Accurate Determination of Chlorine,Bromine and Iodine in U.S. Geological Survey Geochemical Reference Materials by Radiochemical Neutron Activation Analysis          下载免费PDF全文

Shun Sekimoto  Mitsuru Ebihara 《Geostandards and Geoanalytical Research》2017,41(2):213-219

Trace amounts of three halogens (chlorine, bromine and iodine) in seventeen U.S. Geological Survey (USGS) geochemical reference materials were determined by radiochemical neutron activation analysis (RNAA). The materials analysed were AGV‐2 (andesite), BCR‐2, BHVO‐2 and BIR‐1a (basalts), CLB‐1 (coal), COQ‐1 (carbonatite), DGPM‐1 (disseminated gold ore), DNC‐1a (dolerite), DTS‐2b (dunite), GSP‐2 (granodiorite), Nod‐A‐1 and Nod‐P‐1 (manganese nodules), QLO‐1a (quartz latite), SBC‐1 (marine shale), SDC‐1 (mica schist), SGR‐1b (shale rock) and W‐2a (diabase). The chlorine, bromine and iodine contents were determined to be 5.64 mg kg^?1 (BIR‐1a) to 4410 mg kg^?1 (Nod‐A‐1), 0.039 mg kg^?1 (BIR‐1a) to 52.1 mg kg^?1 (CLB‐1), and 0.041 mg kg^?1 (BIR‐1a) to 599 mg kg^?1 (CLB‐1), respectively. The RNAA data of the three halogens were compared with the corresponding data in the literature.  相似文献   

Detailed abundances of rare earth elements,thorium and uranium in chondritic meteorites: An ICP-MS study     

Kazunori Shinotsuka  Hiroshi Hidaka  Mitsuru Ebihara 《Meteoritics & planetary science》1995,30(6):694-699

Abstract— Inductively coupled plasma mass spectrometry (ICP-MS) was successfully applied to bulk samples of Allende, Jilin, Modoc, Saint-Séverin and Atlanta for the determination of rare earth elements (REE) (Y and 14 lanthanoids), Th and U. The results of ICP-MS showed good agreement with recommended values, and their reproducibilities were high enough to discuss the detailed abundances of lanthanoids and actinoids in chondritic meteorites. For the Allende reference sample issued by the Smithsonian Institution, a positive anomaly of Tm, a fractionation between light REE and heavy REE and a high Th/U ratio were observed in the CI-normalized abundances of REE, Th and U. These features are common for group II inclusions in Allende, suggesting that the abundances of refractory lithophiles in Allende are somewhat influenced by those in a specific constituent. For the other chondritic meteorites, a zigzag alteration was commonly observed in the heavy-REE region of their CI-normalized abundance patterns. It is suggested that such a zigzag pattern is attributable to erratically high abundances of monoisotopic REE (Tb, Ho and Tm) in the CI values. Abundances of REE, Th and U in the bulk samples are also discussed separately in detail.  相似文献   

Solar-system abundances of the elements     

Edward Anders  Mitsuru Ebihara 《Geochimica et cosmochimica acta》1982,46(11):2363-2380

