High temperature-pressure cell for micro-IR and Raman spectroscopy have been developed to investigate molecular structure of water under sub- and supercritical conditions. The maximum temperature and pressure of the cell were 400 °C and 50 MPa, and artificial yellow diamond was installed as a transparent window of the cell. In case of micro-IR spectroscopic measurement, incident beam was illuminated to the high temperature-pressure cell using the Cassegrainian mirror, and reflected light was analyzed by FTIR system. In case of micro-Raman spectroscopic measurement, an incident laser beam (Nd:YAG laser: 532 nm) was irradiated into the cell through standard optical lens. As a result of infrared spectroscopic measurements of water, the broad peak around 3360 cm-1 of infrared spectra, attributed to OH stretching vibration mode of water molecular, was observed at room temperature and pressure. The peak position shifted to higher wavenumber with increasing temperature and shifted to lower wavenumber with increasing pressure. Continuous shift of the OH stretching vibration mode of water molecule was detected by using newly designed high temperature-pressure cell. The peak position and behavior of peak shift of interfacial water were affected by substrate. In case of interfacial water on artificial quartz, the peak position shifted to higher wavenumber with increasing temperature, however no obvious change was observed with as a function of pressure. It was possible to measure IR and Raman spectra under supercritical condition by using high temperature-pressure cell, and characteristics of molecular structure of interfacial water revealed by IR spectra was changed by environmental conditions such as temperature, pressure and substrate.
Experiments on the simultaneous partitioning of divalent metal ions were carried out in the system K2Mg6Al2Si6O20(OH)4 (phlogopite) − KCl - (Ni2+,Mg2+,Co2+,Zn2+,Fe2+,Mn2+,Ca2+,Sr2+) Cl2 - H2O in the temperature range of 500 to 800 °C at 100 MPa, using the pressure vessel of a cold seal type. The partition coefficient KPN (Phl) for the ion exchange reaction between phlogopite (Phl) and aqueous chloride solution (aq) can be expressed as follows:
where Me designates divalent metal ion, m: molality, and Xi: mole fraction of end-member i in biotite solid solution. The partition coefficient - ionic radius (PC-IR) curve marks a peak between Mg2+ and Fe2+. Zn2+ shows the same negative anomaly in the partition coefficients as observed in other minerals with 6-fold sites. Co2+ also represents such a negative anomaly as was previously found in tremolite and hedenbergite. Based on the previous and present experimental results, it is considered that the anomaly of Co2+ may be related with polymerization of Si tetrahedra.
Garronite occurs as radiating aggregates of minute fibrous crystals in amygdales of altered trachybasalt from Kuniga, Oki Islands, Shimane Prefecture, Japan. The mean chemical composition by EDS analysis leads to the empirical formula, (Na1.15K0.15)Σ1.30Ca2.28[Al5.88Si10.06]O32·13.60H2O on the basis of O=32 in anhydrous part and H2O by difference. The unit cell parameters calculated from the X-ray powder diffraction data are a = 9.961 (3), b = 10.178 (4), c = 9.958 (4) (Å) and β = 90.020 (1) (°) with a monoclinic cell.
Mt. Kohide (Nakatsugawa City, Gifu Prefecture) is located ∼ 7 km north of the Atera fault. A partial collapse of the northwestern flank of Mt. Kohide has exposed a 5-m-wide dyke-like conduit ∼ 15-30 m beneath the extrusive rhyolite lava that was fed by it. The rocks of the extrusive lava and the feeder are nearly aphyric (< 0.5 vol% phenocrysts), biotite-rhyolite (∼ 73 wt% whole-rock SiO2). The extrusive lava yields a K-Ar age of 23.01 ± 0.36 Ma. Within the measurement errors, this age coincides with the previously determined K-Ar ages of biotite-rhyolite dykes intruded along the Atera fault (23-22 Ma) and the rhyolitic welded tuff of the Hachiya formation (∼ 40 km southwest of Mt. Kohide; 22 Ma) as well as the K-Ar and fission track ages of the rift-type alkalic moonstone rhyolites from the Hokuriku area (25-22 Ma). This suggests that rhyolitic volcanism occurred contemporaneously in central Japan between the Late Oligocene and Early Miocene.