Zinc sulfide synthesized in six systems (Zn-S-H₂O, ZnO-S-H₂O, ZnCl₂-S-H₂O, ZnCl₂-S-CaCO₃-H₂O, ZnCl₂-S-Na₂CO₃-H₃O, ZnCl₂-Na₂S-H₂O) of aqueous solution at 250°C and 300°C were exmained by the x-ray diffraction method. Wurtzite and sphalerite formed simultaneously in the system ZnCl₂-S-Na₂CO₃-H₂O; minerals synthesized in other five systems were all sphalerite. The chemical species resulted from the chemical reactions in each system certainly regulate the environmental conditions and, therefore, play an important role in the mineral syntheses. Wurtzite is associated with sulfate (HSO₄^-, SO₄^--) as dominant sulfur species produced in the system, where the higher the pH value of the solution, the more wurtzite is produced. On the contrary, sphalerite forms in the sulfuric and hydrochloric acid solutions containing dominantly hydrogen sulfide and native sulfur.

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Direct measurements of hydrogen sulfide released from tidal flats were made on six diverse seashores of Mikawa Bay, Japan, from November 1979 to October 1980. The concentration has been determined in situ by sulfide-ion electrode method, with a detectability to be approximately 0.1 μ mol/1 (0.1μ mol H₂S/m²/hr). The hydrogen sulfide emission rates are detected to be only about 1 to 2 μ mol H₂S/ m²/hr at organic-rich, black and muddy tidal flats, except one site, and less than 0.1 μ mol H₂S/m²/hr at organic-poor, white and sandy tidal flats. We estimate the amount of hydrogen sulfide yearly released from tidal flats in Japan to be about 90 tons S based on the emission rates measured in this study. This value is far smaller than the values, some million tons of sulfur, evaluated indirectly by previous investigations. The atmospheric sulfur over Japan is supplied chiefly by man-made sulfur dioxide, and hydrogen sulfide released from tidal flats is negligible.

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The ³⁴S/³²S ratios of coexisting sphalerite and galena from Taishu, Toyoha and Kamioka Pb-Zn ore deposits have been measured to estimate the temperature of formation of ore deposit. All of the sphalerite samples were enriched in ³⁴S compared with galena. Sulfur isotopic fractionation between sphalerite and galena ranges from 1.5 2.0 permil in the Taishu and Kamioka deposits, while in the Toyoha deposits ranges mostly from 2.5 to 3.0 permil. The fractionation of coexisting samples from early stage vein in Toyoha deposits is smaller than those from later stage vein. Using these isotopic fractionations and experimental temperature scale (Kiyosu, 1973), the temperature of formation is estimated to be 350° to 400°C in Kamioka deposits, 300° to 350°C in Taishu deposits and 200° to 250° in Toyoha deposits. These isotopic temperatures are slightly higher than filling temperatures determined from fluid inclusions of quartz and sphalerite.

