Monte Carlo study on distortion of the space-dimension in COBE monopole data     

Minoru Biyajima  Takuya Mizoguchi 《Astrophysics and Space Science》2014,350(1):317-323

A concise explanation of studies on distortion of space-time dimension is briefly introduced. Second we obtain the limits (i.e., bounded values) of the dimensionless chemical potential μ, the Sunyaev–Zeldovich (SZ) effect y and distortion of the space-dimension ε by Monte Carlo (MC) analysis of the parameter set (T, d=3+ε, μ, and y) in cosmic microwave data assuming that the SZ effect is positive (y>0). In this analysis, the magnitude of the space-dimension d with distortion of the space-dimension ε is defined by d=3+ε. The limits of μ and y are determined as |μ|<9×10^?5 (2σ) (μ=(?3.9±2.6)×10^?5 (σ)), |y|<5×10^?6 (2σ) (y=(2.0±1.4)×10^?6 (σ)), while the distortion of the space-dimension is |ε|<6×10^?5 (2σ) (ε=(?0.78±2.50)×10^?5 (σ)). The magnitudes of these three estimated limits are ordered as . The estimated limit of |y|<5×10^?6 appears to be related to re-ionization processes occurring at redshift z _ri ～10. We also present data analysis assuming a relativistic SZ effect.  相似文献   

Origin of tektites: Constraints from heavy noble gas concentrations     

Jun-ichi Matsuda  Kayo Matsubara  Christian Koeberl 《Meteoritics & planetary science》1993,28(4):586-589

Abstract— Heavy noble gas concentrations in tektites (splash-form type) are considerably lower than those in impact glasses. This can not be explained only by high formation temperatures for tektites, as might be expected from low concentrations of water and most volatile elements in tektites, and indicates that tektites solidified in an atmosphere with an ambient pressure of much less than 1 atm. The heavy noble gas concentrations may be an indicator of the height to which tektites were carried by the impact before they solidified.  相似文献   

He,Ne and Ar in peridotitic and eclogitic paragenesis diamonds from the Jwaneng kimberlite,Botswana—Implications for mantle evolution and diamond formation ages     

Masahiko Honda  David Phillips  Jeff W. Harris  Takuya Matsumoto 《Earth and Planetary Science Letters》2011,301(1-2):43-51

We have undertaken helium, neon and argon step-heating, isotopic analyses of eleven polycrystalline diamonds of known peridotite/eclogite paragenesis from the Jwaneng kimberlite pipe, Botswana. In contrast to the findings of crustal noble gases in framesites from the same kimberlite pipe (Honda et al., 2004. Unusual noble gas compositions in polycrystalline diamonds: preliminary results from the Jwaneng kimberlite, Botswana. Chem. Geol. 203, 347–358.), the Jwaneng polycrystalline diamonds appear to contain similar noble gas isotopic compositions (particularly Ne) to those representing a mantle source for MORBs. This implies that the Jwaneng polycrystalline diamonds may have formed in recent times, possibly close to the time of kimberlite emplacement at ~ 235 Ma. In contrast, Jwaneng framesites could be as old as gem diamonds (mineral inclusion ages of ~ 2.9 Ga). Furthermore, the data indicate that the sub-continental mantle lithosphere in the region has heterogeneous Ne isotopic compositions, or that these compositions changed over time from crustal Ne (as observed in the framesites) to MORB-like (as observed in the polycrystalline diamonds).  相似文献   

Fluid–rock interaction in the Qitianling granite and associated tin deposits, South China: Evidence from boron and oxygen isotopes     

Kui-Dong Zhao  Shao-Yong Jiang  Eizo Nakamura  Takuya Moriguti  Martin R. Palmer  Shui-Yuan Yang  Bao-Zhang Dai  Yao-Hui Jiang 《Ore Geology Reviews》2011,43(1):243-248

