著者

海野 進

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.48, no.2, pp.63-75, 2019 (Released:2019-06-05)

参考文献数

70

被引用文献数

1

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Boninite is the only igneous rock in the IUGS recommendations, which was named after a Japanese island ‘Bonin’, a corrupted Japanese of ‘Munin-to’. Homogeneous glass inclusions in chrome spinel of boninite from Ogasawara, Guam and Oman Ophiolite preserve at least three primary magmas followed by discrete fractionation paths designated high-silica, low-silica, and ultralow-silica boninites, in decreasing degree of source mantle depletion. The T-P conditions and the source depletion of boninites led to a model of subduction initiation along the Izu-Bonin-Mariana (IBM) arc at 52 Ma. The Philippine Sea and Pacific plate boundary was underlain by heterogeneous mantle with depleted harzburgite blocks embedded in depleted mid-ocean ridge basalt (MORB) mantle (DMM). Subsidence of the old and dense Pacific Plate caused upwelling of the heterogeneous mantle, causing adiabatic melting of DMM to MORB, while the refractory harzburgite was uplifted without melting. Fluids from the subducted slab induced flux melting of the MORB residue and harzburgite to generate low- and ultralow-silica boninites and high-silica boninite, respectively. The variations of magma geochemistry in the IBM arc indicate sustained subarc mantle convection, arc magmatism and backarc spreading, which were driven by trench retreat resulted from the foundering dense Pacific Plate. The Oman Ophiolite formed at a divergent plate boundary in the Neotethys and subsequently experienced arc tholeiite and low-silica boninite magmatism, indicating depletion of the source mantle through time. The arc magmatism was caused by thrusting of a rotating microplate over young and buoyant lithosphere, imposing a compressive stress field on the overriding plate. This prohibited forearc spreading and mantle wedge convection, leading to rapid cooling and termination of the arc magmatism in <3 Myr. Os isotopic modeling demonstrate that the enigmatic harzburgite for the IBM high-silica boninite source fractionated from the primitive upper mantle at 1.5-1.7 Ga, whereas the IBM (ultra) low-silica boninite source fractionated at 3.6-3.1 Ga. The average DMM and the source of Oman low-silica boninite differentiated at 2.6-2.0 Ga.

著者

森下 知晃 荒井 章司 田村 明弘 石田 義人

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.37, no.1, pp.1-14, 2008 (Released:2008-05-12)

参考文献数

92

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A peculiar amphibolite rich in deep vivid green-colored amphibole porphyroblast was found as a boulder in the Chiroro River of Hidaka Town, Hokkaido, Japan. The amphibolite mainly consists of deep vivid green-colored amphibole (porphyroblast), colorless amphibole (matrix) and plagioclase with a small amount of chlorite, epidote and chromian spinel. Deep vivid green-colored amphibole porphyroblast is more than 20 modal % in the rock. Chromian spinel rarely occurs as inclusions in deep vivid green-colored amphibole porphyroblast. The Cr2O3 content of the deep vivid green-colored domain is usually ∼1 wt% (up to 2.5 wt% nearby chromian spinel) whereas that of colorless amphibole in the matrix is low, < 0.1 wt%. Deep vivid green-colored amphibole porphyroblast is heterogeneous in chemical compositions within each grain and is divided into three domains as follows: (1) high-Cr2O3 (∼1 wt%, up to 2.5 wt%) and Al2O3 (> 10 wt%) green-colored domain, (2) relatively high-Cr2O3 (∼1 wt%) and low- Al2O3 (< 10 w%) green-colored domain and (3) low-Cr2O3 (< 0.1wt%) and Al2O3 (< 10 wt%) colorless domain. Chondrite-normalized rare earth element (REE) patterns of both deep vivid green-colored amphibole porphyroblast and colorless amphibole in the matrix are characterized by low light REE with positive Eu anomaly. The Cr#[= Cr/(Cr + Al) atomic ratio] and TiO2 content of chromian spinel in the amphibolite are similar to those in a serpentinite complex of the Kamuikotan Zone. The amphibolite was formed by either amphibolitization of a rock containing chromian spinel derived from the surrounding serpentinite complex or extensively metasomatized serpentinite due to interaction with surrounding metamorphic rocks.

