Variation of rare earth concentrations in pigeonitic and hypersthenic rock series from Izu-Hakone region,Japan     

Toshihiko Yajima  Hideo Higuchi  Hiroshi Nagasawa 《Contributions to Mineralogy and Petrology》1972,35(3):235-244

The abundances of rare earth elements in 5 each of aphyric volcanic rocks of pigeonitic and hypersthenic rock series from Izu-Hakone region have been determined by neutron activation analysis. Pigeonitic rock series show rare earth patterns with relative depletion of lighter rare earths (low lanthanum type) and large increase in rare earth abundances with differentiation. Hypersthenic rock series show higher lanthanum abundances (high lanthanum type) compared with pigeonitic rock series. The differences in rare earth patterns between two rock series are compatible with the theory of independent magmatic generation of these two series. Variation of rare earth patterns in both series have been examined by a model of magmatic differentiation based on the observed rare earth partition coefficients.  相似文献   

Climato-limnological signals during the past 260 000 years in physical properties of bottom sediments from Lake Baikal     

Kenji Kashiwaya  Masayuki Ryugo  Masae Horii  Hideo Sakai  Toshio Nakamura  Takayoshi Kawai 《Journal of Paleolimnology》1999,21(2):143-150

The St.16 core obtained from the Academician Ridge of Lake Baikal in eastern Siberia may span about 260 000 years, and some physical properties of the core samples are closely related to aquatic paleoproductivity and climatic change. The median of grain size, grain density, and water content fluctuate synchronously. They also are connected with change in the abundance of biogenic silica (diatoms). The physical parameters indicate that there were high aquatic productivity periods around interglacial periods (MIS 5 and 7; 70 000-125 000 yr B.P. and 180 000-250 000 yr B.P.). Comparatively large clastics were transported from outside of the lake through various routes (ice rafting, etc.) in addition to fluvial routes during the glacials or 'stadials. There are ca. 20 000 yr, 40 000 yr and 100 000 yr periods in the variations of physical properties. These are related to the three Milankovitch parameters of solar insolation.  相似文献   

Review of the geomagnetic secular variations on the historical time scale     

Takesi Yukutake 《Physics of the Earth and Planetary Interiors》1979,20(2-4):83-95

In view of the classification of the geomagnetic field into its axisymmetric and non-axisymmetric parts, studies of geomagnetic secular variations on the historical time-scale are reviewed. The westward drift of the geomagnetic field, which is one of the most conspicuous features of its secular variation, is examined first. The non-axisymmetric field during the past several hundred years can be well approximated by the superposition of two constant-magnitude fields, a standing and a drifting field, whose lifetimes are supposed to be longer than 1000 years. It is pointed out that the sectorial term of the non-dipole standing field is small compared with the drifting one. The lack of the n = M = 2 term of the standing field is particularly remarkable.

On the other hand, the equatorial dipole field is likely to consist of two components which are both drifting. One drifts westwards with a normal velocity and the other eastwards with a small velocity.

Besides the pronounced westward drift in an east-west direction, the poleward movements of particular foci of the secular variation are noted. This may, however, be related to the rapid growth of the axisymmetric quadrupole field.

The time variation of the dipole field is briefly examined. As far as the data on the historical time scale are concerned, an antiparallel relationship seems to exist between the variations in the dipole and the quadrupole field. As the dipole moment decreases, the magnitude of the quadrupole moment increases. Finally, characteristic oscillation periods of the dipole field are examined. Although the data are few, a 60–70-year period, a 400–600-year and a 8000-year period emerge as the dominant periods.  相似文献   

Chemical fractionations in meteorites—X. Ureilites     

Hideo Higuchi  John W Morgan  R Ganapathy  Edward Anders 《Geochimica et cosmochimica acta》1976,40(12):1563-1571

Four ureilites (Dyalpur, Goalpara, Haverö, and Novo Urei) were analyzed by radiochemical neutron activation analysis for Ag, Au, Bi, Br, Cd, Cs, Ge, In, Ir, Ni, Rb, Re, Sb, Se, Te, Tl, and U. An attempt has been made to resolve the data into contributions from the parent ultramafic rock and the injected, carbon- and gas-rich vein material. Interelement correlations, supported by analyses of separated vein material (WANKE et al, 1972), suggest that the vein material is enriched about 10-fold in refractory Ir and Re over moderately volatile Ni and Au, and is low in volatiles except Ge, C, and noble gases. It appears to be a refractory-rich nebular condensate that precipitated carbon by surface catalytic reactions at ˜500K and trapped noble gases but few other volatiles. The closest known analogue is a Cr- and C-rich fraction from the Allende meteorite, highly enriched in heavy noble gases and noble metals. By analogy with Allende, the gas-bearing phase in ureilites may have been an Fe, Cr-sulfide.

