Near-infrared and Visible Light Microthermometry of Fluid Inclusions in Sphalerite from a Possible Southeast Extension of the Toyoha Polymetallic Deposit, Japan   总被引：2，自引：0，他引：2  

Toru Shimizu    Masahiro Aoki  Taro Kabashima 《Resource Geology》2003,53(2):115-126

Abstract. Near-infrared (NIR) and visible light microthermometry was applied to the fluid inclusions in sphalerite from a possible southeast extension of the Toyoha polymetallic deposit. Sphalerite occurs as euhedral-subhedral crystals or collo-form aggregates with a variety of color, which contain a well-developed growth banding. Combined with morphological observations, fluid inclusions in dark-colored sphalerite were examined using a near-infrared light microscopic technique, whereas those in light-colored sphalerite and quartz were examined by a conventional visible light microscopy.
Salinities of fluid inclusions in dark-colored sphalerite have a wide variation (1.0–10.3 wt % NaCl equiv.) compared to that in light-colored sphalerite and quartz (0.0–3.4 wt % NaCl equiv.). These variations suggest that the conventional microthermometric data from light-colored sphalerite and quartz were inadequate to interpret the ore formation process. Dark-colored colloform sphalerite and a dark core of subhedral sphalerite formed from high-salinity fluids (6.5–10.3 wt % NaCl equiv.) under highly supersaturated conditions with respect to sphalerite.
The NIR and visible light microthermometry of fluid inclusions in sphalerite combined with its morphological observations is an invaluable method to infer the formation conditions of sphalerite. The NIR and visible light microthermometry is useful to reveal how the nature of ore fluids changed with time.  相似文献   

The use of microstructures for discriminating turbiditic and hemipelagic muds and mudstones          下载免费PDF全文

Yoshihiro Kase  Makoto Ito  Ken Ikehara  Shigeru Takizawa 《Sedimentology》2016,63(7):2066-2086

The microstructures of turbiditic and hemipelagic muds and mudstones were investigated using a scanning electron microscope to determine whether there are microstructural features that can differentiate turbiditic from hemipelagic sedimentary processes. Both types of muddy deposits are, in general, characterized by randomly‐oriented clay particles. However, turbiditic muds and mudstones also characteristically contain aggregates of ‘edge‐to‐face’ contacts between clay particles with long‐axis lengths of up to 30 μm. Based on observations of the clay fabric of the experimentally‐formed muds settled from previously agitated muddy fluids, these types of aggregates, hereafter referred to as ‘aggregates of clay particles’, are interpreted as having been formed by the collision of component flocs in turbulent fluids. Furthermore, some aggregates of clay particles have ‘face‐to‐face’ contacts between clay particles; this is similar to face‐to‐face aggregates characteristically developed in fluid‐mud deposits that are commonly recognized only in turbiditic mudstones, indicating the possibility of a final stage of deposition under highly‐dense conditions, such as temporary fluid muds. In conjunction with earlier proposed lithofacies‐based and ichnofacies‐based criteria, aggregates of clay particles should be useful for the differentiation of turbiditic and hemipelagic muddy deposits, particularly with limited volumes of non‐oriented samples from deep‐water successions.  相似文献   

Determination of Cadmium and Lead in Seventy-seven Geological Reference Samples by Atomic Absorption Spectrometry     

Shigeru Terashima 《Geostandards and Geoanalytical Research》1984,8(1):13-16

The cadmium and lead contents of seventy-seven geological reference samples have been determined by atomic absorption spectrometry using an air-acetylene flame or a carbon tube atomizer, after extraction of cadmium and lead as iodides with methylisobutylketone (MIBK). The agreement between the present results and published data is generally good.  相似文献   

Determination of Arsenic and Antimony in Eighty-Five Geochemical Reference Samples by Automated Hydride Generation and Electrothermal Atomic Absorption Spectrometry     

Shigeru TERASHIMA 《Geostandards and Geoanalytical Research》1986,10(2):127-130

The arsenic and antimony contents of 85 geochemical reference samples have been determined by atomic absorption spectrometry with hydride generation and heated quartz cell atomizer. The sample is decomposed with a mixture of perchloric, nitric and hydrofluoric acids and potassium permanganate solution; interferences are eliminated by addition of potassium iodide, aluminium chloride and ascorbic acid. The agreement between the present results and published data is fairly good.  相似文献   

Determination of Beryllium in Eighty Geological Reference Samples by Atomic Absorption Spectrometry     

Shigeru TERASHIMA 《Geostandards and Geoanalytical Research》1983,7(2):295-299

The beryllium content of eighty geological reference samples has been determined by atomic absorption spectrometry using a nitrous oxide-acetylene flame or a carbon tube atomizer, after extraction of beryllium as acetylacetonate with methylisobutylketone (MIBK). The agreement between the present results and published data is generally good.  相似文献   

