The origin of Zn isotope fractionation in sulfides   总被引：2，自引：0，他引：2  

Toshiyuki Fujii  Frédéric Moynier  Francis Albarède 《Geochimica et cosmochimica acta》2011,75(23):7632-7643

Isotope fractionation of Zn between aqueous sulfide, chloride, and carbonate species (Zn²⁺, Zn(HS)₂, , , ZnS(HS)⁻, ZnCl⁺, ZnCl₂, , and ZnCO₃) was investigated using ab initio methods. Only little fractionation is found between the sulfide species, whereas carbonates are up to 1‰ heavier than the parent solution. At pH > 3 and under atmospheric-like CO₂ pressures, isotope fractionation of Zn sulfides precipitated from sulfidic solutions is affected by aqueous sulfide species and the δ⁶⁶Zn of sulfides reflect these in the parent solutions. Under high P_CO2 conditions, carbonate species become abundant. In high P_CO2 conditions of hydrothermal solutions, Zn precipitated as sulfides is isotopically nearly unfractionated with respect to a low-pH parent fluid. In contrast, negative δ⁶⁶Zn down to at least −0.6‰ can be expected in sulfides precipitated from solutions with pH > 9. Zinc isotopes in sulfides and rocks therefore represent a potential indicator of mid to high pH in ancient hydrothermal fluids.  相似文献   

Superoxide-mediated Fe(II) formation from organically complexed Fe(III) in coastal waters     

Manabu Fujii  Hiroaki Ito  T. David Waite 《Geochimica et cosmochimica acta》2008,72(24):6079-6089

Fe(III) complexed by organic ligands (Fe(III)L) is the primary form of dissolved Fe in marine and coastal environments. Superoxide, typically produced in biological and photochemical processes, is one of the reducing agents that contributes to transformation of Fe(III)L to bioavailable, free dissolved Fe(II) (Fe(II)′). In this work, the kinetics of superoxide-mediated Fe(II)′ formation from Fe(III)L in a simulated coastal water system were investigated and a comprehensive kinetic model was developed using citrate and fulvic acid as exemplar Fe-binding ligands. To simulate a coastal environment in laboratory experiments, Fe(III)L samples with various ligand/Fe ratios were incubated for 5 min to 1 week in seawater medium. At each ratio and incubation time, the rate of superoxide-mediated Fe(II)′ formation was determined in the presence of the strong Fe(II) binding ligand ferrozine by spectrophotometrically measuring the ferrous-ferrozine complex generated at a constant concentration of superoxide. The Fe(II)′ formation rate generally decreased with incubation time, as Fe(III)L gradually dissociated to form less reactive Fe(III) oxyhydroxide. However, when the ligand/Fe ratio was sufficiently high, the dissociation of Fe(III)L (and subsequent Fe precipitation) was suppressed and Fe(II)′ was formed at a higher rate. The rate of Fe(II)′ produced during the experiment was explained by the kinetic model. The model confirmed that both the ligand/Fe ratio and incubation time have a significant effect on the pathway via which Fe(II)′ is formed from Fe(III)-fulvic acid complexes.  相似文献   

First findings of decapod crustacea in the hadal zone     

A.J. Jamieson  T. Fujii  M. Solan  A.K. Matsumoto  P.M. Bagley  I.G. Priede 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(4):641-647

Since the first major hadal sampling efforts in the 1950s, crustaceans of the order Decapoda have been thought absent from the hadal zone (6000–11,000 m) with no representatives documented >5700 m. A baited video lander deployed at 6007, 6890 and 7966 m in the Kermadec Trench, 8798 and 9729 m in the Tonga Trench (SW Pacific), 6945 and 7703 m in the Japan Trench and 5469 m in the Marianas region (NW Pacific) has now revealed a conspicuous presence of the Benthesicymid prawn Benthesicymus crenatus Bate 1881. Decapods were observed at all sites except at 7966 m in the Kermadec Trench and the two Tonga Trench sites, making the deepest finding 7703 m in the Japan Trench, 2000 m deeper than previously thought. These natantian decapods were readily attracted to fish bait and, rather than feeding on the bait itself, were observed preying upon smaller scavenging amphipods. These are the first observations of predation in the hadal zone. In less than 10 h of bottom time, 12 observations of 10 individuals were documented at 6007 m and 5 observations of 3 individuals were documented at 6890 m in the Kermadec Trench. In the Japan Trench at 6945 m 29 observations of 20 individuals were documented whilst only one individual was seen at 7703 m. Two individuals were observed in the abyssal Marianas Region (5575 m). Also, in the Kermadec Trench, individual caridean prawns (Acanthephyra spp.) were observed at 6007 and 6890 m, proving categorically that the crustacean order of Decapoda is represented in the hadal zone.  相似文献   