The behavior of boron and its isotopes in fluid-dominant processes and hydrothermal alteration of granites is examined using fresh and altered granite samples from the Qitianling granite and associated hydrothermal tin deposits in South China. Boron concentrations are highest in the fresh granite (37 ppm) and depleted as a result of two stages of fluid mobility and fluid–rock interaction within the granite. Constraints provided both by δ¹¹B and δ¹⁸O data suggest that the first stage was related to exsolution of aqueous fluids from the granite magma at a temperature of > 450 °C. This was followed by further boron depletion in the granite by hydrothermal circulation of meteoric water at lower temperatures (~ 350 °C) and low water/rock ratios. The sensitivity of coupled boron and oxygen isotope systematics to these processes suggests that they can provide valuable constraints on of fluid mobility in granite and associated mineralization.  相似文献   

Oceanic Rossby waves induced by the meridional shift of the ITCZ in association with ENSO events   总被引：1，自引：0，他引：1  

Hiroto Abe  Youichi Tanimoto  Takuya Hasegawa  Naoto Ebuchi  Kimio Hanawa 《Journal of Oceanography》2014,70(2):165-174

This study investigated the eastern Pacific Intertropical Convergence Zone (ITCZ) as an atmospheric forcing to the ocean by using various observed and reanalysis data sets over 29 years. Climatologically, a zonal band of positive wind stress curl (WSC) with a 10° meridional width was exhibited along the ITCZ. A southward shift of the positive WSC band during the El Niño phase induced a negative (positive) WSC anomaly along the northern (southern) portion of the ITCZ, and vice versa during the La Niña phase. This meridional dipole accounted for more than 25 % of interannual variances of the WSC anomalies (WSCAs), based on analysis of the period 1993–2008. The negative (positive) WSCA in the northern portion of the ITCZ during the El Niño (La Niña) phase was collocated with a positive (negative) sea surface height anomaly (SSHA) that propagated westward as a Rossby wave all the way to the western North Pacific. This finding indicates that this off-equatorial Rossby wave is induced by the WSCA around the ITCZ. Our analysis of a 1.5-layer reduced gravity model revealed that the Rossby waves are mostly explained by wind stress forcing, rather than by reflection of an equatorial Kelvin wave on the eastern coastal boundary. The off-equatorial Rossby wave had the same SSHA polarity as the equatorial Kelvin wave, and generation of a phase-preserving Rossby wave without the Kelvin wave reflection was explained by meridional movement of the ITCZ. Thus, the ITCZ acts as an atmospheric bridge that connects the equatorial and off-equatorial oceanic waves.  相似文献   

High frequency variability of current in the western channel of the Tsushima/Korea Straits     

Boonsoon Kang  Jong-Hwan Yoon  Takuya Nakakohara 《Journal of Oceanography》2012,68(5):615-624

The temporal characteristics and spatial structures of high frequency variability of the current in the western channel of the Tsushima/Korea Straits (TKS) are studied using ADCP data from 10?years along the cruise line of a regular ferry, “Camilla”, between Busan and Hakata. The eddy kinetic energy analysis shows that the high frequency variability has strong seasonal and spatial dependencies. From December to April, the variability is prominent in the entire western channel of the TKS. From July to October, it is enhanced only in the Korean coastal zone. The EOF analysis for the component of the high frequency currents normal to the ferry route illuminates three types of dominant modes, a transport mode and a vortex mode in the western channel during December–April, and a baroclinic coastal-trapped mode in the Korean coastal zone during July–October. The transport mode with a uniform current direction throughout the channel shows good correlation with the high frequency variability of the volume transport through the western channel with dominant time scales of 3.5 and 7?days. The vortex mode with alternating current directions across the channel explains well the variability of the eddy vorticity in the western channel with dominant time scales of 5–8?days. The baroclinic coastal-trapped mode in the Korean coastal zone has characteristics of both baroclinic Kelvin wave and topographic Rossby wave in the vertical current structure with dominant time scales of 14 and 32?days.  相似文献   

Correlating biostratigraphy and palaeoceanographic changes during late Quaternary at cold seeps with gas hydrate‐free areas of the Japan Sea using foraminifera paleoecology          下载免费PDF全文

Mahsa Saeidi Ortakand  Shiro Hasegawa  Ryo Matsumoto  Hiroki Matsuda 《Island Arc》2016,25(1):55-71