The ultramafic rock contains siderophiles and chalcophiles (Ni, Au, Ge, S, Se) at ˜0.05 of Cl chondrite level, and highly volatile elements (Rb, Cs, Bi, Tl, Br, Te, In, Cd) at ˜0.01 Cl level. It probably represents the residue from partial melting of a C3V-like chondrite body, under conditions where phase separation was incomplete so that some liquid was retained. The vein material was injected into this rock at some later time.  相似文献   

Chemical fractionations in meteorites—IX. C3 chondrites     

Edward Anders  Hideo Higuchi  R. Ganapathy  John W. Morgan 《Geochimica et cosmochimica acta》1976,40(9):1131-1139

Four C3V chondrites (Grosnaja, Kaba, Mokoia, Vigarano) and three C3O chondrites (Felix, Kainsaz, and Lancé) were analyzed by radiochemical neutron activation for 17 trace elements. Both classes show a typical chondritic step pattern, reflecting loss of volatiles during chondrule formation. Elements condensing above 1300 K (U, Re, Ir, Ni) are present in essentially Cl chondrite proportions, while moderately volatile elements condensing between 1300 K and 800 K (Ge, Rb, Ag) are depleted by a factor of 0.44. However, elements condensing below 700 K (S, Cs, Bi, Tl, Br, Se, Te, In, Cd) are depleted to a still greater degree, and more so in the Ornans subclass (factor of 0.24, except Cd 0.007) than in the Vigarano subclass (factor of 0.29). This additional depletion may be due to a slight (less than 3-fold) dust-gas fractionation, by settling of dust to the median plane of the solar nebula. Among other chondrite classes, ordinary chondrites show a similar depletion, but C2 chondrites do not. Possibly the undepleted meteorites formed in one of the convection zones of the nebula predicted by Cameron and Pine, whereas the depleted meteorites formed in a quiescent region.The condensation of chalocophile elements as a function of H₂S partial pressure is discussed, in an attempt to explain the drastic difference in Cd abundance between the two subclasses. It appears that the $\text{H}{}_2\text{S}\text{H}{}_2$ ratio is the key variable. C3O's seem to have condensed in a region where enough metallic Fe was present to buffer the H₂S pressure, while C3V's condensed in a more oxidized region, where H₂S was in excess. Accretion temperatures, for an assumed nebular pressure of 10^?5 atm, were between 415 and 430 K for C3O's and less than 440 K for C3V's.Two slightly volatile elements, Sb and Au, show variable depletion, presumably reflecting variable loss during chondrule formation. Indeed, their depletion correlates with the abundance of iron-poor olivine, a measure of the peak temperature and time during chondrule formation.  相似文献   

Detection of white spot syndrome virus (WSSV) ofPenaeus chinensis by in situ hybridization     

Zhan Wen-bin  Wang Yuan-hong  Zhang Zhi-dong  Fukuda Hideo 《中国海洋湖沼学报》2000,18(3):241-246

White Spot Syndrome Virus (WSSV) was purified from hemolymph of infected shrimp. After nucleic acid extraction from the purified virus particles, EcoR I-digested fragments of the WSSV genome were cloned; three of these fragments were used as non-radioactive probes labeled with DIG-11-dUTP. The probes hybridized in situ, with sections located in the nuclei of all WSSV-infected tissues. The virus was detected in the gill, stomach, epidermis, and connective tissue and so on, but not detected in healthy shrimp tissues and epithelial cells of hepatopancreatic tubules of diseased shrimp. This work was supported by SRF for ROCS, SEM and the National 863 Project (Grant 819-Q-08) and Project under major State Basic Research Development Program (Grant G1999012002).  相似文献   

Perturbed physics ensemble using the MIROC5 coupled atmosphere–ocean GCM without flux corrections: experimental design and results     

Hideo Shiogama  Masahiro Watanabe  Masakazu Yoshimori  Tokuta Yokohata  Tomoo Ogura  James D. Annan  Julia C. Hargreaves  Manabu Abe  Youichi Kamae  Ryouta O’ishi  Rei Nobui  Seita Emori  Toru Nozawa  Ayako Abe-Ouchi  Masahide Kimoto 《Climate Dynamics》2012,39(12):3041-3056

In this study, we constructed a perturbed physics ensemble (PPE) for the MIROC5 coupled atmosphere–ocean general circulation model (CGCM) to investigate the parametric uncertainty of climate sensitivity (CS). Previous studies of PPEs have mainly used the atmosphere-slab ocean models. A few PPE studies using a CGCM applied flux corrections, because perturbations in parameters can lead to large radiation imbalances at the top of the atmosphere and climate drifts. We developed a method to prevent climate drifts in PPE experiments using the MIROC5 CGCM without flux corrections. We simultaneously swept 10 parameters in atmosphere and surface schemes. The range of CS (estimated from our 35 ensemble members) was not wide (2.2–3.2?°C). The shortwave cloud feedback related to changes in middle-level cloud albedo dominated the variations in the total feedback. We found three performance metrics for the present climate simulations of middle-level cloud albedo, precipitation, and ENSO amplitude that systematically relate to the variations in shortwave cloud feedback in this PPE.  相似文献   

