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111.
Abstract Recent advanced chronological studies for the Tertiary volcanic rocks from the Northeast (NE) Japan arc revealed three volcanic fronts which differed in temporal and spatial distribution. These fronts were (i) the Matsumae-Shizukuishi-Shiogama line of 22–25 Ma which is obliquely across the Quaternary volcanic front (QVF); (ii) the Tomari-Shiogama line of 13–16 Ma which exists 30–50 km east of the QVF and (iii) a line of 0–8 Ma which is the same as the QVF. The first shifting of the 22–25 Ma line to the 13–16 Ma one was due to the counterclockwise rotation of the NE Japan arc during 20–12 Ma as proposed by Otofuji et al . (1985), and the second shifting of the 13–16 Ma line to the 0–8 Ma line could have contributed to a decrease in the dip of the slab of the Pacific plate which subducted beneath the NE Japan arc during 13–8 Ma. 相似文献
112.
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114.
Groundwater flow and solute transport through fractured rock is highly responsive to the hydraulic anisotropy and heterogeneity that are specific to every major fracture. A major fracture is modeled as the combination of some primal master fractures and several splay fractures that branch out from primal master fractures: step structures (or jog parts). Step structures are commonly observed along a major fracture on various scales. Master fractures were formed and developed by shear movement while some splay fractures were formed by extension normal to their wall. This difference in fracturing process may lead to a permeability difference between master fractures and splay fractures which seems to be one of the major factors controlling flow and solute transport through the fracture networks due to its hydraulic anisotropic and heterogeneous features. This study is composed of two major components: (1) identification and characterization of a step structure from borehole data; (2) evaluation of effect of some idealized step structures on breakthrough curve by numerical simulations. The fracture data of four 1000-m boreholes were used to make clear fracture patterns in the Tono area of Japan. Some major fractures were identified using stereographic projection technique. On the basis of these results, several idealized models of a major fracture having a step was constructed for the numerical study. The obtained results from numerical simulations clearly imply that geometry of step structure plays an important role in flow and transport through the fracture networks. 相似文献
115.
Satoko Niimi Michio X. Watanabe Eun-Young Kim Hisato Iwata Genta Yasunaga Yoshihiro Fujise Shinsuke Tanabe 《Marine pollution bulletin》2005,51(8-12):784
This study presents full-length cDNA sequences of CYP1A1 and 1A2, in common minke whale (Balaenoptera acutorostrata) from the North Pacific. Both CYP1A1 and CYP1A2 cDNAs had an open reading frame of 516 amino acid residues, and predicted molecular masses were 58.3 kDa and 58.1 kDa, respectively. The deduced full-length amino acid sequence of CYP1A1 revealed higher identities with those of sheep (86%) and pig (87%), and that of CYP1A2 was most closely related to human (82%) and monkey CYP1A2 (82%) among species from which CYP1A2 has been isolated so far. Differences in certain conserved and functional amino acid residues of CYP1A1 and 1A2 between common minke whale and other mammalian species indicate the possibility of their specific metabolic function. Concentrations of organochlorine compounds (OCs) including PCBs and DDTs analyzed in common minke whale liver showed no significant correlation with hepatic mRNA expression levels of CYP1A1 and CYP1A2, indicating no induction of these enzymes by such OCs. 相似文献
116.
117.
Abstract. An object-relational data model is an entry point and integral part of geologic analysis system, in which we can start geologic modeling inside a database. A conceptual data model named the Geoscience (Earth Resources) Data Model 3.0 has been developed based on the conceptual design of NADM-C1.0 and EGDM 812. Such adaptation makes this data model interoperable with data models from other geoscience fields. The focus of current data model is to effectively manage multi datasets related with the study of earth resources and to create relationship among data types.
The conceptual data model for earth resources is successfully implemented physically by integrating a GIS and relational data storage. The direct link between relational database and GIS makes the database contents highly visual and spatially enabling. Database contents are fully georeferenced through different types of georeferencing systems that enables data integration, visualization and analysis of multi geoscience datasets in 2D and 3D environment. A new way of geologic analysis through visualization of virtually all kinds of geoscience datasets is proposed.
The earth resources research and industry can take benefits on this system through better data management and effective geologic visualization that in turn accelerate a better understanding of earth resources. Meanwhile wider geoscience community will benefit from better interaction and data sharing among geoscience fields for accelerating a better understanding of our complex earth. 相似文献
The conceptual data model for earth resources is successfully implemented physically by integrating a GIS and relational data storage. The direct link between relational database and GIS makes the database contents highly visual and spatially enabling. Database contents are fully georeferenced through different types of georeferencing systems that enables data integration, visualization and analysis of multi geoscience datasets in 2D and 3D environment. A new way of geologic analysis through visualization of virtually all kinds of geoscience datasets is proposed.
The earth resources research and industry can take benefits on this system through better data management and effective geologic visualization that in turn accelerate a better understanding of earth resources. Meanwhile wider geoscience community will benefit from better interaction and data sharing among geoscience fields for accelerating a better understanding of our complex earth. 相似文献
118.
