著者

佐藤 比奈子 石山 大三 水田 敏夫 松葉谷 治 村上 史一

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.60, no.1, pp.15-24, 2010 (Released:2013-06-14)

参考文献数

13

被引用文献数

3

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Tamagawa hot spring is a volcanic gas-bearing hydrothermal system derived from Quaternary andesitic to dacitic magma beneath Yakeyama volcano. Thermal waters and precipitates of Tamagawa Hot Spring in 2002 and 2007 were investigated to clarify the geothermal structure of the area. Thermal waters in Tamagawa Hot Spring area are divided into three types: Cl-SO4type (Ohbuki Hot Spring: pH 1.2), SO4type (pH 1.8 to 2.9) and neutral-type (pH 6.1). Concentrations such as F, Cl, SO4, Na, K, Mg and Ca in Cl-SO4type Ohbuki thermal water are ten to several hundred-times higher than those of elements in SO4type thermal waters. The concentrations of elements in SO4 type thermal waters also varied according to changes in geothermal structures supplying steam and the flow system of groundwater and vapor in Tamagawa geothermal system from 2002 to 2007.The oxygen and hydrogen isotopic ratios of the thermal waters in the system suggest that SO4 type thermal waters are formed by heating of shallow groundwater by the steam separated from Ohbuki thermal water below Tamagawa Hot Spring area. On the other hand, the small variation of chemistry and hydrogen and oxygen isotopic ratios of Cl-SO4 type Ohbuki thermal water from 2002 to 2007 suggests that the Cl-SO4 type Ohbuki thermal water originates from a deeper part of Yakeyama Volcano. The flow rate of Cl-SO4 type Ohbuki thermal water below Tamagawa hot spring area was estimated to be 13,000 l/min.

著者

水田 敏夫 小畑 正明 江上 桂子

出版者

特定非営利活動法人 日本火山学会

雑誌

火山.第2集 (ISSN:24330590)

巻号頁・発行日

vol.35, no.2, pp.249-262, 1990-07-02 (Released:2018-01-15)

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Morphology, abundance and vertical distribution of vesicles were studied in a thick (40-60 m) andesitic lava flow, that lies in the underground of Kumamoto City. The vesicles are frozen bubbles that were fomed in the molten lavas at the time of its eruption. The lava can be divided into three zones: (1) an upper vesicular zone (2) a middle non-vesicular and compact zone and (3) a lower, thinner vesicular zone. The vesicles in the upper zone are elongated vertically, probably due to bouyancy-driven ascent of the bubbles, and those in the lower zone are flattened and elongated horizontally, that may be ascribed to a viscous shear flow at the bottom of the lava flow. Size distribution of the vesicles typically display nearly the log-normal distribution. Abundance, the mean size and the number density of the vesicles are greater in the upper zone than in the lower zone. Such vesicle distribution pattern is consistent to the hypothesis that the lava originally contained abundant bubbles when it was poured on the ground and then the bubbles started to ascent in the lava. Vesicles in the lower zone were the bubbles trapped by the advancing cooling front from the bottom surface of the lava. Bubbles that have escaped from the cold trap below have been accumulated in the upper zone and have been frozen in the lava upon cooling from the top surface. Mass balance calculation, however, indicates that much of the bubbles that were originally present in the lava, have been escaped through the lava surface. A dynamic cooling model was, therefore, proposed, that is to say, in the presence of surface flow in the lave during its cooling, impermeable lava crusts may not be maimtained so that gas bubbles may leak out of the lava into the air.

著者

水田 敏夫

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.73, no.7, pp.202-215, 1978-07-05 (Released:2008-08-07)

参考文献数

42

被引用文献数

2 4

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Peridotites characterized by the texture of elongated olivine crystals, are found in the Higo metamorphic belt mainly composed of psammitic gneiss. The peridotite mainly consists of olivine, orthopyroxene, tremolite, serpentine, and talc. Spinifex-like olivine crystals, partly altered to serpentine and magnetite, consist of randomly oriented plates parallel to (010). The elongated olivine crystals in same handspecimen are chemically homogeneous, and the compositional zonation of the crystals has not been observed by microprobe analysis. However, the chemical composition of olivine ranges from FO83 to FO92 in different handspecimens. The NiO content of olivine varies from 0.2 to 0.5 weight per cent and the MnO content from 0.1 to 0.2 weight per cent. The NiO and MnO contents are about the same as those of komatiitic olivines. On the other hand, the olivines in the Higo perioditite contain a negligible amount of CaO and remarkabIly differ from those of extrusive peridotite (komatiite). The rocks are free from clinopyroxene and contain large and prismatic orthopyroxene. The extremely Ca-depleted orthopyroxenes (En89-En92) are interlocked with tabular olivines in each other. The Al2O, and Cr2O3 contents of orthopyroxenes are relatively lower than those of orthopyroxenes in alpine peridotites. From the mineral assemblages of peridotites and metamorphic rocks, and from the chemical composition of olivine and orthopyroxene, it is suggested that the peridotite bodies suffered from the regional metamorphism of amphibolite facies (approximately 700°C, 3-4kb). This conclusion is also supported by the data concerning Mg-Fe2+ distribution between olivine and chromian spinel in the Higo peridotite.

