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We report here that some of the pelitic rocks from the Wanni and Highland Complexes of Sri Lanka reacted with CO2-rich fluids to produce a wide range of unusual secondary carbonate-silicate-oxide-sulphide assemblages. These enable the
depth, temperature and fluid compositions of CO2 reactions to be calculated more rigorously than is generally possible for the patches of arrested charnockite that have been
described from Sri Lanka. Magnesite-andalusite-quartz has partially replaced primary cordierite, and siderite-rutile replaced
ilmenite. Paragenetic sequences involving primary pyrrhotite, ilmenite and magnetite and secondary pyrite-siderite-rutile-magnetite-(hematite)
demonstrate the control which carbonate equilibria have upon evolving fluid compositions during cooling. Direct evidence for
the role of graphite as a source of CO2 is found in the Highland Complex where primary graphite partially reacted with silicates to form secondary siderite assemblages.
It is proposed that following peak metamorphism, continued uplift along a clockwise P-T-t path was accompanied by a series of devolatilization reactions involving breakdown of graphite and the continuous production
of secondary CO2-rich fluids. The limited extent of disseminated secondary carbonate reflects the small amount of graphite inferred to have
been present in the source rocks. These rocks demonstrate that CO2-rich fluids, as found in disseminated fluid inclusions, need not form during peak granulite metamorphism but may be an inevitable
consequence of continued uplift along a clockwise P-T-t path. The arrested charnockite which overprinted some of the hornblende-bearing felsic-intermediate composition rocks in
Sri Lanka most likely formed by the same process.
Received: 4 May 1994 / Accepted: 25 October 1996 相似文献
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Kyuichi Kanagawa Hirobumi Shimano Yoshikuni Hiroi 《Journal of Structural Geology》2008,30(9):1150-1166
The mylonitization of the Pankenushi gabbro in the Hidaka metamorphic belt of central Hokkaido, Japan, occurred along its western margin at ≈600 MPa and 660–700 °C through dynamic recrystallization of plagioclase and a retrograde reaction from granulite facies to amphibolite facies (orthopyroxene + clinopyroxene + plagioclase + H2O = hornblende + quartz). The reaction produced a fine-grained (≤100 μm) polymineralic aggregate composed of orthopyroxene, clinopyroxene, quartz, hornblende, biotite and ilmenite, into which strain is localized. The dynamic recrystallization of plagioclase occurred by grain boundary migration, and produced a monomineralic aggregate of grains whose crystallographic orientations are mostly unrelated to those of porphyroclasts. The monomineralic plagioclase aggregates and the fine-grained polymineralic aggregates are interlayered and define the mylonitic foliation, while the latter is also mixed into the former by grain boundary sliding to form a rather homogeneous polymineralic matrix in ultramylonites. However in both mylonite and ultramylonite, plagioclase aggregates form a stress-supporting framework, and therefore controlled the rock rheology. Crystal plastic deformation of pyroxenes and plagioclase with dominant (100)[001] and (001)1/2 slip systems, respectively, produced distinct shape- and crystallographic-preferred orientations of pyroxene porphyroclasts and dynamically recrystallized plagioclase grains in both mylonite and ultramylonite. Euhedral to subhedral growth of hornblende in pyroxene porphyroclast tails during the reaction and its subsequent rigid rotation in the fine-grained polymineralic aggregate or matrix produced clear shape- and crystallographic-preferred orientations of hornblende grains in both mylonite and ultramylonite. In contrast, the dominant grain boundary sliding of pyroxene and quartz grains in the fine-grained polymineralic aggregate of the mylonite resulted in their very weak shape- and crystallographic-preferred orientations. In the fine-grained polymineralic matrix of the ultramylonite, however, pyroxene and quartz grains became scattered and isolated in the plagioclase aggregate so that they were crystal-plastically deformed leading to stronger shape- and crystallographic-preferred orientations than those seen in the mylonite. 相似文献
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Tsuyoshi Yoshioka Michinobu Furukawa Koji Yoshizaki Ryuji Matsuhashi Yoshikuni Yoshida 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(5):677-683
Recently, energy service providers (ESP) have increased due to deregulation in the power market. They install energy supply
equipment at their own cost and supply the necessary energy to the client. The Tokyo Metropolitan Government started Asia’s
first cap-and-trade program in April 2010. This program caps energy-related carbon dioxide emissions from some 1,330 offices
and factories in Tokyo. Then, ESPs have to manage the many risks of energy service project directly linked to the profits.
In this paper, we describes the risk analysis and investment optimization for energy service projects using financial engineering. 相似文献
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Indialite (hexagonal cordierite) has been found in a cordierite vein of polymetamorphosed pelitic rock, a member of the Unazuki
schists in Hida terrane, central Japan. Most of the indialite grains show intergrowth textures with cordierite of orthorhombic
symmetry. This is the second identification of indialite since the first one from a fused sediment in India.
