著者

中村 仁美 岩森 光

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.56, no.4, pp.76-86, 2022-12-25 (Released:2022-12-25)

参考文献数

66

---

Arima-type hot spring waters that exhibit unique geochemical characteristics and their formation are reviewed based on subduction-zone-scale perspectives and studies concerning fluid circulation. Arima-type hot spring waters produced in non-volcanic regions exhibit properties similar to those of volcanic fluids. In order to clarify the formation mechanism, we first review the definition of volcanic/non-volcanic regions and their essential differences. Then we discuss the dehydration reactions in the subducting plates, the resulting distribution and geochemical characteristics of slab fluids, and present evidences of their ascent into the Japanese crust and their role in the global material cycling. In addition, the characteristics and causes of the recently discovered Arima-like hot spring water in the Eurasian continent are reported, and the extent of the material circulation in the wide subduction zone is discussed.

著者

加藤 真悟

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.49, no.1, pp.1-17, 2015-03-25 (Released:2015-03-30)

参考文献数

87

被引用文献数

2

---

Iron is a key element to understand global biogeochemical cycling. Microorganisms are involved in redox cycling of iron in natural environments. In particular, neutrophilic iron-oxidizing microorganisms that grow at circumneutral pH potentially play a significant role in global iron oxidation at redox boundaries. However, little is known about neutrophilic iron-oxidizing microorganisms because only a few cultivated species have been reported to date despite a long research history. In this review, knowledge about neutrophilic iron-oxidizing microorganisms, i.e., phylogeny, physiology, ecology, spatial distribution, and unique extracellular polymeric substances, is summarized, including the most recent reports. This will provide useful information to various scientific fields: not only microbiology, but also geochemistry, astrobiology and environmental engineering.

著者

田畑 亜希子 横尾 頼子 中野 孝教 徳増 実

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2010年度日本地球化学会第57回年会講演要旨集

巻号頁・発行日

pp.124, 2010 (Released:2010-08-30)

---

愛媛県西条市市之川とその支流および加茂川の河川水と河床堆積物の元素組成を調べ,河川水および河床堆積物への市之川鉱山の影響を明らかにした.市之川本流の河床堆積物中のSbやAsの濃度は,市之川鉱山付近よりも下流の地点で高かった.SbやAsを多く含む粒径の細かい砕屑物が市之川鉱山から運ばれて下流で堆積していると考えられる.市之川本流の河川水中のSb,As,Fe,SO4濃度は鉱山より下流の地点でより高くなり,市之川鉱山からの粒径の細かい堆積物に含まれる輝安鉱(Sb2S3)や硫ヒ鉄鉱(FeAsS)の風化や支流の流入が影響している.市之川本流の河床堆積物中の水溶性・交換性イオンの抽出量は粒径の細かい堆積物ほど多く,特にSb,As,SO4の抽出量は市之川鉱山付近よりもさらに下流の地点で多かった.加茂川でのSbとAsの河川水および河床堆積物中の濃度,水溶態・交換態の抽出量は,市之川合流直後よりもさらに下流の地点でより高く,市之川鉱山の影響がみられた.

著者

北台 紀夫

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.53, no.3, pp.91-105, 2019-09-25 (Released:2019-09-25)

参考文献数

116

---

How and where did life on Earth originate? Did the life’s origin happen from a combination of a huge number of geological events that were specially and temporally separated from each other, or did it occur within a local environment through a series of chemical processes that were compatible with the conditions prevailing within the setting? One of the key sites to resolve these questions is deep-sea hydrothermal systems, where the emergence of protometabolism through sulfides-promoted abiotic CO2 fixation has long been suggested to be the most plausible initial process toward the origin of life. However, geochemical mechanisms to harness the reductive power provided by hydrothermal systems remain to be elucidated. Here, this review introduces “geoelectrochemistry” as a general potent means to realize protometabolism at the vent–seawater interface in early ocean hydrothermal systems. Based on the relevant field, laboratory, and theoretical investigations of these systems, together with the latest astronomical observations of extraterrestrial planets/satellites, the fundamental nature of driver for life are discussed as a base to consider the ubiquity and similarity of life in Universe.