著者

水田 敏夫 小畑 正明 江上 桂子

出版者

特定非営利活動法人日本火山学会

雑誌

火山. 第2集 (ISSN:04534360)

巻号頁・発行日

vol.35, no.2, pp.249-262, 1990-07-02

被引用文献数

3

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Morphology, abundance and vertical distribution of vesicles were studied in a thick (40-60 m) andesitic lava flow, that lies in the underground of Kumamoto City. The vesicles are frozen bubbles that were fomed in the molten lavas at the time of its eruption. The lava can be divided into three zones: (1) an upper vesicular zone (2) a middle non-vesicular and compact zone and (3) a lower, thinner vesicular zone. The vesicles in the upper zone are elongated vertically, probably due to bouyancy-driven ascent of the bubbles, and those in the lower zone are flattened and elongated horizontally, that may be ascribed to a viscous shear flow at the bottom of the lava flow. Size distribution of the vesicles typically display nearly the log-normal distribution. Abundance, the mean size and the number density of the vesicles are greater in the upper zone than in the lower zone. Such vesicle distribution pattern is consistent to the hypothesis that the lava originally contained abundant bubbles when it was poured on the ground and then the bubbles started to ascent in the lava. Vesicles in the lower zone were the bubbles trapped by the advancing cooling front from the bottom surface of the lava. Bubbles that have escaped from the cold trap below have been accumulated in the upper zone and have been frozen in the lava upon cooling from the top surface. Mass balance calculation, however, indicates that much of the bubbles that were originally present in the lava, have been escaped through the lava surface. A dynamic cooling model was, therefore, proposed, that is to say, in the presence of surface flow in the lave during its cooling, impermeable lava crusts may not be maimtained so that gas bubbles may leak out of the lava into the air.

著者

大口 健志 石山 大三 水田 敏夫 林 信太郎 佐藤 比呂志 石川 洋平 佐藤 時幸

出版者

秋田大学

雑誌

一般研究(B)

巻号頁・発行日

1990

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1.脊梁山地,出羽山地,男鹿半島域などに分布する台島-西黒沢期火山-堆積岩相について層位学・火山地質学的研究を行った結果,つぎのことが明らかになった;(1)新庄盆地北端部の模式地に露出する及位層から台島型に属する可能性の高い植物化石が発見され,さらに,秋田県南部の層序との連続からしても及位層の大部分は台島層に対比できること,(2)東北日本内帯における台島-西黒沢期末期の生層位学的対比基準面として扱われ,同時異相と考えられていた須郷田層と大森層は,互いに上(大森層)・下(須郷田層)関係にあり,石灰質ナンノ化石分帯のNN4-5帯に須郷田層が対比されること,(3)秋田一庄内油田域に伏在する西黒沢期玄武岩類は須郷田層の形成期間内に急激に噴出したこと,(4)寒河江川流域の大規模珪長質火山作用は大森層と同様,NN6/5境界以降に出現した陥没域で始まったこと,(5)男鹿半島の台島層(藤岡,1959)は下位から上位へ,帆掛島石英安山岩,館山崎玄武岩,館山崎緑色凝灰岩,台島層主部に4分され.広域火砕岩である帆掛島部層を不整合に被う館山崎玄武岩部層以降を台島層として扱うのが妥当であること。2.背弧海盆拡大期に活動した砂子淵層玄武岩類の層相解析から,多量のマグマ水蒸気爆発起源の火砕物質によって特徴づけられる砂子淵層は,乾陸から半深海性の海進にともなう堆積環境下において,当時の汀線付近で継続的に行われた火山作用によって形成されたものであることが判明した。3.北鹿・黒鉱鉱床形成期前後の玄武岩類と,砂子淵層玄武岩類は共通した岩石化学的性質を示し,back arcbasaltと類似している。黒鉱鉱化溶液の生成には玄武岩類からの金属元素の抽出が寄与したらしい。砂子淵層および新潟平野・七谷層の水冷玄武岩のrim部における発泡度は,由利原油・ガス田のものとくらべて低い。

著者

渡辺 寧 村上 浩康 松枝 大治 吉田 武義 水田 敏夫 石山 大三 清水 正明 木村 純一 渡邊 公一郎 今井 亮 浦辺 徹郎 鹿園 直建 林 謙一郎 実松 健造 星野 美保子

出版者

独立行政法人産業技術総合研究所

雑誌

基盤研究(A)

巻号頁・発行日

2007

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世界各地の重希土類およびインジウム鉱床の調査を実施し,ベトナム,タイ等東南アジア地域で重希土類に富む花崗岩風化殻を発見するとともに,日本,中国,ベトナム,ペルー, ボリビアでのインジウムの資源量の見積もりを行った.これらの結果,中国以外の地域でも重希土類およびインジウムの資源ポテンシャルが存在することが判明し,また鉱床成因のための必要条件が考察された.