著者

龍 徹 木股 三善 西田 憲正 興野 純 清水 雅浩

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.34, no.5, pp.242-251, 2005 (Released:2005-10-18)

参考文献数

27

被引用文献数

2 2

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Chemical evolution of ferrocolumbites from the Ishikawa-yama granitic pegmatites, Fukushima, Japan, has been revealed by electron microprobe analysis. The compositions of ferrocolumbites are different among sample locations, which are within about 1 km distant from each other. Three discernible trends in compositional variations in ferrocolumbites have been observed: (1) a homogeneous crystal trend, with low Ta/(Ta + Nb); (2) a trend with oscillatory zoning related to Ta and Nb; (3) a trend with patchy zoning related to Fe and Mn. Oscillatory zoning of ferrocolumbite is intimately related to crystal growth in magmatic process. Ferrocolumbite with patchy zoning shows parallel extinction and doesn’t appear to have the complementary distribution of octahedral cations due to some coupled substitutions on the plots of partition coefficient (each zone/the assumed average) against ionic radius. These facts and the curved boundaries of patchy zoning suggest that patchy zoning of ferrocolumbite has been produced by topotaxy in the open system.

著者

大谷 栄治

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.20, no.4, pp.209-216, 1991-10-31 (Released:2009-08-11)

参考文献数

29

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The phase transitions in the peridotite composition can account for the observed density and seismic wave velocity profiles of the upper mantle and the transiton zone. On the other hand, the lower mantle is not well constrained by the present experimental data, because of large uncertainties in the physical properties of the lower mantle minerals, and the temperature distribution in the lower mantle. Both a homogeneous mantle with a peridotite composition, and a stratified mantle with a peridotite upper mantle and a silica rich lower mantle can be consistent with the observed seismic data. The source upper mantle of the Al-depleted komatiite observed in the late Archean (2.5 Ga old) shows chondritic abundances of some key refractory lithophile elements compatible with the ultrahigh pressure minerals such as majorite and Mg-perovskite. The Al-depleted and Al-enriched komatiites generally observed in the early Archean (3.5-3.8 Ga old) show evidence of the majorite fractionation, melting at the depths of the transition zone. Recent Hf isotopic data of Al-depleted komatiites imply that the source mantle of the komatiites shows no evience of chemical layering in the early Archean; the source mantle of such komatiites was chondritic in terms of some refractory lithophile elements, such as Al, Ti, Sc, Hf, HREE. Solid state convection might have homogenized the stratification formed by global melting during the accretional stage of the Earth.

著者

南 英一

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.2, no.1, pp.1-24, 1954-09-30 (Released:2009-08-11)

参考文献数

19

被引用文献数

1

著者

相澤 正隆 岡村 聡 新城 竜一 高橋 俊郎 米山団体研究グループ

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.48, no.1, pp.1-24, 2019

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<p>Late Pliocene-Early Pleistocene igneous rocks of Yoneyama Formation from the northern Fossa Magna region, central Japan, consist of basaltic to andesitic rocks and small intrusive rocks; they contain frequently hornblende (Hbl) gabbroic xenoliths and Hbl xenocrysts. Based on field data, together with petrographic, geochemical, and geochlonological descriptions, the volcanism comprised 5 stages. The rocks at the Ogamidake, the 1st and 3rd stages are tholeiitic rock series (TH), whereas calc-alkalic rock series (CA) are dominated at the 2nd and 4th stages. All rocks are characterized by high-K content and contain pargasitic Hbl phenocrysts in both rock series. Estimation using Ca-amphibole geobarometer suggests that Hbls have crystallized at depths of lower crust. Existence of Hbl and high An content of plagioclase (~ An₉₀) in both rock series imply that both magmas are rich in H₂O. Estimated H₂O contents are ~ 5 wt% for both TH and CA magmas. Based on mineral texture, <i>P-T</i> estimation and major-trace elements modeling, we infer that cryptic fractionation of Hbl can produce the TH magma trend. Our model is incompatible with general model that TH magma originate from anhydrous or low H₂O content magma.</p>

