Investigation of ULF Seismo-Magnetic Phenomena in Kanto, Japan During 2000–2010: Case Studies and Statistical Studies     

Katsumi Hattori  Peng Han  Chie Yoshino  Febty Febriani  Hiroki Yamaguchi  Chieh-Hung Chen 《Surveys in Geophysics》2013,34(3):293-316

In order to clarify the ultra low frequency (ULF) seismo-magnetic phenomena, a sensitive geomagnetic network has been installed in Kanto, Japan. In this study, we have analyzed geomagnetic data observed during the past decade in Izu and Boso Peninsulas. Energy of ULF geomagnetic signals at the frequency around 0.01 Hz has been investigated by wavelet transform analysis. To identify anomalous changes in ionospheric disturbances, the station Memabutsu has been chosen as a reference station. Case studies of magnitude 6 class earthquakes have demonstrated that there are unusual geomagnetic energy enhancements in the vertical component before the main shocks. Statistical studies by superposed epoch analysis have indicated that, before a sizeable earthquake, there are clearly higher probabilities of ULF anomalies than after the earthquake: statistical results of daily counts were found significant at about 3–4 weeks before, 1 week before, few days before, and 1 day after the event for Seikoshi station in Izu and around 2 weeks before, few days before, and 1 day after the event for Kiyosumi station in Boso, respectively.  相似文献   

泰国北部Inthanon带外来硅质岩块的中、晚二叠世放射虫：对与古特提斯消减有关的混杂岩形成时代的约束     

Yoshihito KAMATA  Hidetoshi HARA  Katsumi UENO  Apsorn SARDSUD  Thasinee CHAROENTITIRAT  Punya CHARUSIRI  Ken-ichiro HISADA 《地球学报》2012,33(S1):36-37

The Inthanon Zone of Northern Thailand, origi-nally proposed by Barr and Macdonald (1991), is characterized by the occurrence of Paleo-Tethyan pe-lagic sediments including Carboniferous–Permian seamount-type carbonate associated with oceanic ba-saltic rocks and Middle Devonian–Middle Triassic radiolarian chert (Ueno, 1999; Ueno and Hisada, 2001; Ueno and Charoentitirat, 2011). These pelagic rocks have been mainly studied from the viewpoint of bio-stratigraphy to clarify the duration of their deposition. These studies concluded the Paleo-Tethys to be a vast ocean basin once existed between the Indochina and Sibumasu continental blocks during Devo-nian–Triassic times.  相似文献   

泰国北部三叠系Lampang群Doi Long组的有孔虫组合与沉积环境     

Akira MIYAHIGASHI  Katsumi UENO  Thasinee CHAROENTITIRAT  Yoshihito KAMATA 《地球学报》2012,33(S1):45-49

A rich foraminiferal assemblage, consisting of abundant Aulotortus sinuosus and A. tumidus in association with Lamelliconus multispirus, Endoteba ex gr. controversa, E. ex gr. badouxi, Endotebanella kocaeliensis, Endotriada tyrrhenica, Endotriadella wirzi, Malayspirina fontainei, Ammobaculites rhaeticus, Diplotremina astrofimbriata, Agathammina austroalpina, and others, was found in the Doi Long Formation of the Triassic Lampang Group, Northern Thailand. These foraminifers suggest that the formation is referable to the Carnian (early Late Triassic), which is consistent with the age estimated by ammonoids. In microfacies, peloidal grainstone, bioclastic grainstone, sponge-microbial boundstone, and oolitic grainstone were recognized in the Doi Long Formation. Based on microfacies, three depositional facies, the lagoon facies, reef facies, and shoal facies, are recognized in this formation. These lines of evidence are suggestive that the Doi Long Formation was deposited in a reef or bank setting rather than a ramp setting.  相似文献   

Metamorphic and cooling history of the Shimanto accretionary complex,Kyushu, Southwest Japan: Implications for the timing of out‐of‐sequence thrusting     