Consistency and fidelity of Indonesian-throughflow total volume transport estimated by 14 ocean data assimilation products     

Tong Lee  Toshiyuki Awaji  Magdalena Balmaseda  Nicolas Ferry  Yosuke Fujii  Ichiro Fukumori  Benjamin Giese  Patrick Heimbach  Armin Köhl  Simona Masina  Elisabeth Remy  Anthony Rosati  Michael Schodlok  Detlef Stammer  Anthony Weaver 《Dynamics of Atmospheres and Oceans》2010

Monthly averaged total volume transport of the Indonesian throughflow (ITF) estimated by 14 global ocean data assimilation (ODA) products that are decade to multi-decade long are compared among themselves and with observations from the INSTANT Program (2004–2006). The main goals of the comparisons are to examine the consistency and evaluate the skill of different ODA products in simulating ITF transport. The ensemble averaged, time-mean value of ODA estimates is 13.6 Sv (1 Sv = 10⁶ m³/s) for the common 1993–2001 period and 13.9 Sv for the 2004–2006 INSTANT Program period. These values are close to the 15-Sv estimate derived from INSTANT observations. All but one ODA time-mean estimate fall within the range of uncertainty of the INSTANT estimate. In terms of temporal variability, the scatter among different ODA estimates averaged over time is 1.7 Sv, which is substantially smaller than the magnitude of the temporal variability simulated by the ODA systems. Therefore, the overall “signal-to-noise” ratio for the ensemble estimates is larger than one. The best consistency among the products occurs on seasonal-to-interannual time scales, with generally stronger (weaker) ITF during boreal summer (winter) and during La Nina (El Nino) events. The scatter among different products for seasonal-to-interannual time scales is approximately 1 Sv. Despite the good consistency, systematic difference is found between most ODA products and the INSTANT observations. All but the highest-resolution (18 km) ODA product show a dominant annual cycle while the INSTANT estimate and the 18-km product exhibit a strong semi-annual signal. The coarse resolution is an important factor that limits the level of agreement between ODA and INSTANT estimates. Decadal signals with periods of 10–15 years are seen. The most conspicuous and consistent decadal change is a relatively sharp increase in ITF transport during 1993–2000 associated with the strengthening tropical Pacific trade wind. Most products do not show a weakening ITF after the mid-1970s’ associated with the weakened Pacific trade wind. The scatter of ODA estimates is smaller after than before 1980, reflecting the impact of the enhanced observations after the 1980s. To assess the representativeness of using the average over a three-year period (e.g., the span of the INSTANT Program) to describe longer-term mean, we investigate the temporal variations of the three-year low-pass ODA estimates. The average variation is about 3.6 Sv, which is largely due to the increase of ITF transport from 1993 to 2000. However, the three-year average during the 2004–2006 INSTANT Program period is within 0.5 Sv of the long-term mean for the past few decades.  相似文献   

Case 24 reevaluation of anomalous vertical crustal movement associated with the 1964 Niigata, Japan, earthquake     

Y. Fujii  K. Nakane 《Pure and Applied Geophysics》1997,149(1):115-127

It is widely acknowledged that the 1964 Niigata, Japan, earthquake is associated with the preseismic anomalous crustal movement detected by repetition of precise levelings, while some doubts have been raised on the validity of reported precursory movement. Validity of the crustal movement is tested by an analysis of tidal data. When we are able to deduce crustal movement referring to the determined mean sea level, we can discuss the absolute crustal movement. Tidal data along the Japan Sea coast of northeast Japan are analyzed by the method developed inTsumura (1963, 1970) for the period from 1955 to 1986.The final results at tidal station, Nezugaseki, indicate clearly the steady-state movement during 1955–1958, 4 cm of abnormal upheaval from 1959–1964, 20 cm of coseismic abrupt subsidence, and 4 cm of postseismic rapid subsidence, and finally very gradual subsidence. Thus the present results support the idea of the typical pattern of the seismic crustal movement, including the precursory movement.  相似文献   