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The vertical distributions of the ¹⁴C ¹³⁷CS ²¹⁰Pb, and ²¹⁴Pb concentrations, and of total organic carbon and nitrogen contents, were examined for the 50cm-long cored sediment collected from Lake Biwa(35. 3°N, 136°E, water depth: 70m). The sediment column was divided by 5mm intervals from surface to 10cm depth and by 10mm from 10 to 30cm depth. The ¹⁴C abundance, Δ¹⁴C, was measured by the direct detection of ¹⁴C atoms using a Tandetron accelerator mass spectrometer on acid-insoluble organic carbon extracted from 1.5g of each sediment sample divided vertically. Activities of ¹³⁷Cs, ²¹⁰Pb and ²¹⁴Pb were measured with a well-type pure-germanium detector, and the total organic carbon and nitrogen contents with a C-N corder, using about lg of each sample.
The followings were revealed through the present study:
(1) The sedimentation rate was calculated to be 0.0333±0.002g/cm²/yr(0.152±0.008cm/yr at the surface of the bottom sediment) by the ²¹⁰Pb method. The flux of 210Pb _excessdeposition at the surface of the bottom sediment was 0.45±0.04pCi/cm²/yr; this was about 60% of the annual ²¹⁰Pb deposition from the atmosphere.
(2) The ¹³⁷Cs concentration was widely distributed through the sediment column in comparison with a yearly change of the deposition rate from the atmosphere. The total amount of ¹³⁷Cs deposited in the sediment column was calculated as 2.63pCi/cm²; this was about 65% of the amount of total ¹³⁷Cs deposited so far in Osaka.
(3) Both organic carbon and nitrogen contents of the sediment decreased rapidly with increasing depths and reached constant values around 8-9cm in the depth. On the other hand, the carbon to nitrogen ratio was almost constant (C/N≈10) throughout the sediment column studied.
(4) The Δ¹⁴C value of the sediment increased from-250 to 40‰, with changing depths from 3cm to surface, owing to the addition of the artificially produced ¹⁴C to the atmosphere. The Δ¹⁴C value of the sediment before nuclear tests was about-250‰; this ¹⁴C concentration was 25% lower than that of the atmospheric CO₂ at that time. The increase in the ¹⁴C concentration of the sediment due to the bomb produced ¹⁴C was monotonous, lasting from 1956 to 1980. This change of Δ¹⁴C with time showed a quite different trend from the yearly change of Δ¹⁴C of the atmospheric CO₂, depending probably on the complicated mechanism of accumulating organic materials in the lake sediments.
(5) Radiocarbon dating on organic carbon of Lake Biwa sediments at depths from 3 to 4cm gave the ¹⁴C ages of 2200-2400y BP, which were quite older than the ²¹⁰Pb ages of A. D. 1945-55.

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日本海に面した地域では冬期に硫酸イオンの降下量が増加し,硫黄同位体比が高くなることから,大陸から大気汚染物質が越境してきているのではないかと考えられている.しかし,内陸にまで影響が及んでいるか否かは明らかではない.山形県米沢市は周囲を山地に囲まれた米沢盆地にあり,大規模な工場地帯が存在しない.米沢の湿性降下物に含まれる硫酸イオンの降下量は冬期に増加し,硫黄同位体比が高くなることから冬期の北西季節風によって海塩粒子が運び込まれている.しかし,非海塩性硫酸イオンの降下量は季節変動を示さず,非海塩性硫酸の硫黄同位体比も年間を通じてほぼ一定である.従って,米沢では年間を通じて外部からの大気汚染物質の移流は少なく,降雨に含まれる硫酸イオンは現地の人間活動に由来すると推定される.

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Radiocarbon ages have been measured for charred deposits on the surface of large-sized buried pottery jars (35-50cm in height, 30-40cm in diameter), which were collected during the 1986 excavation at the Morinoshita site, one of the archeological sites in Asahi-mura, Ohno-gun, Gifu Prefecture, using a Tandetron accelerator mass spectrometer at the Radioisotope Center, Nagoya University. According to archeological estimates, the buried jars were used in the Jomon period, first as vessels for boiling foods such as gathered nuts and vegetables and hunted animals, and then as containers for burying the bodies of stillborn babies and infants, as well as placentae of newborns, at the entrances of dwellings.
The ages measured for the 10-300mg of charred materials, most likely the food residues of ancient people, collected from the surface of each of seven pottery jars ranged from 3, 940 to 4, 450y.B.P. The average of the seven ages was 4, 180±90y.B.P. In addition, wood charcoal collected in an excavation of the residence site at Morinoshita, which had probably been used as part of the wood materials for constructing a house, was dated as 4, 140±140y.B.P. These dates suggest that the pottery jars were used, and the house built, in the late part of the Middle Jomon. This estimation is consistent with the results from typological studies of the jars: some of the jars have been identified as belonging to the Sori-III type (late Middle Jomon).
Stable-isotope ratios of carbon (¹³C/¹²C) have also been measured for four samples of the carbonaceous residues on the inner surface of the pottery jars to investigate the diet in the Jomon period, yielding δ¹³C_PDB values from -24.0 to -25.6‰. The δ¹³C_PDB values suggest that C3 plants, which use the Calvin-Benson photosynthetic pathway, and animals feeding on C3 plants can be the sources of the carbonaceous residues, but that the contributions to such residues from C4 plants (the Hatch-Slack photosynthetic pathway), animals feeding on C4 plants, and seafood may be negligible.