The intergrowth texture was formed by a nucleation-growth process accompanied with the first order transition from the hexagonal
to the orthorhombic form. Characteristic pseudo-twin relation exists among the orthorhombic phases. Chemical compositions
of both hexagonal and orthorhombic forms in the intergrowth have been deter-mined by analytical electron microscopy. The difference
in Fe/(Mg+Fe) at the interfaces between the two forms indicates the existence of a transition loop in the (Mg, Fe)-cordierite.
The transition of the present specimens is estimated to have initiated at about 700° C. A possible phase diagram of (Mg, Fe)-cordierite
has been proposed, based on the result of this investigation. 相似文献
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Yoshikuni Hiroi 《Tectonophysics》1981,76(3-4)
Petrological and structural characteristics of the regional metamorphic rocks in south-west Japan and in the Korean Peninsula make it possible to speculate on the geological correlation between Japan and the Asian continent prior to the opening of the Sea of Japan, a typical marginal sea. The Hida metamorphic complex, situated on the Sea of Japan side of southwest Japan, is subdivided into two distinct geological units, the Hida gneisses and the Unazuki schists. The Hida gneisses are polymetamorphosed Precambrian rocks, while the Unazuki schists occurring on its eastern and southern sides are low- to medium-grade metamorphic rocks originating from Upper Paleozoic deposits. Sedimentary facies and other geological features suggest that the Hida gneisses were the basemen of the Unazuki schists. Consequently, the geotectonic framework of southwest Japan is revised from north to south as follows: Hida gneiss region (Precambrian massif) Unazuki zone (late Permian intermed.
metamorphic belt) Circum-Hida tectonic zone (Mid- to Late Paleozoic melange zone) Mino-Tanba terrain (Late Paleozoic to Mesozoic geosynclinal region) and so on.The Unazuki zone is similar to the Okcheon zone in the Korean Peninsula in respect of age, lithology and biofacies of sedimentary rocks as well as the age and type of regional metamorphism. Furthermore, the Hida gneisses and the Gyeonggi polymetamorphosed Precambrian gneisses in the Korean Peninsula are similar in the apparent baric type of metamorphism, radiometric ages and the relationship with the overlying metamorphosed formations. The similarity of the geotectonic frameworks of southwest Japan and the Korean Peninsula suggests that the Unazuki zone and the Okcheon zone once formed a continuous geotectonic unit. Thus we have a new geological coordinate in reconstructing the paleogeography prior to the opening of the Sea of Japan. 相似文献
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Microbial community structure analysis of euxinic sediments using phospholipid fatty acid biomarkers
Narasimmalu Rajendran Osamu Matsuda Norifumi Imamura Yoshikuni Urushigawa 《Journal of Oceanography》1995,51(1):21-38
Microbial community structure in sediments, as determined by the phospholipid ester-linked fatty acid (PLFA) analysis, collected from Kojima Lake during summer and winter was described with reference to the environmental quality of the lake. A characteristic feature of the study area was the persistence of anoxia in summer and winter in the deeper area, and the sediments were under the reduced condition with high levels of sulfide, chemical oxygen demand, and low values of oxidation-reduction potential. PLFA profiles of the sediment were dominated by the saturated, branched and monounsaturated fatty acids. Small amounts (less than 5% of the total PLFA) of polyunsaturated fatty acids (biomarker fatty acids of microeukaryotes) and long chain fatty acids were detected in sediments. Total PLFA concentrations in sediments were higher in summer than in winter. Microbial community structure in the lake sediments was predominated by the prokaryotes, as evidenced from the larger amounts of bacterial biomarker fatty acids in the range of C10 to C20. The presence of signature fatty acids of sulfate reducing bacteria in sediments was consistent with the high levels of sulfide in the sediment and anoxic condition in the study area. PLFA showed significant differences in PLFA profiles between shallow and deeper areas, indicating the differences in the lipid contributing communities. However, no such a significant difference was observed between summer and winter. 相似文献
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Yoshikuni Hodoki Kako Ohbayashi Norio Tanaka Hidenobu Kunii 《Estuaries and Coasts》2013,36(1):127-134
This study examined the genetic diversity and composition of 15 populations of Zostera japonica in the Hii River system, Japan. Genetic and genotypic diversity were consistently higher in populations in the Ohashi River than those in Lake Nakaumi, and the local tidal movements may explain the observed patterns of genetic diversity. Pairwise fixation index values among the populations in Lake Nakaumi were higher than among those in the Ohashi River, even though the ranges of the distances among the populations in the two locations were almost the same. The gene flow from the Ohashi River populations was important for some populations in Lake Nakaumi. The low genotypic diversity and gene flow in Lake Nakaumi seemed similar to those of marginal populations. If this low genotypic diversity and genetic differentiation were partly caused by human activities, the promotion of gene flow should be taken into account in conserving the populations in Lake Nakaumi. 相似文献
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