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51.
Radiolarian-bearing conglomerate from the Hayang Group, the Kyongsang Supergroup, southeastern Korea 总被引:1,自引:0,他引:1
T. Mitsugi K. Ishida B. -G. Woo K. -H. Chang S. -O. Park H. Hirano 《Journal of Asian Earth Sciences》2001,19(6):87
The non-marine Cretaceous Kyongsang Supergroup, which is divided into the Sindong, the Hayang and the Yuchon groups, is widely distributed in southeastern Korea. Radiolarian-bearing pebbles are collected from the conglomerates of the Kumidong and the Kisadong formations of the Hayang Group. The age of radiolarian fossils range from Late Permian to Middle Jurassic. In Korea, Permian to Middle Jurassic marine chert beds are not exposed. The directions of paleocurrents of the Kumidong and the Kisadong formations are mainly from the northeast to southwest. During Cretaceous time, the Mino-Tamba Belt, within which Permian to Middle Jurassic chert beds are exposed, is suggested to have been located northeast of the Kyongsang Basin. The radiolarian faunas of the Hayang Group are similar to those of the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan (e.g. the Ashio Belt). The provenance of the radiolarian-bearing pebbles collected from the Kumidong and the Kisadong formations is interpreted to be the Mino-Tamba Belt and other associated Mesozoic accretionary belts in Japan. 相似文献
52.
Summary Core discing was typically observed in cores recovered from near horizontal holes drilled in Palaeogene sandstones at a depth of 1055 m in the Horonai colliery, Hokkaido, Japan. We have observed disc- and ring-like cores and measured in situ stress where they were recovered. We compared the measured stress state with an empirical criterion of core discing based on Obert and Stephenson (1965) and a theoretical criterion based on Sugawara et al. (1978) and Ishida and Saito (1989). Consequently, we found that disc-like cores were recovered under lower stress state than predicted by both criteria. The stress state where ring-like cores were recovered satisfied the empirical criterion, however, it was below the critical stress state according to the theoretical criterion. These discrepancies indicate that existing stress criteria are not satisfactory and that further experimental, theoretical and field investigations are needed. 相似文献
53.
Near-surface wind velocities were measured on an array of anchored spar buoys in the East China Sea in February 1975 as a part of the Japanese AMTEX '75 (Air Mass Transformation Experiment), a subprogram of GARP. These data were used to determine the effects of atmospheric convection associated with mesoscale convective cells (MCC) on near-surface winds over the ocean. When MCC were present, a peak occurred in the near-surface wind spectrum in the so-called spectral gap. 相似文献
54.
Ishimaru Satoko; Arai Shoji; Ishida Yoshito; Shirasaka Miki; Okrugin Victor M. 《Journal of Petrology》2007,48(2):395-433
55.
Simultaneous In Situ Analysis of Carbon and Nitrogen Isotope Ratios in Organic Matter by Secondary Ion Mass Spectrometry
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Akizumi Ishida Kouki Kitajima Kenneth H. Williford Michael L. Tuite Takeshi Kakegawa John W. Valley 《Geostandards and Geoanalytical Research》2018,42(2):189-203
An in situ measurement method for simultaneous determination of carbon and nitrogen isotope ratios in organic matter was developed by secondary ion mass spectrometry with a spatial resolution of ~ 12 μm. Secondary ion intensities of 12C?2, 12C13C?, 12C14N? and 12C15N? were simultaneously measured by three Faraday cups and one electron multiplier. Ions of 12C2H? were measured to monitor hydride interferences and to correct for mass bias. The analytical precisions of δ13C and δ15N values of a reference material (UWLA‐1 anthracite) were 0.16‰ and 0.56‰, respectively (2s). A negative correlation was observed between the mass bias of carbon and 12C2H?/12C?2 ratios of examined reference materials. In contrast, there was no correlation between mass bias and hydrogen concentration for nitrogen. The δ13CVPDB and δ15NAir values of twenty‐two individual globules of organic matter, found in carbonate rock of the 1878 Ma Gunflint Formation, were determined by the new procedure, ranging from ?33.8‰ to ?33.3‰ and +4.2‰ to 5.8‰, respectively. Means of δ13CVPDB and δ15NAir values, ?33.5 ± 0.25‰ and +5.2 ± 0.81‰, are consistent with reported values from bulk sample analysis within analytical precision. 相似文献
56.
Keisuke Ishida Yasuyuki Tsujino Takeshi Kozai Tadashi Sato Francis Hirsch 《中国科学D辑(英文版)》2009,52(12):1910-1923
The last appearance datum of the radiolarian Kilinora spiralis is recorded above the first appearance datum of the ammonite Ataxioceras (A.) kurisakense in the Todoro Section of the Kurisaka Formation, Southern Kurosegawa Terrane, Shikoku, SW Japan. The constraint by ammonite
age prolongs the range of the Kilinora spiralis Zone, a remarkable Jurassic radiolarian zone in Japan-NW Pacific region, into the lower Kimmeridgian. The direct correlation
of the Kilinora spiralis zone with the Late Jurassic ammonite faunal succession in the Kurisaka Formation will provide a clue to the still pending
chronological difference between European and North American radiolarian zones. 相似文献
57.