著者

和田 浩爾

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.15, no.3, pp.143-150, 1981-11-30 (Released:2009-08-11)

参考文献数

30

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This is a review of color of pearls. It is evident on the base of studies that the color of pearls is the sum of iridescence and body color. The iridescence occurs by the interference of light reflected from the superficial and internal laminar structure of nacre, which is made of the accumulation of crystal layer and thinner organic sheet parallel to the surface of pearls. The crystal layer is from 0.3 to 0.8 μm thick and consists of a definite aggregate of many small tabular crystals of aragonite in a row. On the other hand, the body color is due to the absorption of light by pigment, nacreous matter and other matters.

著者

阿部 なつ江 荒井 章司

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.34, no.4, pp.143-158, 2005 (Released:2005-09-10)

参考文献数

89

被引用文献数

6 12

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Recent developments in instrumentation for in situ trace element analysis of peridotite minerals give us valuable data set of petrological and geochemical insights of the upper mantle. Here, we summarize petrographical, petrological and geochemical characteristics of mantle xenoliths from the Northeastern and Southwestern Japan arcs. They have clear correlations between microtexture and mineral compositions in terms of both major and trace elements. That suggests that influx-assisted melt extraction occurs simultaneously with deformation/recrystalization in the upper mantle. Their characteristics of trace-elements in clinopyroxene are distinguished from those of abyssal peridotite and peridotite xenoliths from continental regions. The geochemistry of Japan arcs’ clinopyroxenes have characteristics of arc-type mantle source; i.e., low light rare earth element (LREE) and high field strength element (HFSE; Ti, Zr and so on), rather high heavy rare earth (HREE) relative to LREE elements and Sr concentrations. They also have a rather constant Ti/Zr ratio, variable REE patterns, and relatively low LREE/HREE ratios. The simple melt extraction model can not explain these characteristics. These features are due to metasomatism, which is different from carbonatite metasomatism.

著者

ABBOU-KEBIR Khadidja ARAI Shoji HASSAN AHMED Ahmed CEULENEER Georges

出版者

一般社団法人 日本鉱物科学会

雑誌

Journal of mineralogical and petrological sciences (ISSN:13456296)

巻号頁・発行日

vol.106, no.5, pp.235-245, 2011-10-01

参考文献数

45

被引用文献数

3

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Enigmatic dunitic veins and veinlets crosscutting a podiform chromitite ore body discovered in Wadi Rajmi, northern Oman ophiolite, display a peculiar characteristic of being almost or completely spinel-free. Olivines show an evolution trend from the spinel-free dunites (Fo_93-94 and 0.4 wt% NiO) to the spinel-bearing dunites (Fo_91-93 and 0.2-0.3 wt% NiO). The Cr/(Cr + Al) of chromian spinel grains increases from 0.6 to 0.8, accompanied by a slight increase in Fe³⁺ ratio, and the Fo content of olivine decreases in the spinel-bearing dunites. A high-Mg magma, initially undersaturated with chromian spinel, precipitated the spinel-free dunites. Once the spinel saturation of the melt was attained by fractionation, the spinel-bearing dunites precipitated. The initial magma was possibly komatiitic in nature, which was produced at an early stage of detachment of the oceanic lithosphere that formed the Oman ophiolite.

著者

皆川 鉄雄

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.42, no.1, pp.30-33, 2013 (Released:2013-03-02)

参考文献数

20

著者

張 永杰 吉村 尚久

出版者

一般社団法人 日本鉱物科学会

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.92, no.9, pp.363-378, 1997 (Released:2006-09-22)