Short term variability of Particle fluxes and its relation to variability in sea surface temperature and chlorophylla field detected by Ocean Color and Temperature Scanner (OCTS) off Sanriku, northwestern North Pacific in the spring of 1997     

Toshiro Saino  Shaoling Shang  Yoshihisa Mino  Koji Suzuki  Hideaki Nomura  Sei-ichi Saitoh  Hideo Miyake  Toshiyuki Masuzawa  Koh Harada 《Journal of Oceanography》1998,54(5):583-592

A sediment trap experiment was carried out in conjunction with an over flight of Ocean Color Temperature Scanner (OCTS) on board Advanced Earth Observing Satellite (ADEOS) at 40°N, 143°E off Sanriku in April to May 1997. Short term variability of particle fluxes was examined at depths of 450 m and 600 m from April 6 to May 1 with a sampling interval of two days, and at 450 m with one day interval from 2nd to 10th May. Daily averaged mass flux at 450 m and 600 m was 815 mg m⁻²d⁻¹ and 862 mg m⁻²d⁻¹, respectively. A sharp increase in mass flux was observed during the period from April 26 to April 29 with the highest mass flux of 8 g m⁻²d⁻¹. About 85% of the total mass flux for the entire duration (26 days) was collected within these 4 days. Trapped material during the peak flux period was mainly composed of diatoms dominated byThalassiosira spp. and resting spores ofChaetoceros spp. This suggested that the peak flux was the result of (a) diatom bloom(s) in the euphotic column. Current meter records at 420 m showed that on April 26 and 27, the period when the peak flux was observed, the southwestward current had diminished in strength and changed its direction northwestward. Low current speeds appeared to have enhanced trap efficiency to help form the peak flux. A time series of OCTS Intensive-LAC (Local Area Coverage: Region B) images from mid-March to early May was examined todetect phytoplankton bloom(s). In the March 26th Chl image, high concentration region was restricted to the southwest off Cape Erimo, but spread around the warm core ring (WCR) 93A by April 10. East of the WCR93A, high Chl concentration remained steady until May, but to the west of the WCR93A, Chl decreased rapidly before the 19th of April. From this observation we suspect that the peak flux observed at the end of April originated from a bloom, which ceased on the 17th or 18th of April, in the region north of 40°N and west of 143°E. Taking the current meter records into account, the source region for the trapped material is most likely around southwest of the Cape Erimo.  相似文献   

Short-term variabilities of upper ocean current in the warm pool region during TOGA/COARE IOP     

Iwao Ueki  Kunio Kutsuwada  Hideo Inaba  Arata Kaneko 《Journal of Oceanography》1998,54(3):227-240

Oceanic current data in the warm pool region of the western equatorial Pacific measured by upward-looking moored Acoustic Doppler Current Profilers at two equatorial sites (147°E and 154°E) and two off-equatorial sites (2°N and 2°S, 156°E) during TOGA/COARE Intensive Observing Period (IOP) from November 1992 to February 1993 are used to examine short-term variabilities in the upper layer above 160–240 m. In time series of the zonal and meridional currents in many layers, spectral peaks are found at periods around 2 days and 4 days in addition to high energies in a period range longer than 10 days. The signal with the period of about 2 days has significantly high energies at all sites, and its magnitude is higher for the meridional current than for the zonal one. This signal is especially active in the first half of IOP from November to December in 1992. In this period, the quasi-2-day signal in the current field is coherent between northern (2°N) and southern (2°S) stations, but it has no evident relationship with that in the surface wind field around the stations. The quasi-4-day signal with the period of about 4 days has highest energies in layers above 160 m at the southern station, and is coherent between northern and southern stations. Besides, the signal at the station of 2°S has a significantly high coherence with that in the wind at the southern station, suggesting that it is a local phenomenon.  相似文献   

Seismological asperities from the point of view of dynamic rupture modeling: the 2007 Mw6.6 Chuetsu-Oki,Japan, earthquake     

Hideo Aochi  Masayuki Yoshimi 《Journal of Seismology》2016,20(4):1089-1105

We study the ground motion simulations based on three finite-source models for the 2007 Mw6.6 Niigata Chuetsu-oki, Japan, earthquake in order to discuss the performance of the input ground motion estimations for the near-field seismic hazard analysis. The three models include a kinematic source inverted from the regional accelerations, a dynamic source on a planar fault with three asperities inferred from the very-near-field ground motion particle motions, and another dynamic source model with conjugate fault segments. The ground motions are calculated for an available 3D geological model using a finite-difference method. For the comparison, we apply a goodness-of-fit score to the ground motion parameters at different stations, including the nearest one that is almost directly above the ruptured fault segments. The dynamic rupture models show good performance. We find that seismologically inferred earthquake asperities on a single fault plane can be expressed with two conjugate segments. The rupture transfer from one segment to another can generate a significant radiation; this could be interpreted as an asperity projected onto a single fault plane. This example illustrates the importance of the fault geometry that has to be taken into account when estimating the very-near-field ground motion.  相似文献