are common. Finally, Si[O.sub.2] minerals crystallize at distinctly low temperatures in magmatic systems, and they either fail to nucleate or precipitate as a hydrous disordered mineral in many low-temperature systems. In all three cases, cation-cation repulsion seemingly inhibits formation of what might otherwise be more common or more readily forming minerals. Keywords: Geochemistry, systematic mineralogy, sulfosalts, quartz, magnesite, alunite, millosevichite, cations

Force frequency coefficients of a Y-cut langanite (LGN) resonator and a Y-cut langatate (LGT) resonator as a function of the azimuthal angle is measured. The maximum magnitudes of the coefficients of the LGN and the LGT are five and seven times smaller than that of stress compensated cut (SC-cut) quartz.

Force frequency coefficients of a Y-cut langanite (LGN) resonator and a Y-cut langatate (LGT) resonator as a function of the azimuthal angle is measured. The maximum magnitudes of the coefficients of the LGN and the LGT are five and seven times smaller than that of stress compensated cut (SC-cut) quartz.

About 1000 zircon grains from a diamondiferous quartzofeldspathic rock of the Saxonian Erzgebirge were investigated for inclusions using optical microscopy and confocal laser-Raman spectroscopy. Cathodoluminescence imagery was applied to characterize the growth zone of zircon where the inclusions occurred. The most abundant inclusion minerals are microdiamonds. Coesite was not detected. However, garnet and jadeite occur as rare inclusions in zircon cores where diamonds are lacking. Jadeite was detected for the first time in quartzofeldspathic rocks from the crystalline complex of the Erzgebirge. The compositions of the pristine garnets in the zircons are similar to those of core areas of millimeter-sized garnets but the original garnet composition of the early metamorphic stage is only preserved in zircon. Intracrystalline diffusion at temperatures as high as 1000 [degrees]C resulted, for instance, in higher Ti concentrations in garnet cores compared with garnet enclosed in zircon. Rutile, quartz, and the compositions of jadeite and garnet inclusions in zircon and of phengite inclusions in cores of large garnets were applied for geothermobarometry. The results, related to an early metamorphic stage, are 650[degrees]C and 18 kbar, which represent conditions at the base of a thickened continental crust before deeper subduction.

The structure of the microporous silica polymorph silicalite was stabilized well beyond the stability range of tetrahedrally coordinated Si[O.sub.2] and the metastability range of low-pressure silica polymorphs such as quartz and cristobalite at room temperature via the incorporation of carbon dioxide or argon. The insertion of guest species deactivates the normal compression and pressure-induced amorphization mechanisms in the silicate material was observed to impede the softening of low-energy vibrations, amorphization, and the eventual increase in silicon coordination up to at least 25 GPa.

A model is developed to describe experimental data of mechanical losses in a a round quartz plate with the diameter 7.48 cm and the thickness 1.2 cm at temperatures 5-25 K in the range of eigenfrequencies 11-300 kHz. The model is able to account for both the contribution of thermoelastic losses and the contribution due to the interaction of the acoustic wave with thermal phonons (Akhieser damping).

A newly developed Monte Carlo (MC) algorithm is designed for studying the complex interplay of dissolution and precipitation reactions on mineral surface. The method is used for understanding the role of the local arrangement of reactive sites and surface topography in the surface evolution during dissolution and the stepwise dissolution has resembled the steady-state dissolution of the quartz-water system.

The observation of coupled magnetostatic-electromagnetic oscillations over 60-75 GHz in strontium hexaferrite-quartz structures is reported. Estimated Q-factor for the coupled modes is found to show significant and unique variation with the bias magnetic field in the mode repulsion region.