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All hot spring waters of non-volcanic origin are mostly distributed in the plutonic masses of the Cretaceous Bulkuksa granites and the Jurassic Daebo granites in the central and southeastern parts of the Korean peninsula. Temperature and pH of the hot spring waters range from 28.5° to 67℃ and from 6.55 to 9.40, respectively. Dongrae and Haiundae hot springs are located on or near the fault line, but others are not directly related to the fault structures. The ranges of δ¹⁸O and δD values for the hot spring waters are from -6.5 to -10.7‰ and -48.7 to -73.8‰, respectively, and for the local surface waters from -5.5 to -10.1‰ and -39.5 to -70.7‰, respectively. On the basis of stable isotopic and chemical compositions of the hot spring waters and geographical distribution of the hot springs in Korea, the hot spring waters can be divided into following three types; (1) Backam type characterized by low δ¹⁸O and δD values and alkaline waters. (2) Onyang type with weakly alkaline and intermediate isotopic values. Relatively high content of F^- and low Na⁺, Cl^-, and SO₄^2- contents. (3) Haiundae type, having high δ¹⁸O and δD values, weakly alkaline, and high concentration of Na⁺, K⁺, Ca²⁺, Cl^- and SO₄^2-. Most of the oxygen and hydrogen isotopic values are plotted slightly below the meteoric and surface water line defined by CRAIG (1961), and show a gradual decrease of the heavy isotope concentration from south to north, and west to east in the penin- sula possibly due to temperature and altitude effects. The hot spring waters are characterized by δ¹⁸O and δD values that are lower than those of the local surface waters at or near the hot springs, suggesting that the hot spring waters are derived from geographically further northern districts and topogra- phically higher mountain regions. The δ³⁴S values of dissolved sulfates range from +5.5 to +29.3‰, apparently reflecting the different sources of the sulfates for different hot springs. Sulfates of the hot spring waters from Haiundae and Pohang may be originated from sea water sulfate and those from Yusung, Duggu and Echon from the secondary sulfate produced by oxidation of sulfide minerals and the mixtures of the above two are thought to be responsible for Suanbo, Duksan, Dongrae, Magumsam and Chucksan hot springs.

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Oxygen and hydrogen isotope compositions (δ¹⁸O and δD) of natural waters can provide useful meteorological and hydrological information. In the present study, oxygen and hydrogen isotope compositions of snow samples from Mt. NAMUNANI (7,694m) and river water samples in Tibetan Plateau were analyzed to deduce sources of the water supplied to Tibetan Plateau. The following conclusions were obtained from isotopic result and d-excess parameter (d=δD-8•δ¹⁸O) which is useful as an index of the source of water vapor mass. 1) In Tibetan Plateau, oxygen and hydrogen isotope compositions of river waters depend on the altitude and on the extent of contribution to surface waters of different water vapor masses (whose sources are different such as Indian Ocean in the monsoon season, the Western areas such as the Mediterranean Sea in the premonsoon, and so on). 2) The d-excess parameters of river waters became larger and δ¹⁸O and δD values heavier with increasing latitude. This fact indicates that the contribution to surface waters of monsoon water vapor mass (smaller d value and lighter δ¹⁸O and δD values) from Indian Ocean becomes smaller with increasing latitude.

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A Japanese cypress (Kiso hinoki) grown in Gifu prefecture, Central Japan and a Shorea spruce in Sabah, Malaysia were analyzed for the ¹⁴C concentrations of annual tree rings (1945-1983). Each of annual rings (1958-1966) for the hinoki was divided radially into 3 or 4 consecutive sections. The ¹⁴C concentrations, Δ¹⁴C, of the sections were measured with a Tandetron accelerator mass spectrometer and compared with those of atmospheric CO₂. The good agreement was found between them; this suggested evidently that the Δ¹⁴C values of tree rings could be used to estimate the Δ¹⁴C values of atmospheric CO₂ in the past. Variations in Δ¹⁴C of annual tree rings (1945-1983 ) for the hinoki were found to be closely related with the history of executing the nuclear weapon tests in the atmosphere, by considering that the residence time was about 2 years for transferr-ing CO₂ from stratosphere to troposphere. By using the variation pattern of Δ¹⁴C common to most of trees, the average growth rate of the Shorea spruce (ca. 90cm in trunk diameter), having no growth ring, was estimated to be 5.5mm/yr. A latitude dependence of the Δ¹⁴C variations was found for annual rings (1963-1970) of trees grown in the northern troposphere (6°N-42°N). This phenomenon seemed to be closely related with the mechanism of global mixing for bomb-produced ¹⁴CO₂ in the atmosphere.