著者

盛合 秀 折橋 裕二 佐々木 実 沼田 翔伍 浅沼 尚 平田 岳史 淺原 良浩

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2021年度日本地球化学会第68回年会講演要旨集

巻号頁・発行日

pp.168, 2021 (Released:2021-12-15)

---

本研究では檜川層の模式地である檜川流域およびその周辺域と西岸域(仏ヶ浦を含む福浦〜牛滝・野平の地域)に分布する珪長質火山岩および火砕岩について地質調査を行い,檜川層層序の再検討を行った.また,新たに縫道石山の石英斑岩についてU-Pb年代測定を行った.野平盆地は地形的に二重の盆状構造を呈しており,負の重力異常分布域(広島ほか,1989)からも示唆されることから,約 4 Maに浅海域で形成された「仏ヶ浦カルデラ」(新称)と約 2 Maに陸域で形成された野平カルデラ(根本・箕浦,1999)が重複していると考えられる.今回新たに得られた縫道石山・石英斑岩のジルコンU-Pb年代は4.7 Maであり,これら石英斑岩は仏ヶ浦カルデラ形成前のリング・ダイクと推定される.

著者

永峰 康一郎 茅野 琴乃

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2010年度日本地球化学会第57回年会講演要旨集

巻号頁・発行日

pp.142, 2010 (Released:2010-08-30)

---

「丹」とも呼ばれた硫化水銀の鉱石である辰砂を産する地には「丹生(ニウ)」という地名がつけられているという。水銀鉱床と「丹生」という地名との関連性については、これまで歴史学の分野で研究が行われてきたが、由来がはっきりしない地点も多い。そこで本研究では、地球表層の元素濃度分布を地図に表した地球化学図を用いて両者の関連性の検証を試みた。但し北海道はアイヌ語に由来する地名が多いため対象から除外した。その結果、「丹生」の地名がある地点で、地球化学図からも辰砂の産出が認められる地点とそうでない地点があった。また「丹生」以外の辰砂産出を由来としていると考えられる地名が、高濃度の水銀が検出された地点の周辺にあった。

著者

唐牛 譲 石橋 之宏 上椙 真之 矢田 達 中藤 亜衣子 熊谷 和也 岡田 達明 安部 正真

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.48, no.4, pp.211-220, 2014-12-25 (Released:2015-01-06)

参考文献数

17

被引用文献数

1

---

The Extraterrestrial Sample Curation Center of JAXA curates the Hayabusa-returned samples in conditions of minimum terrestrial contaminants, because these samples are very tiny. We evaluated the cleanliness of the handling instruments, the cleanroom environments and the sample storage chamber to improve the cleanliness of particles, organic molecules and metallic elements to a level not to affect the analyses of the Hayabusa-returned samples. In the environment of the clean chamber No. 2 where the samples have been stored, the organic molecule abundance was lower than the detection limit, furthermore, metallic elemental concentrations were the lowest among other evaluated place. A multi-stage ultrasonic cleaning by organic solvents and the ultrapure water have been applied to instruments made of stainless steel and/or aluminum alloy, and additionally, acid-alkali liquids cleaning have been performed for those made of quartz glasses. For the cleanliness of quartz glasses after the cleaning, the organic molecules abundances were blank level, and the metallic element concentrations were 1~100×109atom/cm2/24 h. It was confirmed by optical microscope that no particle of size more than 10 μm was observed on quartz glasses after the cleaning.

著者

西田 梢

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.56, no.1, pp.1-17, 2022-03-25 (Released:2022-03-25)

参考文献数

96

---

Climate changes, such as global warming and ocean acidification, are projected to affect survival, growth, and metabolic and physiological activities in marine calcifiers. To improve understanding of the future climate and its impact on marine calcifiers, development of environmental and ecological proxies by using culture experimental and isotope geochemical approaches are important. This review undertook recent advances in (1) culture experimental study that has implications for understanding the evolution of biomineralization and future impact on marine calcifiers, and in (2) environmental and ecological proxies by using stable and radio isotopes of biogenic carbonate to enhance understanding of the climate reconstruction and physiological effect under changing environment. The use of cultured specimens under well-controlled environmental conditions for geochemical studies will improve the application of environmental proxies, and will also be applicable for the estimation of carbon assimilation and physiological effect on calcification. In addition, micro-volume stable isotopic analysis will contribute to ensuring the reliability of international standard reference materials of carbonate and to promote high-resolution environmental reconstruction in collaboration with various research fields.

