The H i content of star-forming galaxies at z= 0.24     

Philip Lah  Jayaram N. Chengalur  Frank H. Briggs  Matthew Colless  Roberto De Propris  Michael B. Pracy  W. J. G. de Blok  Shinobu S. Fujita  Masaru Ajiki  Yasuhiro Shioya  Tohru Nagao  Takashi Murayama  Yoshiaki Taniguchi  Masafumi Yagi  Sadanori Okamura 《Monthly notices of the Royal Astronomical Society》2007,376(3):1357-1366

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P–T–t evolution of the Cycladic Blueschist Unit in Western Anatolia/Turkey: Geodynamic implications for the Aegean region     

Mete Çetinkaplan  Osman Candan  Roland Oberhänsli  Masafumi Sudo  Bénédicte Cenki-Tok 《Journal of Metamorphic Geology》2020,38(4):379-419

Eclogite and blueschist facies rocks occurring as a tectonic unit between the underlying Menderes Massif (MM) and the overlying Afyon Zone/Lycian Nappes and the Bornova Flysch Zone in western Anatolia represent the eastward continuation of the Cycladic Blueschist Unit (CBU) in Turkey. This high-P unit is attributed to the closure of the Pindos Ocean and consists of (a) a Triassic to Upper Cretaceous coherent series derived from passive continental margin sediments and (b) the tectonically overlying Upper Cretaceous Selçuk mélange with eclogite blocks embedded in a pelitic epidote-blueschist matrix. The coherent series has experienced epidote-blueschist facies metamorphism (490 ± 25°C/11.5 ± 1.5 kbar; 38 km depth). ⁴⁰Ar/³⁹Ar white mica and ²⁰⁶Pb/²³⁸U monazite dating of quartz metaconglomerate from coherent series yielded middle Eocene ages of 44 ± 0.3 and 40.1 ± 3.1 Ma for epidote-blueschist facies metamorphism, respectively. The epidote-blueschist facies metamorphism of the matrix of the Selçuk mélange culminates at 520 ± 15°C/13 ± 1.5 kbar, 43 km depth, and is dated at 57.5 ± 0.3–54.5 ± 0.1 Ma (⁴⁰Ar/³⁹Ar phengite). Eclogite facies metamorphism of the blocks (570 ± 30°C/18 ± 2 kbar, 60 km depth) is early Eocene and dated at 56.2 ± 1.5 Ma by ²⁰⁶Pb/²³⁸U zircon. Eclogites experienced a nearly isothermal retrogression (490 ± 40°C/~6 to 7 kbar) during their incorporation into the Selçuk mélange. The retrograde overprints of the coherent series (410 ± 15°C/7 ± 1.5 kbar from Dilek Peninsula and 485 ± 33°C/~6 to 7 kbar from Selçuk–Tire area) and the Selçuk mélange (510 ± 15°C/6 ± 1 kbar) are dated at 35.8 ± 0.5–34.3 ± 0.1 Ma by ⁴⁰Ar/³⁹Ar white mica and 31.6 ± 6.6 Ma by ²⁰⁶Pb/²³⁸U allanite dating methods, respectively. Regional geological constrains reveal that the contact between the MM and the CBU originally formed a lithosphere-scale transform fault zone. ⁴⁰Ar/³⁹Ar white mica age from the contact indicates that the CBU and the MM were tectonically juxtaposed under greenschist facies conditions during late Eocene, 35.1 ± 0.3 Ma.  相似文献   

Rock glaciers in the northern Japanese Alps: palaeoenvironmental implications since the Late Glacial     

Masafumi Aoyama 《第四纪科学杂志》2005,20(5):471-484

In order to determine the palaeoclimatic and palaeo‐permafrost conditions in the northern Japanese Alps in central Japan, the ages of rock glaciers were investigated by relative age dating techniques such as weathering‐rind thickness and Schmidt hammer measurements. The results of the relative age dating suggest that the formation of the investigated rock glaciers may have started during the early phase of the Late Glacial or around the onset of the Holocene. The lower limit of current discontinuous permafrost in the northern Japanese Alps, which is indicated by the terminus of the lowest active/inactive rock glacier, lies at 2530 m a.s.l., while that of discontinuous permafrost during the Late Glacial or early phase of the Holocene, which is indicated by the terminus of the lowest relict rock glacier, lies at 2220 m a.s.l. Therefore, the lower limit of discontinuous permafrost during these periods would have been at least about 300 m lower than that of the current discontinuous permafrost. Climatic and geomorphological conditions during the Late Glacial led to a change in the environment from a glacial environment to a periglacial (permafrost) environment in the current alpine zone of the northern Japanese Alps. A large number of cirques were deglaciated and several of them were occupied by active rock glaciers around the onset of the Holocene. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