参考文献数

33

被引用文献数

1 1

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南部丹沢山地に分布する安山岩質—玄武岩質火山岩類からなる中新世丹沢層群は,束沸石,濁沸石,ブドウ石—パンペリー石,緑れん石,緑れん石—角閃石及び角閃石帯に分けられる。これらの帯に産出するブドウ石,パンペリー石及び緑れん石のFe3+/(Fe3++Al)値は変成温度の上昇に伴い低くなり,一つのサンプルあるいは変成帯でも産状と共存鉱物によって,異なっている。グランダイトザクロ石が同定され,また,その形成条件が検討された。ブドウ石,パンペリー石及び緑れん石が高いFe3+値を示すことと赤鉄鉱+スフェンが広く出現することによって,変成時の高いfo2が推定される。高いFe3+値のブドウ石,パンペリー石及び緑れん石の安定条件はfo2に強く支配されることから,ブドウ石—パンペリー石帯から角閃石が出現しない緑れん石帯への転換が解釈できる。

著者

広渡 文利 福岡 正人

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.18, no.6, pp.347-365, 1989-01-25 (Released:2009-08-11)

参考文献数

38

被引用文献数

1 3

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This paper described the following three topics concerning with the studies on the manganese minerals in Japan from the mineralogical viewpoint.1). Historical developement and mineral species of the Japanese manganese minerals. The number of the manganese mineral species confirmed to occur in Japan during from 1887 to 1987 amount to 88 (silicates 44, oxides 30, sulfates 5, borates 3, carbonates 2, sulfides 2, tungustate 1, and arsenate 1). Mineral name, chemical composition, localities, and authors of the manganese minerals found first in Japan are listed as a table in chronological order.2). Manganoan sugilite and associated other minerals from the Furumiya mine. The mode of occurrence, microscopic feature, chemical composition, and X-ray powder diffraction data for the manganoan sugilite are described. The mineral occurs as veinlets of purple tint with guartz vein cutting braunite ore, and it is found associated with serandite, sanbornite, krauskopfite, and Mn-alkali amphibole. These associated minerals are determined by means of EPMA.3). Witherite and “BaMn (CO3)2” mineral (unnamed new mineral) from the Hagidairaand Fukumaki mines. Both the minerals from the Hagidaira mine are found in rhodochrosite-manganositea-labandite ore. The witherite occurs as a fine-grained aggregate, while the “BaMn (CO3)2 ” mineral is coarse-grained crystal, and it is surrounded by the fine-grained witherite. The mode of occurrence, optical properties, chemical composition, and X-ray powder diffraction data for the witherite and “BaMn (CO3)2” mineral from the Hagidaira mine are described. On the other hand, the witherite and “BaMn (CO3)2 ” mineral from the Fukumaki mine occur in manganosite-tephroite-galaxite ore. The mode of occurrence, optical properties, and chemical composition of both the minerals are generally similar to those of the Hagidaira mine. However, although individual crystals of both the minerals from the Fukumaki mine are much too small, the X-ray powder diffraction data of them are not determined yet.

著者

森 慎一 山下 浩之 有馬 眞 藤岡 換太郎

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.41, no.3, pp.67-86, 2012 (Released:2012-06-28)

参考文献数

185

被引用文献数

2 3

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We determined K-Ar ages of the late Miocene to Pliocene andesitic to basaltic dykes and lavas distributed in the Tanzawa-Oiso area in the southern Fossa Magna region, central Japan. Our data indicate two distinct periods of volcanic activity in this region; one took place during the middle Miocene (about 15 Ma) and another during the late Miocene to Pliocene (7.5-4.2 Ma). Combined the present results with the age data reported previously from volcanic rocks in the southern Fossa Magna region, the present study suggests that the volcanic front in this region during 8 to 4 Ma was located at about 40 km east of the present-day volcanic front. The volcanic front began to migrate westward to the present-day location at about 4 Ma. The westward migration of volcanic front was probably associated with an abrupt change of lateral motion of the Philippine Sea Plate from north- northwestward to northwestward occurred between 4 and 2 Ma.

著者

諏訪 兼位

出版者

一般社団法人 日本鉱物科学会

雑誌

鉱物学雜誌 (ISSN:04541146)

巻号頁・発行日

vol.19, no.5, pp.265-272, 1990-08-31 (Released:2009-08-11)

参考文献数

21

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This is to review some phases in the history of petrography and petrology. Petrology has developed on a deep understanding that a rock is not a rock-fragment in any sample case but an important constituent of the earth and planets. Some recent works on some rock-forming minerals done in my laboratory are introduced in this paper. Some random thoughts on amalgamators of mineralogy and petrology are presented. Mineralogy has developed recently as mineralogical science. It has two main aspects: (a) earth and planetary science, and (b) material science. Mineralogical science as material science should consider the earth and planets to develop further.