著者

角野 浩史 ウォリス サイモン 纐纈 佑衣 遠藤 俊祐 水上 知行 吉田 健太 小林 真大 平島 崇男 バージェス レイ バレンティン クリス

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集

巻号頁・発行日

vol.64, 2017

---

<p>四国中央部・三波川変成帯に産する変泥質岩、エクロジャイト、蛇紋岩、かんらん岩のハロゲン・希ガス組成は一様に、深海底堆積物中の間隙水と非常によく似た組成を示す。同様の組成は島弧火山岩中のマントルかんらん岩捕獲岩や深海底蛇紋岩でも見られることから、沈み込み前に屈曲したプレートの断層沿いにプレート深部に侵入した間隙水がスラブマントルを蛇紋岩化する際に、ハロゲンと希ガスが組成を保ったまま蛇紋岩に捕獲されて沈み込み、水とともにウェッジマントルへと放出されている過程が示唆される。</p>

著者

吉村 寿紘

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.52, no.3, pp.131-142, 2018-09-25 (Released:2018-09-25)

参考文献数

59

---

Major cations (Na, Mg, K and Ca) are essential for life and play a major role in the global geochemical cycles. Dissolved cations in terrestrial waters derive from both silicate and carbonate rocks, and rivers and groundwater deliver them to the ocean, where there is a steady-state balance between inputs and outputs over geological time. Calcium carbonates are central components in understanding the chemical budgets of major cations for modern and past oceans. Biogenic CaCO3 is an important tool for elucidating the oceanic chemical evolution and past climate changes. Recent advances in mass spectroscopy techniques have made it possible to explore the stable isotope system of Mg, Ca, K and Sr in geologic materials, each of which are novel indicator for constraining the interplay of natural systems in the geological past; continental weathering, carbonate budgets, mid-ocean ridge spreading rates, etc.

著者

増田 彰正

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.37, no.1, pp.31-41, 2003-03-19 (Released:2017-01-12)

被引用文献数

1

著者

菅崎 良貴 村上 隆

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.51, no.2, pp.61-77, 2017-06-25 (Released:2017-06-25)

参考文献数

153

被引用文献数

1

---

Atmospheric oxygen evolution has long been discussed, especially with its relevance to the origin and evolution of life and the planet. Presence/absence of detrital redox-sensitive minerals, iron formations and red beds, behaviors of redox-sensitive elements in paleosols (ancient, subaerially-altered continental rocks) and ratios of carbon and sulfur stable isotopes in sedimentary rocks have been utilized to constrain atmospheric oxygen levels, which can dictate surface redox states, in the distant past, leading to a conventional view that the beginning (2.5–1.8 Ga) and ending (0.8–0.5 Ga) of the Proterozoic were two major periods when the oxygen level significantly increased in the Earth's history. More recent studies adopt multiple sulfur isotopes, iron speciation and trace elements (isotopes) as additional redox proxies. These proxies are not inconsistent with the conventional view, but the magnitude and timing of changes in these proxies are different between proxies and between geological records obtained from, e.g., iron formations, shales and paleosols. Also, the proxies suggest that there may have been transient oxygen increases of uncertain magnitude at 3.3–3.0 and 2.7–2.5 Ga. To better understand atmospheric oxygen evolution, process-based methods which quantify oxygen levels from individual proxies need to be developed to consistently and comprehensively explain multiple geochemical signatures.