Hidetoshi Hara  Katsumi Kimura 《Island Arc》2008,17(4):546-559

Illite crystallinity, K–Ar dating of illite, and fission‐track dating of zircon are analyzed in the hanging wall (Sampodake unit) and footwall (Mikado unit) of a seismogenic out‐of‐sequence thrust (Nobeoka thrust) within the Shimanto accretionary complex of central Kyushu, southwest Japan. The obtained metamorphic temperatures, and timing of metamorphism and cooling, reveal the tectono‐metamorphic evolution of the complex, and related development of the Nobeoka thrust. Illite crystallinity data indicate that the Late Cretaceous Sampodake unit was metamorphosed at temperatures of around 300 to 310°C, while the Middle Eocene Mikado unit was metamorphosed at 260 to 300°C. Illite K–Ar ages and zircon fission‐track ages constrain the timing of metamorphism of the Sampodake unit to the early Middle Eocene (46 to 50 Ma, mean = 48 Ma). Metamorphism of the Mikado unit occurred no earlier than 40 Ma, which is the youngest depositional age of the unit. The Nobeoka thrust is inferred to have been active during about 40 to 48 Ma, as the Sampodake unit started its post metamorphic cooling after 48 Ma and was thrust over the Mikado unit at about 40 Ma along the Nobeoka thrust. These results indicate that the Nobeoka thrust was active for more than 10 million years.  相似文献   

Lopingian (Late Permian) foraminiferal faunal succession of a Paleo-Tethyan mid-oceanic carbonate buildup: Shifodong Formation in the Changning–Menglian Belt, West Yunnan, Southwest China     

Katsumi  Ueno  Satoe  Tsutsumi 《Island Arc》2009,18(1):69-93

This paper deals with a Lopingian (Late Permian) foraminiferal faunal succession of the Shifodong Formation in the Changning–Menglian Belt, West Yunnan, Southwest China, which has been geologically interpreted as one of the closed remnants in East Asia of the Paleo‐Tethys Ocean. The Shifodong Formation is the uppermost stratigraphic unit in thick Carboniferous–Permian carbonates of the belt. These carbonates rest upon bases consisting of oceanic island basalt and are widely accepted as having a Paleo‐Tethyan mid‐oceanic (seamount‐ or oceanic plateau‐top) origin. Sixteen taxa of fusuline foraminifers and 37 taxa of smaller (non‐fusuline) foraminifers are recognized from the type section of the Shifodong Formation located in the Gengma area of the northern part of the Changning–Menglian Belt. Based on their stratigraphic distribution, three fusuline zones can be established in this section: they are, in ascending order, the Codonofusiella cf. C. kwangsiana Zone, Palaeofusulina minima Zone, and Palaeofusulina sinensis Zone. These three biozones are respectively referable to the Wuchiapingian, early Changhsingian, and late Changhsingian, of which the Wuchiapingian is first recognized in this study in the Changning–Menglian mid‐oceanic carbonates. The present study clearly demonstrates that the foraminiferal fauna in a Paleo‐Tethyan pelagic shallow‐marine environment still maintained high faunal diversity throughout the almost entire Lopingian, although the very latest Permian fauna in the upper part of the Palaeofusulina sinensis Zone of the Shifodong section records a sudden decrease in both faunal diversity and abundance. Moreover, the Shifodong faunas are comparable in diversity with those observed in circum‐Tethyan shelves such as South China. The present Paleo‐Tethyan mid‐oceanic foraminiferal faunas are definitely more diversified than coeval mid‐oceanic Panthalassan faunas, which are typically represented by those from the Kamura Limestone in a Jurassic accretionary complex of Southwest Japan. It is suggestive that the Paleo‐Tethyan mid‐oceanic buildups presumably supplied a peculiarly hospitable habitat for foraminiferal faunal development in a pelagic paleo‐equatorial condition.  相似文献   

Mineralogy and Isotope Geochemistry of Active Submarine Hydrothermal Field at Suiyo Seamount, Izu–Bonin Arc, West Pacific Ocean     

Katsumi Marumo    Tetsuro Urabe    Akiko Goto  Yoshinori Takano  Miwako Nakaseama 《Resource Geology》2008,58(3):220-248