Design of mooring system of oil storage barges in shallow water     

Hitoshi Fujii  Kunihiro Ikegami  Masanori Shuku 《Applied Ocean Research》1982,4(1):41-50

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Contemporary crustal deformations in the Izu peninsula,Honshu, Japan and acceleration of plate bending in the northernmost part of the Philippine Sea plate     

Yoichiro Fujii 《Pure and Applied Geophysics》1991,136(2-3):315-341

Since the beginning of the anomalous vertical crustal movement in the Izu peninsul, Honshu, Japan, many repeated precise levellings have been carried out by the Geographical Survey Institute. Trilaterations covering the entire Izu peninsula have also been carried out by the Geographical Survey Institute. A new technique is developed to adjust the results of levellings, because they had been carried out for different epochs along each levelling route and because of rapid vertical crustal movements. In conventional least-squares adjustment of levelling network, only corrections to the approximate height are assumed to be unknown, while in the present analysis a special model in which rates of vertical deformation at any bench marks are also assumed to be unknown, is adopted. In addition, tidal stations along the coast of the Izu peninsula yield the rate of vertical crustal movement from analysis of tidal data independent of levelling data. We select several special bench marks in which rates of vertical movement are determined by tidal analysis, thereafter special adjustment is applied according to the type of network.The results show that the peninsula is inclined to the south-west. Uplift in the northeastern part of the peninsula is accompanied by remarkable subsidence in the southwest. The rate of contemporary inclination is many times higher than the rate during the period from 1929 to 1972.The deformation is concentrated in the area whereNakamura (1979, 1980) pointed out the bending of the Philippine Sea plate. The mode and rate of the detected crustal deformation suggest the accelerated bending of the peninsula. There are some local uplift that deviate from the general pattern of deformation. The most remarkable land uplift was observed near Ito, a city within the peninsula, and the focus of this uplift migrated with time. The accelerated plate bending will produce an extension at the earth's surface and contraction in the deeper part of the subcrustal layer, additionally it triggered the intrusion of magma from the deeper part to the shallower. Moreover, the accelerated plate bending also triggered seismic swarms and destructive, earthquakes in and around the peninsula.  相似文献   

Inventory of perennial snow patches in Central Japan     

Prof. Dr. K. Higuchi  T. Iozawa  Dr. Y. Fujii  H. Kodama 《GeoJournal》1980,4(4):303-311

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Rayleigh wave scattering at wedge corners with major wedge angles     

Masayoshi Nakano  Kazunari Fujii  Shozaburo Takeuchi 《Pure and Applied Geophysics》1988,128(1-2):119-132

Theoretical calculations were performed on reflected and transmitted Rayleigh waves and scattered body waves, in the case where a two-dimensional Rayleigh wave is incident to a wedge-shaped medium having a wedge angle between 250° and 290° and arbitrary value of Poisson ratio. The reflection and transmission coefficients of Rayleigh waves were also experimentally measured in cases of wedges with 190° to 330° wedge angles. The method of theoretical analysis and the techniques of experiment are based on those developed in our preceding research (W-1. W-2 and W-3). Compared with the results where the wedge angle is smaller than 180° (W-1 and W-2), all features show consistent variation with wedge angle.  相似文献   

青藏高原那曲地区冰冰雹天气系统中的大气电场   总被引：12，自引：9，他引：3  

周筠 Kajik.  M 《高原气象》2000,19(3):339-347

利用１９９８年４～９月间进行的ＧＡＭＥ－ＴＩＢＥＴ青堪稿原云和降水的多普勒雷达及大气平均电场加强期观测实验资料,对青藏高原那曲地区的冰雹天气系统中的大民电场作了定量观测和研究。结果表明：在降雹过程中大气电场强度基本上系统中的大气电场强度基本上均为负值,其峰值也均强于－２２ｋＶｍ＾－１;在降雹过程中随着降雹时间的临近,大民场强度基本不断增强,但降雹开始时大气电场强度并不达到其峰值,峰值出现的时刻比开  相似文献