著者

平賀 岳彦 渡部 泰史 宮崎 智詞

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.46, no.4, pp.231-242, 2012-12-31 (Released:2017-02-20)

参考文献数

39

被引用文献数

1

---

Investigation of intergranular regions of fine-grained metamorphic rocks using various electron microscopy reveals the presence of intergranular pores previously filled with an aqueous fluid. Such intergranular fluid inclusions exhibit a characteristic shape which minimizes interfacial energy at intergranular regions. The distribution of the inclusions indicates that they were formed from fluid filled intergranular microcracks that ovulated into inclusions due to the initially unstable form of a fluid film at grain boundaries. A simple calculation of interfacial stresses produced by anisotropic thermal contraction of quartz grains during cooling of the quartz aggregate demonstrates that most grain boundaries in crustal rocks experience intense intergranular cracking accompanied by infiltration of fluids. Presence of the fluid filled cracks might explain the observations of low electrical resistivity and seismic wave speeds at middle to shallow crustal depths. The inhibition of the crack formation due to the interfacial stress relaxation in ductile crustal regions results in higher electrical resistivity and seismic wave speeds at greater deep. Intergranular chemical components in mantle rocks are ubiquitously found in mantle xenoliths. We can attribute these components to intergranular melts which were present in the mantle.

著者

荒井 章司 阿部 なつ江 松本 一郎 三浦 真

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.55, no.1, pp.5-30, 2021-03-25 (Released:2021-03-25)

参考文献数

146

---

Chromitites (chromite ores) are reviewed for their importance in magmatism, hydrothermalism, geodynamics and production of resources. The key process for chromitite production is possibly the formation of magmas oversaturated with chromite (or chromian spinel).Production of relatively silica-rich magma during the formation of dunite envelope is coupled with the production of the podiform chromitite. The origin of stratiform chromitites is challenged based on a new idea on the origin of chromite-hosted mineral inclusions, commonly found in all types of chromitites. The chromite-hosted melt inclusions, now characterized by the assemblage pargasite+aspidolite+orthopyroxene, are possibly formed during reaction melting of orthopyroxene within the mantle. Chromite grains in the crustal stratiform chromitites, at least in part, are produced in the mantle stage and transported upward to the magma chamber. Origin of ultrahigh-pressure chromitites has been highly debated, but is still enigmatic. Chromitites of hydrothermal origin have been found and may contribute to redistribution of Cr both in the mantle and in the crust. Production of chromitite ores in Japan is also reviewed. Chromitites serve as a good petrologic marker in both mantle and crustal rocks, and will greatly contribute to our understanding of deep-seated structure and mantle processes in the mantle drilling.

著者

高田 秀重

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2017年度日本地球化学会第64回年会講演要旨集

巻号頁・発行日

pp.222, 2017 (Released:2017-11-09)

---

年間に世界で3億トンのプラスチックが生産されている。その約半分は使い捨てのプラスチックである。廃プラスチックのうち陸上の廃棄物管理からもれた部分が、降雨時の表面流出等により河川、そして海洋へ流入する。ポリエチレンやポリプロピレンは水より密度が小さく、浮いて遠距離輸送される。それらは海洋表層や海岸で紫外線に曝され、劣化し、破片となっていく。劣化、破片化が進み5mm以下になったプラスチックがマイクロプラスチックと呼ばれている1)。これらのプラスチック製品の破片の他に、洗顔料や化粧品の中のスクラブ等のマイクロビーズ2)、化学繊維の衣類の洗濯屑3)、スポンジの削れかすなどの寄与も指摘されている。世界の海洋に5兆個、27万トンのプラスチックが浮遊していると推定されている4)。これらのマイクロプラスチックの地球化学的な意味について本稿では考えてみたい。

著者

石橋 純一郎

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.51, no.3, pp.103-118, 2017-09-25 (Released:2017-09-28)

参考文献数

90

---

A seafloor hydrothermal fluid circulation system develops beneath the seafloor where a magma as heat source and fault systems as fluid conduits are equipped. Seafloor hydrothermal systems act as important intermedia among the lithosphere, hydrosphere and biosphere. Seawater entrained into the seafloor evolves to the vent fluid that exit smokers or chimneys, through the processes during the fluid circulation such as elemental exchanges by water-rock interactions and involvement of magmatic volatiles. These interactions cause hydrothermal alteration of the lithosphere, looking from the opposite perspective. Chemical species dissolved in the vent fluids provide energy sources for biosphere around and beneath the seafloor of hydrothermal fields. Geochemical flux transported into the deep ocean by hydrothermal plumes affects chemical and biological processes in the hydrosphere. Formation of mineral deposits from the hydrothermal fluids leads concentration of specific metal elements resulting from long duration of hydrothermal activity. As hydrothermal vent sites have been discovered ubiquitously in various geologic settings, their diversity especially in geochemical aspects becomes more noticeable and interesting.