This report presents mineralogical, geochemical and isotopic data on samples obtained using the Benthic Multi‐coring System (BMS) to drill a submarine hydrothermal deposit developed in a caldera on the summit of the Suiyo Seamount in the Izu–Bonin Island Arc, south of Japan. This deposit is regarded as the first example of Kuroko‐type sulfide mineralization on a volcano at the volcanic front of an island arc. The mineralization and hydrothermal alteration below the 300 × 150‐m area of active venting was investigated to depths of 2–9 m below the sea floor. Drilling beneath the area of active venting recovered a sequence of altered volcanic rocks (dacite lavas, pyroclastic rocks of dacite–rhyolite compositions and pumice) associated with sulfide veining and patches/veins of anhydrite. No massive sulfide was found, however, and the subsea‐floor mineralization to 10 m depth is dominated by anhydrite and clay minerals with some sulfides. Sulfide‐bearing samples contained high Au (up to 42 ppm), Ag (up to 263 ppm), As (up to 1550 ppm), Hg (up to 55 ppm), Sb (up to 772 ppm), and Se (up to 24 ppm). Electron probe microanalyzer indicated that realgar, orpiment, and mimetite were major As‐bearing minerals. The sulfides were also characterized by high Zn (>10%) compared to Cu (<6.3%) and Pb (<0.6%). The δ²⁰²Hg/¹⁹⁸Hg, δ²⁰²Hg/¹⁹⁹Hg and δ²⁰²Hg/²⁰⁰Hg of the sulfide‐bearing dacite samples and a sulfide chimney decreased with increasing Hg/Zn concentration ratio. The variation of the δ²⁰²Hg/¹⁹⁸Hg ranged from ?2.8 to +0.5‰ to relative to S‐HG02027. The large range of these δ²⁰²Hg/¹⁹⁸Hg was greater than might be expected for such a heavy element and may be due to a predominance of kinetic effects. The variation of δ²⁰²Hg/¹⁹⁸Hg of sulfide‐bearing dacite samples suggested that light Hg isotope in the vapor mixed with oxygenated seawater near sea floor during mineralization. Lead isotope ratios of the sulfide were very similar to those of the dacite lava, suggesting that lead is of magmatic origin. The ⁸⁷Sr/⁸⁶Sr ratio (0.70872) of anhydrite was different from that of the dacite lava, and suggests an Sr derivation predominantly from seawater. Hydrothermal alteration of the dacite in the Suiyo hydrothermal field was characterized by Fe‐sulfides, anhydrite, barite, montmorillonite, chlorite/montmorillonite mixed‐layer minerals, mica, and chlorite with little or no feldspar or cristobalite. Hydrothermal clay minerals changed with depth from montmorillonite to chlorite/montmorillonite mixed‐layer minerals to chlorite and mica. Hydrogen isotope ratios of chlorite/montmorillonite and mixed‐layer, mica‐chlorite composites obtained below the active venting sites ranged from ?49 to ?24‰, suggesting seawater as the dominant fluid causing alteration. Oxygen isotope ratios of anhydrite ranged from 9.2 to 10.4‰ and anhydrite formation temperatures were calculated to be 188–207°C. Oxygen isotope ratios ranged from +5.2 to +9.2‰ for montmorillonite, +3.2 to +4.5‰ for chlorite/montmorillonite mixed‐layer minerals, and +2.8 to +3.8‰ in mixtures of chlorite and mica. The formation temperatures of montmorillonite and of the chlorite–mica mixture were 160–250°C and 230–270°C, respectively. The isotope temperatures for clay minerals (220–270°C) and anhydrite (188°C) were significantly lower than the borehole temperature (308.3°C) measured just after the drilling, suggesting that temperature at this site is now higher than when clay minerals and anhydrite were formed.  相似文献   

Choice of conodont Idiognathodus simulator （sensu stricto） as the event marker for the base of the global Gzhelian Stage （Upper Pennsylvanian Series,Carboniferous System）   总被引：3，自引：0，他引：3  

Philip H. Heckel  ;Aleksandr S. Alekseev  ;James E. Barrick  ;Darwin R. Boardman  ;Natalya V. Goreva  ;Tatiana N. Isakova  ;Tamara I. Nemyrovska  ;Katsumi Ueno  ;Elisa Villa  ;David M. Work 《《幕》》2008,31(3):319-325