High belowground biomass allocation in an upland black spruce (Picea mariana) stand in interior Alaska     

Kyotaro Noguchi  Masako Dannoura  Mayuko Jomura  Motoko Awazuhara-Noguchi  Yojiro Matsuura 《Polar Science》2012,6(1):133-141

The root system of forest trees account for a significant proportion of the total forest biomass. However, data is particularly limited for forests in permafrost regions. In this study, therefore, we estimated the above- and belowground biomass of a black spruce (Picea mariana) stand underlain with permafrost in interior Alaska. Allometric equations were established using 4–6 sample trees to estimate the biomass of the aboveground parts and the coarse roots (roots >5 mm in diameter) of P. mariana trees. The aboveground biomass of understory plants and the fine-root biomass were estimated by destructive sampling. The aboveground and coarse-root biomasses of the P. mariana trees were estimated to be 3.97 and 2.31 kg m^?2, respectively. The aboveground biomass of understory vascular plants such as Ledum groenlandicum and the biomass of forest floor mosses and lichens were 0.10 and 0.62 kg m^?2, respectively. The biomass of fine roots <5 mm in diameter was 1.27 kg m^?2. Thus, the above- and belowground biomasses of vascular plants in the P. mariana stand were estimated to be 4.07 and 3.58 kg m^?2, respectively, indicating that belowground biomass accounted for 47% of the total biomass of vascular plants. Fine-root biomass was 36% of the total root biomass, of which 90% was accumulated in the surface organic layer. Thus, this P. mariana stand can be characterized as having extremely high belowground biomass allocation, which would make it possible to grow on permafrost with limited soil resource availability.  相似文献   

Latitudinal and downcore (0–750 ka) changes in n-alkane chain lengths in the eastern equatorial Pacific     

Keiji Horikawa  Masafumi Murayama  Masao Minagawa  Yoshihisa Kato  Takuya Sagawa 《Quaternary Research》2010,73(3):573-582

The n-alkane C₃₁/(C₂₉ + C₃₁) ratios from surface sediments in the eastern equatorial Pacific (EEP) exhibit higher values to the north and lower values to the south across the southern edge (2–4°N) of the Intertropical Convergence Zone (ITCZ). Since plants tend to synthesize longer chain length n-alkanes in response to elevated temperature and/or aridity, the higher C₃₁/(C₂₉ + C₃₁) ratios at northern sites suggest a higher contribution of vegetation under hot and/or dry conditions. This is consistent with the observation that northern sites receive higher levels of plant waxes transported by northeasterly trade winds from northern South America, where hot and dry conditions prevail. Furthermore, from a sediment core covering the past 750 ka (core HY04; 4°N, 95°W) we found that C₃₁/(C₂₉ + C₃₁) ratios exhibit a long-term decrease from MIS (marine oxygen isotope stage) 17 to 13. During this period, the zonal SST (sea-surface temperature) gradient in the equatorial Pacific increased, suggesting an increase in Walker circulation. Such intensified Walker circulation may have enhanced moisture advection from the equatorial Atlantic warm pool to the adjacent northern South America, causing arid regions in northern South America to contract, which may explain long-term decrease in n-alkane chain lengths.  相似文献   

Stormflow generation involving pipe flow in a zero‐order basin of Peninsular Malaysia     

J. N. Negishi  S. Noguchi  R. C. Sidle  A. D. Ziegler  Abdul Rahim Nik 《水文研究》2007,21(6):789-806

Hydrological responses in a zero‐order basin (ZOB), a portion of whose discharge emerged via preferential flow through soil pipes, were examined over a 2‐year period in Peninsular Malaysia to elucidate primary stormflow generation processes. Silicon (Si) and specific conductance (EC) in various runoff components were also measured to identify their sources. ZOB flow response was dependent on antecedent precipitation amount; runoff increased linearly with precipitation during events >20 mm in relatively wet antecedent moisture conditions. Runoff derived from direct precipitation falling onto saturated areas accounted for <0·2% of total ZOB flow volume during the study period, indicating the predominance of subsurface pathways in ZOB flow. ZOB flow (high EC and low Si) was distinct from perennial baseflow via bedrock seepage (low EC and high Si) 5 m downstream of the ZOB outlet. Pipe flow responded quickly to ZOB flow rate and was characterized by a threshold flow capacity unique to each pipe. Piezometric data and pipe flow records demonstrated that pipes located deeper in the soil initiated first, followed by those at shallower depths; initiation of pipe flow corresponded to shallow groundwater rise above the saprolite‐soil interface. Chemical signatures of pipe flow were similar to each other and to the ZOB flow, suggesting that the sources were well‐mixed soil‐derived shallow groundwater. Based upon the volume of pipe flow during storms, the combined contribution of the pipes monitored accounted for 48% of total ZOB flow during the study period. Our results suggest that shallow groundwater, possibly facilitated by preferential flow accreted above the saprolite–soil interface, provides dominant stormflow, and that soil pipes play an important role in the rapid delivery of solute‐rich water to the stream system. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Large-Scale Mapping Observations of the C i (3P1-3P0) and CO (J = 3-2) Lines toward the Orion A Molecular Cloud     