Yasushi Watanabe 《Mineralium Deposita》2005,40(3):307-323
Kyushu Island, Japan, is located at the junction of the Southwest Japan arc and the Ryukyu arc. There are two major late Cenozoic
epithermal gold-silver provinces in Kyushu, which are termed the Northern and Southern provinces. The provinces are characterized
by: 1) Pliocene volcanism dominated by calc-alkaline andesite, followed by Quaternary volcanism including extrusion of both
calc-alkaline and tholeiitic magmas; 2) formation of extensional grabens; 3) Pliocene to Pleistocene mineralization, which
was dominated by abundant low sulfidation (LS) epithermal deposits with a few high sulfidation (HS) examples. The two epithermal
gold-silver provinces have evolved differently since about 5 Ma; the Northern province has exhibited diminished hydrothermal
activity from the Pliocene to Pleistocene, whereas the Southern province has witnessed increased hydrothermal activity mainly
in easterly and northerly directions. Changes of tectonic setting from the Pliocene to Pleistocene account for the variable
trends in epithermal gold deposit formation. Westward oblique subduction of the Philippine Sea plate beneath the Southwest
Japan arc caused development of the Hohi graben and arc-related volcanism at about 6 Ma. This was associated with widespread
LS mineralization in and surrounding the Hohi graben, as is represented by the Bajo and Taio deposits. The subduction of the
relatively buoyant Kyushu-Palau ridge during the early Pliocene strengthened the coupling between the slab and overriding
Ryukyu arc, leading to polygenetic andesite volcanism with associated HS (Kasuga, Iwato, and Akeshi) and LS (Kushikino) mineral
deposits forming in the Southern province. A change of the subduction direction of the Philippine Sea plate, from west to
north-northwest in the early Pliocene, increased the orthogonal convergence rate between the Southwest Japan arc and the Philippine
Sea plate, resulting in a decrease of volcanic and hydrothermal activity in the Hohi graben of the Northern province. The
more northerly subduction of the Philippine Sea plate shifted the locus of the Kyushu-Palau ridge subduction northward, resulting
in underplating of the older (85–60 Ma), negatively buoyant Amami basin oceanic slab in the Southern province, rather than
continued subduction of the young (27–15 Ma), buoyant Shikoku basin slab. This replacement caused steepening of the slab angle
and slab-rollback in the Southern province, which was associated with regional extension, an eastward shift of the Ryukyu
volcanic front, and development of the Kagoshima and Shimabara grabens, as well as the Okinawa trough. Rhyolite and basalt
volcanism, in addition to andesite volcanism, have occurred since 2 Ma in the area of the Ryukyu back arc; coincident LS mineralization
at Hishikari and Ohkuchi was affiliated with the rhyolite volcanism. Another change of the subduction direction of the Philippine
Sea plate to the northwest occurred at 2–1 Ma. The forearc sliver of the Southwest Japan arc shifted westward, in association
with right-lateral strike-slip faulting along the Median tectonic line, due to the increase of the westward convergence rate.
This shift resulted in shortening and cessation of graben development in the Hohi area, restricting the subsequent volcanism
and related hydrothermal activity to the central part of the graben. 相似文献
119.
Size-separated aerosol number concentrations and water-soluble constituents were measured in Toyama, the Hokuriku district, near the coast of the Japan Sea, during the spring and summer in 2003. The number concentrations of coarse particles were significantly high in April, which was due to Asian dust events called Kosa in Japanese. Particulate nssCa2+, which is mostly present in the coarse-mode particles, was significantly high in April. On the other hand, the concentrations of NH4+ and nssSO42−, which mainly exist as the accumulation-mode particles were not high in April. The mass-size distributions of water-soluble constituents were compared with the size-separated number concentrations of particles. Backward trajectory analysis was also employed to examine the transport process of the air mass in Toyama. 相似文献
120.
Chemical Assessment of Oceanic and Terrestrial Sulfur in the Marine Boundary Layer over the Northern North Pacific during Summer 总被引:2,自引:0,他引:2
K. Aranami S. Watanabe S. Tsunogai A. Ohki K. Miura H. Kojima 《Journal of Atmospheric Chemistry》2002,41(1):49-66
Dimethylsulfide (DMS) in surface seawater and the air, methanesulfonic acid (MSA) and non-sea-salt sulfate (nss-SO4
2–) in aerosol, and radon-222 (Rn-222) were measured in the northern North Pacific, including the Bering Sea, during summer (13 July – 6 September 1997). The mean atmospheric DMS concentrations in the eastern region (21.0 ± 5.8 nmole/m3 (mean ± S.D.), n=30) and Bering Sea (19.9 ± 9.8 nmole/m3, n=10) were higher than that in the western region (11.1 ± 6.4 nmole/m3, n=31) (p<0.05), although these regions did not significantly differ in the mean DMS concentration in surface seawater. Mean sea-to-air DMS flux in the eastern region (21.0 ± 10.4 mole/m2/day, n=19) was larger than those in the western region (11.3 ± 16.9 mole /m2/day, n=22) and Bering Sea (11.2 ± 7.8 mole/m2/day, n=7) (p<0.05). This suggests that the longitudinal difference in atmospheric DMS was produced by that in DMS flux owing to wind speed, while the possible causes of the higher DMS concentrations in the Bering Sea include (1) later DMS oxidation rates, (2) lower heights of the marine boundary layer, and (3) more inactive convection. The mean MSA concentrations in the eastern region (1.18 ± 0.84 nmole/m3, n=35) and Bering Sea (1.17 ± 0.87 nmole/m3, n=13) were higher than that in the western region (0.49 ± 0.25 nmole/m3, n=28) (p < 0.05). Thus the distribution of MSA was similar to that of DMS, while the nss-SO4
2– concentrations were higher near the continent. This suggests that nss-SO4
2– concentrations were regionally influenced by anthropogenic sulfur input, because the distribution of nss-SO4
2– was similar to that of Rn-222 used as a tracer of continental air masses. 相似文献