Late Quaternary foraminifera assemblages have been examined in two sediment cores (MD179‐3296 and MD179‐3317) from cold seep areas in the eastern margin of the Japan Sea, off Joetsu, Niigata Prefecture. Foraminifera assemblages in core MD179‐3296, which was located at the center of a pockmark on the Umitake Spur, show no evidence of methane flux and, especially in its upper portion, share the same paleo‐environmental history as other free gas hydrate areas of the Japan Sea. In comparison, in the core MD179‐3317 at the center of a pockmark at Joetsu Knoll, foraminiferal distributions were strongly affected by methane activities and, in the main part of the core, were deposited under local conditions. Three horizons were identified in this core, which are characterized by the high abundance value of Thalmannammina parkerae and might be related to methane flux due to sea level fall especially through late marine isotope stage (MIS) 3 and MIS 2.  相似文献   

Distribution of fault rocks in the fracture zone of the Nojima Fault at a depth of 1140 m: Observations from the Hirabayashi NIED drill core     

Kenta Kobayashi  Satoshi Hirano  Takashi Arai  Ryuji Ikeda  Kentaro Omura  Hiroyuki Sano  Takashi Sawaguchi  Hidemi Tanaka  Tomoaki Tomita  Naoto Tomida  Tatsuo Matsuda  Akiko Yamazaki 《Island Arc》2001,10(3-4):411-421

Abstract Characteristics of deformation and alteration of the 1140 m deep fracture zone of the Nojima Fault are described based on mesoscopic (to the naked eye) and microscopic (by both optical and scanning electron microscopes) observations of the Hirabayashi National Research Institute for Earth Science and Disaster Prevention (NIED) drill core. Three types of fault rocks; that is, fault breccia, fault gouge and cataclasite, appear in the central part of the fault zone and two types of weakly deformed and/or altered rocks; that is, weakly deformed and altered granodiorite and altered granodiorite, are located in the outside of the central part of the fault zone (damaged zone). Cataclasite appears occasionally in the damaged zone. Six distinct, thin foliated fault gouge zones, which dip to the south-east, appear clearly in the very central part of the fracture zone. Slickenlines plunging to the north-east are observed on the surface of the newest gouge. Based on the observations of XZ thin sections, these slickenlines and the newest gouge have the same kinematics as the 1995 Hyogo-ken Nanbu earthquake (Kobe earthquake), which was dextral-reverse slip. Scanning electron microscopy observations of the freeze-dried fault gouge show that a large amount of void space is maintained locally, which might play an important role as a path for fluid migration and the existence of either heterogeneity of pore fluid pressure or strain localization.  相似文献   

Examination of mineral assemblage and chemical composition in the fracture zone of the Nojima Fault at a depth of 1140 m: Analyses of the Hirabayashi NIED drill cores     

Tatsuo Matsuda  Takashi Arai  Ryuji Ikeda  Kentaro Omura  Kenta Kobayashi  Hiroyuki Sano  Takashi Sawaguchi  Hidemi Tanaka  Tomoaki Tomita  Naoto Tomida  Satoshi Hirano  Akiko Ymazaki 《Island Arc》2001,10(3-4):422-429

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Early diagenesis of fatty acids in lacustrine sediments—III. Changes in fatty acid composition in the sediments from a brackish water lake     

Hiromi Matsuda 《Geochimica et cosmochimica acta》1978,42(7):1027-1034

A 3-m sediment core taken from Lake Suigetsu, in which a shift from fresh to brackish water occurred about three hundred years ago, has been examined for variation with depth of organic carbon and fatty acids. From the difference in total amounts of sulphur between sediments under fresh and brackish water environments, the surface sediments above approximately 35 cm depth were deduced to be accumulated under a brackish water environment. The total contents of organic carbon and fatty acids, and percentage composition of fatty acids gave discontinuous profiles above and below the 35–40 cm sediment layer. At a depth of 12.5 cm, the distribution in chain length of the fatty acids changed from a unimodal (the predominance of C₁₂-C₁₈ over C₂₀-C₃₄) to a bimodal pattern, which was mirrored by the composition diversity index (CDI).Although the fatty acids in the surface sediments (0–40 cm) from Lake Suigetsu seemed to suffer milder degradation through microbial activity than those in a core (0–150 cm) from Lake Suwa, a freshwater eutrophic lake, both lacustrine sediments showed similar trends in the alteration of fatty acid composition with depth.  相似文献