Ikeda M  Maezawa H  Ito T  Saito G  Sekimoto Y  Yamamoto S  Tatematsu K  Arikawa Y  Aso Y  Noguchi T  Shi SC  Miyazawa K  Saito S  Ozeki H  Fujiwara H  Ohishi M  Inatani J 《The Astrophysical journal》1999,527(1):L59-L62

Large-scale mapping observations of the 3P1-3P0 fine-structure transition of atomic carbon (C i, 492 GHz) and the J=3-2 transition of CO (346 GHz) toward the Orion A molecular cloud have been carried out with the Mount Fuji submillimeter-wave telescope. The observations cover 9 deg2 and include the Orion Nebula M42 and the L1641 dark cloud complex. The C i emission extends over almost the entire region of the Orion A cloud and is surprisingly similar to that of 13CO (J=1-0). The CO (J=3-2) emission shows a more featureless and extended distribution than C i. The C i/CO (J=3-2) integrated intensity ratio shows a spatial gradient running from the north (0.10) to the south (1.2) of the Orion A cloud, which we interpret as a consequence of the temperature gradient. On the other hand, the C i/13CO (J=1-0) intensity ratio shows no systematic gradient. We have found a good correlation between the C i and 13CO (J=1-0) intensities over the Orion A cloud. This result is discussed on the basis of photodissociation region models.  相似文献   

Resistivity exploration for altered zone at otake geothermal area — Japan     

T. Noguchi  S. Onodera 《Bulletin of Volcanology》1969,33(1):205-227

Geothermal electric power plant with a capacity of 10 mw has been now constructed by the Kyushu Electric Power Co. Ltd. at Otake, northern part of the Kyushu Island. Resistivity exploration, one of geophysical prospecting applied to this field in order to investigate the subsurface structure accompanied with natural steams, indicated low resistivity layer corresponding to altered zone of andesite due to hydrothermal agents. For the rapid interpretation of resistivity sounding curves, a method of calculating the standard curve for the multiple layered earth is developed in the utilization of an electronic digital computer. Some examples to show the application of this method are given, and tinally the result is described of resistivity measurement at Otake geothermal area.  相似文献   

Short-range prediction experiments of the Kuroshio path variabilities south of Japan   总被引：1，自引：0，他引：1  

Norihisa Usui  Hiroyuki Tsujino  Yosuke Fujii  Masafumi Kamachi 《Ocean Dynamics》2006,56(5-6):607-623

Assimilation and prediction experiments of the Kuroshio path variability south of Japan were conducted to investigate the predictability of the Kuroshio path. The assimilation and prediction system is composed of an eddy-resolving model and a three-dimensional variational analysis scheme with vertical coupled temperature–salinity empirical orthogonal function modes. The sea surface height (SSH) variability and the variations of the Kuroshio path of the assimilation fields are in good agreement with those observed. The results of the assimilation are then used as the initial conditions for 138 cases of 90-day prediction experiments conducted from 1993 to 2004. The predictive limit of our system is assessed by the SSH anomaly in the assimilation field and is found to be around 40–60 days, which is much longer than that of the persistence. The prediction results show good performance in the transition stage from a straight to a meandering path. For example, a large meandering event that occurred in August 2004 is successfully predicted in a 2-month forecast. Two types of failure cases are investigated. One is a case where the eastward propagation speed of the meander is faster than a real state. The dynamical response of the model to the assimilation revealed that an initial shock, caused by the dynamically unbalanced initial condition, induces the fast eastward propagation of the meander. The other case exhibits an unrealistic meander. In this case, a cold anomaly at an intermediate layer in the initial condition grows rapidly and results in the unrealistic meander. This implies that the Kuroshio path south of Japan has a chaotic nature. These facts revealed by the failure cases give us some insight for improving the predictive skill of the Kuroshio path variability.  相似文献   

Discovery of a large-scale clumpy structure around the Lynx supercluster at z∼ 1.27     

Fumiaki Nakata  Tadayuki Kodama  Kazuhiro Shimasaku  Mamoru Doi  Hisanori Furusawa  Masaru Hamabe  Masahiko Kimura  Yutaka Komiyama  Satoshi Miyazaki  Sadanori Okamura  Masami Ouchi †  Maki Sekiguchi  Yoshihiro Ueda  Masafumi Yagi  Naoki Yasuda 《Monthly notices of the Royal Astronomical Society》2005,357(4):1357-1362

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