We propose that the level at which the conodont species Idiognathodus simulator （Ellison 1941） （sensu stricto） first appears be selected to mark the base of the Gzhelian Stage, because we believe that this is the optimal level by which this boundary can be correlated. This taxon has a short range and a wide distribution, as shown by correlation of glacial-eustatic cyclothems across the Kasimovian-Gzhelian boundary interval among Midcontinent North America and the Moscow and Donets basins of eastern Europe, based on scale of the cyclothems along with several aspects of biostrati- graphy. Outside of these areas, I. simulator （sensu stricto） is known also from other parts of the U.S., and is reported from the southern Urals and south-central China in its expected position between other widespread taxa. Its first appearance is consistent with the current ammonoid placement of the boundary （first appearance of Shumardites cuyleri）, and it is also compatible with certain aspects of the distribution of Eurasian fusulinid faunas （e.g., lectotype ofRauserites rossicus）.  相似文献   

Model Simulations of Carbon Sequestration in the Northwest Pacific by Direct Injection     

Katsumi?MatsumotoEmail author  Bryan?K.?Mignone 《Journal of Oceanography》2005,61(4):747-760

The direct disposal of CO₂ into the ocean interior represents a possible means to help mitigate rising levels of atmospheric CO₂. Here, we use three different versions of an ocean general circulation model (OGCM) to simulate the direct injection of liquid CO₂ near Tokyo. Our results confirm that direct injection can sequester large amounts of CO₂ from the atmosphere when disposal is made at sufficient depth (80–100% of the carbon injected at 3000 m remains in the ocean after 500 years) but show that the calculated efficiency is rather sensitive to the choice of physical model. Moreover, we show, for the first time in an OGCM and under a reasonable set of economic assumptions, that sequestration effectiveness is quite high for even shallow injections. However, the severe acidification that accompanies injection and the impossibility of effectively monitoring injected plumes argue against the large-scale viability of this technology. Our coarse-grid models show that injection at the rate of 0.1 Pg-C/yr lowers pH near the site of injection by as much as 0.7–1.0 pH-unit. Such pH anomalies would be much larger in more finely gridded models (and in reality) and have potential to severely harm deep-sea organisms. We also show that, after several hundred years, one would effectively need to survey the entire ocean in order to accurately verify the inventory of injected carbon. These results suggest that while retention may be sufficient to justify disposal costs, other practical problems will limit or at best delay widespread deployment of this technology.  相似文献   

Chemical speciation of trace metals in seawater: Implication of particulate trace metals     

Katsumi Hirose 《Marine Chemistry》1990,28(4)

Chemical speciation of particulate metals in seawater was examined theoretically. Mass balance considerations showed that the apparent conditional stability constant, defined for organically binding metals in suspended particles, coincides with the conditional stability constant determined for the corresponding metal-organic complexes dissolved in seawater. This hypothesis suggests that some metals, which are present as organic complexes (e.g. copper), are directly associated with particulate organic matter. Metals, whose free ion is buffered by organic and/or inorganic ligands, may be used as indicators of the presence of particulate organic matter in the marine environment.  相似文献   

Early Permian ammonoids from the Kaeng Krachan Group of the Phatthalung-Hat Yai area, southern peninsular Thailand   总被引：1，自引：1，他引：1  

Masayuki Fujikawa  Katsumi Ueno  Apsorn Sardsud  Wirote Saengsrichan  Yoshihito Kamata  Ken-ichiro Hisada 《Journal of Asian Earth Sciences》2005,24(6):739

An Early Permian small ammonoid fauna consisting of Neocrimites sp., Agathiceras suessi Gemmellaro, A. girtyi Böse, Agathiceras? sp., and Miklukhoceras sp. was found in nodules of a fine sandstone bed exposed in the Phatthalung-Hat Yai area of southern peninsular Thailand. The ammonoid-bearing bed belongs stratigraphically to the uppermost part of the Kaeng Krachan Group, which is essentially a clastic-dominant, Late Carboniferous (?) to Early Permian stratigraphic unit, widely distributed in western and peninsular Thailand. This ammonoid fauna is considered to be of Bolorian (Kungurian) age and includes Agathiceras girtyi Böse, which is described for the first time from Thailand. The present discovery of Bolorian ammonoids suggests that the uppermost part of the Kaeng Krachan Group is slightly younger than previously considered and around the latest Early Permian. This further implies that the continental margin environment of the Sibumasu Block drastically changed at around Bolorian time from a cool, clastic-dominant shelf condition to a temperate to subtropical, carbonate platform due to rapid northward drift after middle Artinskian rifting.  相似文献