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A Tandetron accelerator mass spectrometer (AMS), based on mainly a tandem electrostatic accelerator and an apparatus to analyze charge state, energy, mass number, and atomic number of accelerated ions, has been used to measure ¹⁴C ages of geological and archeological samples, as well as ¹⁴C concentrations of natural samples, since 1983 at Nagoya University.
Traditional methods of radioactivity measurement have been applied to determine ¹⁴C ages of natural samples since 1947. However, their applications have been restricted to samples younger than 30000 to 40000y.B.P., as well as to ones from which 0.1 to 5 grams of carbon can be recovered. Usage of the Tandetron spectrometer has overcome these limitations. The amount of carbon necessary for the spectrometer is 0.2 to 5mg, being more than three orders of magnitude less than for traditional measurement. In addition, the oldest age measurable with the spectrometer has been extended to c.a. 60000y.B.P., as discussed in detail here.
The ¹⁴C background level of the spectrometer has been estimated by measuring ¹⁴C content of commercial graphite and mineral graphite from an ore deposit in Sri Lanka (Ceylon), which are too old to contain ¹⁴C. The background level corresponds to the apparent ¹⁴C age of 66340y.B.P. for commercial graphite and 64440y.B.P. for Ceylon graphite, as shown in Fig. 2. Amorphous carbon reduced by magnesium and graphite-like carbon deposited on iron-powder by hydrogen, from CO₂ prepared from “dead” carbon containing no ¹⁴C, show the apparent ¹⁴C ages of 37430 and 54000y.B.P., respectively. The solid carbon prepared from CO₂ gives a younger limit of the measurable oldest age than natural graphite, owing to the rather complicated preparation procedures which may introduce ¹⁴C contamination. Thus the method of producing amorphous carbon by reducing CO₂ with magnesium is not applicable to date such samples older than 40000y.B.P. The natural wood samples show ¹⁴C ages ranging from 59000 to 67860y.B.P., as shown in Fig. 3. These values are considered to indicate the oldest age measurable for woody materials.

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For the purpose of obtaining the most fundamental and important background data to identify the sources of natural waters with various occurences, isotopic compositions of oxygen and hydrogen were measured for meteoric and surface waters taken from Central and Northeast Japan, Okinawa Island, Mt. Fuji area and the Korean Peninsula. Monthly precipitation was also collected at Nagoya, Ontake, Takayama, Kanazawa, and Morioka (May〜December, 1982) and their isotopic compositions were measured. Altitude isotope effect is the most important factor determing the isotopic compositions of surface and meteoric waters in Central and Northeast Japan. In Central and Northeast Japan, average altitude effect for surface water was -0.25‰ per 100 m (δ¹⁸O) and -2.0‰ per 100m (δD). In Mt. Fuji area, that for both rain and snow was -0.4‰ per 100 m (δ¹⁸D) and -3.0‰ per 100 m (δD). At Happo-One that for snow was -0.3‰ per 100m (δ¹⁸O) and -2.5‰ per 100m (δD). The d-parameter (d = δD -8δ¹⁸O) of surface waters in Central and Northeast Japan tends to become higher continuously from the Pacific side to the Sea of Japan side, ranging from 9.1 to 22.4. In Okinawa Island, that was 7.3 on the average, ranging from 4.5 to 10.3. In Korea, that was 7.2 on the average, ranging from 4.3 to 10.1. The d-parameter suggests that the meteoric and surface waters in Central and Northeast Japan are dominated by differing contribution of moist air masses formed in two different environments, the Pacific Ocean and the Japan Sea.

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