著者

木村 純一

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

pp.120611b, (Released:2013-01-12)

被引用文献数

1 2

著者

飯塚 義之

出版者

一般社団法人 日本鉱物科学会

雑誌

岩鉱 (ISSN:09149783)

巻号頁・発行日

vol.91, no.3, pp.73-85, 1996 (Released:2006-12-13)

参考文献数

22

被引用文献数

2 1

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Komochi volcano (1,296 m), located at the southernmost part of NE Japan arc, is a Quaternary composite volcano with a diameter of approximately 6 km and a volume of approximately 10 km3. The basement is composed of the Kirigakubo Formation, a member of the Miocene rhyolitic tuff formation, and Iwamoto volcanoes, dacite lava domes (ca. 6 Ma). The rocks of the Komochi volcano consist of low-K andesites with small amounts of basaltic andesite and dacite. All rocks of the Komochi volcano belong to the hyperthenic rock series. The volcanic activity of the Komochi volcano can be divided into following three stages: Ayado stage (c.a. 1.6 Ma), Early Komochi (0.9 Ma-) and Late Komochi (0.6-0.2 Ma) volcano stages which is subdivided into the two kinds of activities: stratovolcano-forming and lava dome-forming. At any stage, a large number of andesitic dikes intruded, which comprise radial dike swarm in the circumference of the Daikokuiwa neck. The Komochi volcano has a life span of about 1.4 m.y. and calculated production rate of 0.14-0.25 km3/104 yr., which is very small compared to lager volcanoes around Komochi volcano, for example Myoko and Hakone volcanoes, and even smaller than similar volcanoes in the Shin-etsu Highland area.

著者

岡本 敦

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.41, no.5, pp.185-192, 2012 (Released:2012-11-30)

参考文献数

33

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Serpentinization is a hydration process that causes significant changes in physical and chemical properties of the oceanic lithosphere. Based on hydrothermal experiments, the reaction rates of serpentinization have been empirically obtained for typical reaction (i.e., Olivine+H2O → Serpentine+Brucite) as a function of temperature and initial grain size of the reactant mineral. However, the rate equations used for these analyses take quite empirical forms, in which the solution chemistry (saturation state) is not taken into consideration; therefore, it is difficult to extrapolate the results to different conditions and to predict evolution of the fluid chemistry in the hydrothermal systems. Serpentinization reactions are characterized by coupled dissolution of primary minerals (Olivine, Pyroxenes) and formation of secondary minerals (Serpentine, Brucite, Talc, Magnetite); therefore, the rates of elementary reactions between individual minerals and solution will be required for estimating the rate of overall hydration reaction. I also discuss the effects of competitive processes among grain surface reactions, element diffusion, water supply and structural development during serpentinization.

著者

松山 文彦 藤本 雅太郎 松原 聰

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.35, no.4, pp.207-211, 2006 (Released:2006-08-30)

参考文献数

18

被引用文献数

1

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Garronite occurs as radiating aggregates of minute fibrous crystals in amygdales of altered trachybasalt from Kuniga, Oki Islands, Shimane Prefecture, Japan. The mean chemical composition by EDS analysis leads to the empirical formula, (Na1.15K0.15)Σ1.30Ca2.28 [Al5.88Si10.06]O32·13.60H2O on the basis of O=32 in anhydrous part and H2O by difference. The unit cell parameters calculated from the X-ray powder diffraction data are a = 9.961 (3), b = 10.178 (4), c = 9.958 (4) (Å) and β = 90.020 (1) (°) with a monoclinic cell.