Effects of irrigation on CO₂ and CH₄ fluxes from Mongolian steppe soil     

Shigeru Mariko  Tadaaki Urano 《Journal of Hydrology》2007,333(1):118-123

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Strain and tilt changes measured during a water injection experiment at the Nojima Fault zone, Japan   总被引：2，自引：0，他引：2  

Kunio Fujimori  Hiroshi Ishii  Atsushi Mukai  Shigeru Nakao  Shigeo Matsumoto  Yasuhiro Hirata 《Island Arc》2001,10(3-4):228-234

Abstract In order to make geophysical and geological investigations of the Nojima Fault on Awaji Island, Japan, three boreholes measuring 1800 m, 800 m and 500 m deep were drilled into the fault zone. The fault is one of the seismic source faults of the 1995 Hyogo-ken Nanbu earthquake of M 7.2. A new multicomponent borehole instrument was installed at the bottom of the 800 m borehole and continuous observations of crustal strain and tilt have been made using this instrument since May 1996. A high-pressure water injection experiment within the 1800 m borehole was done in February and March 1997 to study the geophysical response, behavior, permeability, and other aspects of the fault zone. The injection site was located approximately 140 m horizontally and 800 m vertically from the instrument. Associated with the water injection, contraction of approximately 0.7 × 10⁻⁷ str (almost parallel to the fault) and tilt of approximately 1 × 10^-7 rad in the sense of upheaval toward the injection site were observed. In addition to these controlled experiments, the strainmeter and tiltmeter also recorded daily variations. We interpret strain and tilt changes to be related to groundwater discharge and increased ultra-micro seismicity induced by the injected water.  相似文献   

Andesine megacrysts in alkali basalts from Japan     

Ken-ichiro Aoki 《Contributions to Mineralogy and Petrology》1970,25(4):284-288

Andesine megacrysts up to 3 cm in size occur sporadically in certain alkali basalts and allied mafic rocks in southwestern Japan. They are sometimes accompanied by megacrysts of mafic minerals and ultramafic and mafic inclusions. Nine andesines have been chemically analysed.From the petrography and chemistry and the results of high pressure experimental work, it is suggested that andesine megacrysts crystallized from alkali basalt magma under dry conditions at a depth of about 30 to 60 km.  相似文献   

Evolution of Planetesimal Velocities Based on Three-Body Orbital Integrations and Growth of Protoplanets     

Keiji OhtsukiGlen R. Stewart  Shigeru Ida 《Icarus》2002,155(2):436-453

We obtain the viscous stirring and dynamical friction rates of planetesimals with a Rayleigh distribution of eccentricities and inclinations, using three-body orbital integration and the procedure described by Ohtsuki (1999, Icarus137, 152), who evaluated these rates for ring particles. We find that these rates based on orbital integrations agree quite well with the analytic results of Stewart and Ida (2000, Icarus 143, 28) in high-velocity cases. In low-velocity cases where Kepler shear dominates the relative velocity, however, the three-body calculations show significant deviation from the formulas of Stewart and Ida, who did not investigate the rates for low velocities in detail but just presented a simple interpolation formula between their high-velocity formula and the numerical results for circular orbits. We calculate evolution of root mean square eccentricities and inclinations using the above stirring rates based on orbital integrations, and find excellent agreement with N-body simulations for both one- and two-component systems, even in the low-velocity cases. We derive semi-analytic formulas for the stirring and dynamical friction rates based on our numerical results, and confirm that they reproduce the results of N-body simulations with sufficient accuracy. Using these formulas, we calculate equilibrium velocities of planetesimals with given size distributions. At a stage before the onset of runaway growth of large bodies, the velocity distribution calculated by our new formulas are found to agree quite well with those obtained by using the formulas of Stewart and Ida or Wetherill and Stewart (1993, Icarus106, 190). However, at later stages, we find that the inclinations of small collisional fragments calculated by our new formulas can be much smaller than those calculated by the previously obtained formulas, so that they are more easily accreted by larger bodies in our case. The results essentially support the previous results such as runaway growth of protoplanets, but they could enhance their growth rate by 10-30% after early runaway growth, where those fragments with low random velocities can significantly contribute to rapid growth of runaway bodies.  相似文献   

Preparation of Two New GSJ Geochemical Reference Materials: Basalt JB-1b and Coal Fly Ash JCFA-1   总被引：1，自引：0，他引：1  

Shigeru Terashima  Masahiro Taniguchi  Masumi Mikoshiba  Noboru Imai 《Geostandards and Geoanalytical Research》1998,22(1):113-117

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