A new abundance table has been compiled, based on a critical review of all C1 chondrite analyses up to mid-1982. Where C1 data were inaccurate or lacking, data for other meteorite classes were used, but with allowance for fractionation among classes. In a number of cases, interelement ratios from meteorites or lunar and terrestrial rocks as well as solar wind were used to check and constrain abundances. A few elements were interpolated (Ar, Kr, Xe, Hg) or estimated from astronomical data (H, C, N, O, He, Ne).For most elements, the new abundances differ by less than 20% from those of Cameron (1982a). In 14 cases, the change is between 20 and 50% (He, Ne, Be, Br, Nb, Te, I, Xe, La, Gd, Tb, Yb, Ta and Pb) and in 5 others, it exceeds 50% (B, P, Mo, W, Hg). Some important interelement ratios ($\text{Na}\text{K}$, $\text{Se}\text{Te}$, $\text{Rb}\text{Sr}$, $\text{Kr}\text{Xe}$, $\text{La}\text{W}$, $\text{Th}\text{U}$, $\text{Pb}\text{U}$, etc.) are significantly affected by these changes.Three tests were carried out, to see how closely C1 chondrites approximate primordial solar system abundances. (1) A plot of solar vs Cl abundances shows only 7 discrepancies by more than twice the nominal error of the solar abundance: Ga, Ge, Nb, Ag, Lu, W and Os. Most or all apparently reflect errors in the solar data or f-values. (2) The major cosmochemical groups (refractories, siderophiles, volatiles, etc.) show no significant fractionation between the Sun and C1's, except possibly for a slight enrichment of volatiles in Cl's. (3) Abundances of odd-A nuclides between A = 65 and 209 show an almost perfectly smooth trend, with elemental abundances conforming to the slope defined by isotopic abundances. There is no evidence for systematic fractionation of the major cosmochemical groups from each other. Small irregularities (10–15%) show up in the Ag-Cd-In and Sm-Eu regions; the former may be due to a ~ 15% error in the Ag abundance and the latter, to a 10–20% fractionation of Eu during condensation, to contamination of C1 chondrites with interplanetary dust during regolith exposure, or to a change from s-process to r-process dominance.It appears that the new set of abundances is accurate to at least 10%, as irregularities of 5–10% are readily detectable. Accordingly, Cl chondrites seem to match primordial solar-system matter to ? 10%, with only four exceptions. Br and I are definitely and B is possibly fractionated by hydrothermal alteration, whereas Eu seems to be enriched by nebular condensation or regolith contamination.  相似文献   

A kinematical consideration on behavior of a front within a typhoon area     

Prof. Mitsuru Sekioka 《Meteorology and Atmospheric Physics》1972,21(1):1-12

Summary Considering that a front is a substantial line, the behavior of a pre-existing front is investigated kinematically within a typhoon area in middle latitudes. The wind field of a typhoon is represented by the Rankine combined vortex to determine the deformation and displacement of the pre-existing front from trajectories of each point constituting the front by Petterssen's method of successive approximations. Comparison of the results thus obtained for the cases of typhoons Doris and Winnie, 1966, with those by the surface analysis shows good agreement.

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Eine kinematische Betrachtung über das Verhalten einer Front in einem Taifunbereich

Zusammenfassung Unter der Annahme, daß eine Front eine substantielle Linie ist, wird das Verhalten einer bereits vorhandenen Front, die in einen Taifun-Bereich in mittleren Breiten einbezogen wird, kinematisch untersucht. Das Windfeld eines Taifuns wird durch einen zusammengesetzten Rankine-Wirbel dargestellt, um die Deformation und Verlagerung der bereits vorhandenen Front aus den Trajektorien jedes Punktes der Front nach der Petterssen-Methode der sukzessiven Approximation zu berechnen. Ein Vergleich der Resultate, die auf diese Weise für die Taifune Doris und Winnie (1966) erhalten wurden, mit Ergebnissen von Bodenkarten-Analysen zeigt gute Übereinstimmung.

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With 7 Figures  相似文献   

Distribution of cyanobacteria and other picophytoplankton in the western North Pacific Ocean,Summer 1989     

Tsuneo Odate  Mitsuru Yanada  Lourdes V. Castillo  Yoshiaki Maita 《Journal of Oceanography》1990,46(4):184-189

Cell densities of phycoerythrin-fluorescing cyanobacteria and other chlorophyll-fluorescing picophytoplankton in the 0.2–2.0 µm size fraction were investigated, using an epifluorescence microscope, in the western North Pacific Ocean (36.5–44.0 °N, 155.0°E) in the summer of 1989. Cyanobacteria were most abundant in the surface of the subtropical water (36.5–38.0°N) and less in the northern sea area (39.5–44.0°N). The cell density of other picophytoplankton was, however, high in the northern part and low in the subtropical water. Results showed that algae other than cyanobacteria may significantly contribute to the picophytoplankton community under the low water temperature conditions of open waters. Chlorophylla concentration represented well the abundance of picophytoplankton other than cyanobacteria, but had no significant correlation with the cyanobacteria cell density. Chlorophylla-based data must be interpreted with caution, since the abundances of cyanobacteria were often considerably different even though the chlorophylla concentrations were the same level.  相似文献   