Tomoaki Morishita Yoshito Ishida Shoji Arai Miki Shirasaka 《Geostandards and Geoanalytical Research》2005,29(1):107-122
To understand and/or avoid small-scale chemical heterogeneities within geological materials prepared as normal thin sections, in situ multiple trace element determination coupled with the simultaneous microscopic observation of the sample during analysis is preferable. We have examined fifty trace elements in thin (< 30 μm) layers of the NIST SRM 614 and 616 glass reference materials by LA-ICP-MS using different pit diameters and internal standard elements (Ca and Si). Compositional heterogeneities of Tl, Bi, As and Cd were found in NIST SRM 614 and 616 at the spatial resolution of ca. 10 0 μm. Except for these elements, the RSDs of six determinations for most elements were better than 10% in NIST SRM 614 when ablation diameters were < 50 μm. The measured concentrations for most elements in NIST SRM 614 and 616 agree with previous values in the literature at the 95% confidence level with the exception of W and Bi. New LA-ICP-MS data for K, As and Cd are also reported. The results support the view that the latest LA-ICP-MS is a powerful and flexible analytical technique for the determination of multiple ultra-trace element compositions in geological materials prepared as normal thin sections of the type that has been used for polarising optical microscopic observations since the end of the 19th century. 相似文献
58.
We have analyzed the sidereal diurnal variation of cosmic rays, using 620 station-years of neutron monitor data during the period 1958–1979. The sidereal variation averaged over the period for all the stations in the Northern Hemisphere is different from the corresponding variation in the Southern Hemisphere. The difference is statistically significant and can be identified with the spurious sidereal variation produced from the stationary anisotropy of solar origin, responsible for the solar semi-diurnal variation. The variation common to both hemispheres is also exceptionally significant from the statistical point of view and could be regarded as being due to a uni-directional galactic anisotropy. This variation has an amplitude of 0.0204 ± 0.0015% and a phase of 6.8 ± 0.3 h and is clearly different from that ( ~ 0.05%, 0 ~ 3 h) observed in the high rigidity region (500 ~ 104 GV). The physical meaning of the variation is discussed from the standpoint of the heliomagnetospheric modulation of galactic anisotropy. 相似文献
59.
Chiyuki Sassa Kouichi Kawaguchi Yuichi Hirota Minoru Ishida 《Deep Sea Research Part I: Oceanographic Research Papers》2007,54(12):2181-2193
We describe the day–night vertical distribution patterns of 18 species or types of myctophid fish larvae at the transforming stage based on discrete depth sampling from the surface down to 1000-m depth in the subtropical–tropical western North Pacific. A total of 551 transforming stage larvae were collected at the 19 sampling stations. Except for the Diaphus species and Notolychnus valdiviae, all of the transforming stage larvae (including genera Benthosema, Bolinichthys, Centrobranchus, Ceratoscopelus, Diogenichthys, Hygophum, Lampanyctus, Lobianchia, Myctophum, Symbolophorus, and Triphoturus) were collected in the lower mesopelagic zone from 600- to 900-m depth during both day and night, showing no diel vertical migration (DVM). On the contrary, the Diaphus species and N. valdiviae larvae undergo DVM during the transforming stage, occurring below 200-m layer during the daytime and migrating up to the upper 150-m layer at night, i.e., they show earlier adaptation to juvenile–adult behaviors. Most myctophid fish larvae are known to undertake substantial ontogenetic vertical migration (OVM) from the epipelagic to mesopelagic zones during their early life stage. Although considerable sampling effort was carried out in this study, transforming larvae, except for the above two migratory ones, were not collected in the epipelagic and upper mesopelagic zones, strongly suggesting that their sinking speed would be high. It would be advantageous for survival to spend their highly vulnerable transforming stage in the lower mesopelagic zone, where predation pressures are lower and physical conditions are more stable than in the upper layers. 相似文献
60.
The revision of the Middle and early Late Triassic conodonts in the Nogami (1968) collection from the NW Malaya Kodiang Limestone Formation provides clues to the multi-element reconstruction of Triassic Gondolellacea. Septi- to octomembrate multi-elements characterize the families Gondolellidae and Gladigondolellidae nov. fam. The distribution of cratognathodiform and ozarkodiniform P2 elements supports the hypothesis of sexual dimorphism in Gladigondolella rather than that of two genera. Pseudofurnishius murcianus confers a Southern Tethyan low latitude character to the Kodiang Limestone, a part of the Cimmerian string of terranes that in Triassic times formed a diagonal partition between the gradually closing Paleo-Tethys and the accordingly widening Neo-Tethys. Our findings suggest that such a realm stretched from the Southern Alps (Dinarids) in the West to Malaya (Shan Thai Terrane) in the East. Only the Eastern edge collided with Eurasia in the Late Triassic, forming the platform of Sundaland. Consequently, the Paleo-Tethys closure remained limited to SE Asia, while a substantial Paleo-Tethys still existed in Western direction, ending up in the Pindos and Vardar oceans. The Jurassic Neo-Tethys ocean extended south of the consolidated SE Asia block and Cimmerian string of terranes. 相似文献