著者

Zaw Win Ko 榎並 正樹 青矢 睦月

出版者

一般社団法人 日本鉱物科学会

雑誌

日本岩石鉱物鉱床学会 学術講演会 講演要旨集 2003年度 日本岩石鉱物鉱床学会 学術講演会

巻号頁・発行日

pp.34, 2003 (Released:2004-12-31)

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四国三波川帯・別子地域の瀬場谷中流域は、曹長石-黒雲母帯に属し、変斑れい岩 (250 m × 150 m)を取り巻いて、少量の泥質片岩を伴う塩基性片岩が不定形のレンズ状 (2 km × 1 km) に分布している。これらの岩相からは、散在的にではあるがエクロジャイト相の鉱物組み合わせが報告されており、変斑れい岩と塩基性片岩を主とするレンズ全体はエクロジャイト・ナップの一部をなし、エクロジャイト相の変成作用を経験していないとされる通常の結晶片岩類の上位に重なると考えられている。しかしながら、このエクロジャイト・ナップに属するとされる泥質片岩からは、エクロジャイト相での平衡を示す岩石学的・鉱物学的デ-タは報告されていない。そこで、泥質片岩中からエクロジャイト相変成作用の情報を読みとることを目的として、クロリトイドを含む泥質片岩に注目して研究を行った。その結果、新たにクロリトイド+バロワ閃石の共生を見いだした。今回はこの共生が、エクロジャイト相条件下で安定であったことを論じる。 検討した2試料において、クロリトイドと黒雲母が、ざくろ石の包有物としてのみ産する。そのほかの鉱物としては、ざくろ石、バロワ閃石、パラゴナイト、フェンジャイト、緑泥石、緑レン石、石英、電気石、チタナイトおよびルチルが認められ、パラゴナイト以降の鉱物は、ざくろ石の包有物としても産する。曹長石は、ざくろ石の包有物としては認められないが、基質部にバロワ閃石や緑泥石をともなう細粒集合体として、きわめてまれに産することがある。クロリトイド:mg# [= Mg/(Mg+Fe)]値は0.29-0.33であり、中・低圧変成岩中のもの(mg# ざくろ石:結晶の中心部から周辺部にかけて、MgとFeが増加し、Mn およびCa が減少する昇温型累帯構造を示し(Alm49-66Prp8-18Grs14-24Sps2-23)、曹長石-黒雲母帯に属するクロリトイドを含まない泥質片岩中のざくろ石 (Alm25-73Prp1-12Grs13-39Sps0-50) に比べて、Mgに富む。バロワ閃石:Al (1.65-2.34 pfu) とNa (0.95-1.57 pfu) に関して広い組成範囲を有し、曹長石-黒雲母帯に属する他の泥質片岩中の角閃石 (Na 緑泥石:基質の緑泥石は均質(Si = 2.7-2.8 pfu, mg# = 0.60-0.64)である。一方、包有物として産する緑泥石は、Si量が3 pfuを超えて広い組成範囲を示し (Si = 2.7-3.3 pfu, mg# = 0.50-0.73)、それは緑泥石とタルクがサブミクロン単位で互層していることによると解釈される。 Holland & Powell (1998)の熱力学データベースを用いて見積もった、クロリトイド+緑泥石+バロワ閃石+ざくろ石+パラゴナイト+石英の組成共生の平衡条件は、540-570 C・1.6 GPaである。一方、緑泥石+クロリトイド+ (タルク) の共生から得られる圧力条件は、550 Cにおいて1.8-1.9 GPaである。これらの平衡条件は、エクロジャイト・ナップの下位に位置するとされている周囲の結晶片岩類 (500-580 C・0.8-1.1 GPa) に比べると、有意に高圧条件を示し、変斑れい岩および塩基性片岩中のエクロジャイト共生の平衡条件 (610-640 C・1.2-2.4GPa) とは矛盾しない。今回の研究結果は、泥質片岩を含めてレンズ部の結晶片岩類全体が、エクロジャイト相変成作用を経験したことを示しており、エクロジャイト・ナップの存在を強く示唆す

著者

北風 嵐

出版者

一般社団法人 日本鉱物科学会

雑誌

岩石鉱物科学 (ISSN:1345630X)

巻号頁・発行日

vol.39, no.1, pp.32-33, 2010 (Released:2010-03-27)

参考文献数

10