U–Pb zircon ages of the Nakanogawa Group in the Hidaka Belt,northern Japan: Implications for its provenance and the protolith of the Hidaka metamorphic rocks          下载免费PDF全文

Futoshi Nanayama  Yutaka Takahashi  Toru Yamasaki  Mitsuru Nakagawa  Hideki Iwano  Tohru Danhara  Takafumi Hirata 《Island Arc》2018,27(2)

Zircon U–Pb ages of two acidic tuff and two turbidite sandstone samples from the Nakanogawa Group, Hidaka Belt, were measured to estimate its depositional age and the development of the Hokkaido Central Belt, northeast Japan. In the northern unit, homogeneous zircons from pelagic acidic tuff from a basal horizon dated to 58–57 Ma, zircons from sandstone from the upper part of the unit dated to 56–54 Ma, and zircons from acidic tuff from the uppermost part dated to 60–56 Ma and 69–63 Ma. Both of the tuff U–Pb ages are significantly older than the youngest radiolarian fossil age (66–48 Ma). Therefore, the maximum depositional age of the turbidite facies in the northern unit is 58 Ma and the younger age limit, estimated from the fossil age, is 48 Ma. In the southern unit, homogeneous zircons from turbidite sandstone dated to 58–57 Ma. Thus the depositional age of this turbidite facies was interpreted to be 66–56 Ma from the fossil age, probably close to 57 Ma. Most of the zircon U–Pb ages from the Nakanogawa Group are younger than 80 Ma, with a major peak at 60 Ma. This result implies that around Hokkaido volcanic activity occurred mainly after 80 Ma. Older zircon ages (120–80 Ma, 180–140 Ma, 340–220 Ma, 1.9 Ga, 2.2 Ga, and 2.7 Ga) give information about the provenance of other rocks in the Hidaka Belt. It is inferred that the Nakanogawa Group comprises protoliths of the upper sequence of the Hidaka Metamorphic Zone, which therefore has the same depositional age as the Nakanogawa Group (66–48 Ma). The depositional ages of the lower sequence of the Hidaka Metamorphic Zone and the Nakanogawa Group are probably the same.  相似文献   

Drop size distribution and kinetic energy load of rainfall events in the highlands of the Central Rift Valley,Ethiopia     

Derege Tsegaye Meshesha  Atsushi Tsunekawa  Mitsuru Tsubo  Nigussie Haregeweyn  Enyew Adgo 《水文科学杂志》2013,58(12):2203-2215

Abstract

Knowledge of rainfall characteristics is important for estimating soil erosion in arid areas. We determined basic rainfall characteristics (raindrop size distribution, intensity and kinetic energy), evaluated the erosivity of rainfall events, and established a relationship between rainfall intensity I and volume-specific kinetic energy KE_vol for the Central Rift Valley area of the Ethiopian highlands. We collected raindrops on dyed filter paper and calculated KE_vol and erosivity values for each rainfall event. For most rainfall intensities the median volume drop diameter (D₅₀) was higher than expected, or reported in most studies. Rainfall intensity in the region was not high, with 8% of rain events exceeding 30 mm h^-1. We calculated soil erosion from storm energy and maximum 30-min intensity for soils of different erodibility under conditions of fallow (unprotected soil), steep slope (about 9%) and no cover and management practice on the surface, and determined that 3 MJ mm ha^-1 h^-1 is the threshold erosivity, while erosivity of >7 MJ mm ha^-1 h^-1 could cause substantial erosion in all soil types in the area.