著者

野津 憲治

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.19, no.1-2, pp.71-84, 1985-10-15 (Released:2016-11-26)

---

Four topics on "Geochemistry of the crust and mantle" are reviewed. The contents are as follows. 1. Introduction 2. Abundances of the elements (2.1) Crustal abundances (2.2) Chemical composition of the earth (2.3) Cosmic abundances 3. Age determination 4. Partition of the elements (4.1) MASUDA-CORYELL plot: Partition of rare earth elements (4.2) ONUMA diagram: Crystal structure control of the element distribution between solid and liquid phases (4.3) Intracrystalline exchange equilibrium 5. Evolution of the crust and mantle, and mantle heterogeneity (5.1) MASUDA-MATSUI model (5.2) Isotopic evolution model of the crust and mantle (5.3) Layered mantle model and mantle heterogeneity 6. Epilogue

著者

堀口 桂香 中山 貴史 松田 准一

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2010年度日本地球化学会第57回年会講演要旨集

巻号頁・発行日

pp.10, 2010 (Released:2010-08-30)

---

本研究は,2008年岩手・宮城内陸地震震源域周辺にて,地震の前後におけるヘリウム同位体比の時空間変化を追跡したものである.地震発生1週間後から半年毎に計4回,温泉水と温泉ガスを採集し,溶存ガス中のヘリウム同位体比を測定した.その結果と2006年7月に同じ地点でサンプルを採集・測定した結果とを比較すると,地震直後には5カ所の温泉において10-85%の増加,2カ所において11-35%の減少が観測され,1年後には地震発生前の値に戻っていく傾向がみられた.これらの結果は,同地域の震源域の地下に地震波の低速度域が認められるという地球物理学研究と一致しており,地球化学・地球物理学双方の研究結果は整合的であり,深部から上昇してきたマントル起源の流体が地震発生に関与した可能性を示唆している.

著者

小路 翔子 笹木 康平 上田 晃 中本 利正

出版者

一般社団法人日本地球化学会

雑誌

地球化学 (ISSN:03864073)

巻号頁・発行日

vol.50, no.2, pp.97-114, 2016

---

Chemical and isotopic (δD and δ¹⁸O) compositions of 30 hot spring waters and 5 river waters in Okuhida Hot Springs, Gifu, were investigated to examine the geochemical characteristics and geothermal resources. Most hot springs were of meteoric origin and of Na⁺–Cl^-・HCO₃^- and Na⁺–HCO₃^- types with low salinity (less than 30 meq/L). In the study area, meteoric water infiltrates into ground and is heated by magmatic source and enriched in Ca²⁺and HCO₃^- during interaction with underlying carbonate rocks. A part of the hot spring is enriched in CO₂ due to contribution of CO₂-rich volcanic fluid. The estimated underground temperatures by several geothermometers are 150 to 200℃ at the depth of <i>ca</i>. 1 km. The total geothermal resources in the study area are estimated to be <i>ca</i>. 400 MWe for producing the electricity. In the study area, most hot springs have been provided for bathing in hotels and a part of them (60℃, 3,000 L/min) has not been used. We provide this unused geothermal energy to apply for snow melting on road and room heating. For the safety use of geothermal resources in the study area, scaling problem was considered. On the basis of the saturation index of several minerals from the observed chemical compositions of hot spring waters, calcite scale is expected to be precipitated in the reservoir and in the production wells and should be considered to prohibit the precipitation.

著者

板井 啓明 兵部 唯香 田辺 信介

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集

巻号頁・発行日

vol.60, 2013

---

琵琶湖の湖底表層には、マンガン濃集層が広く存在することが知られている。このマンガンは主に酸化物態で存在することから、近年の琵琶湖の貧酸素化により還元反応が進行し、湖水へ大量溶出することが懸念されている。本研究では、琵琶湖北湖盆7地点で採取したコア堆積物と間隙水の化学組成を基に、今後貧酸素化が進行した際のマンガンの形態変化および固-液分配変化を仮定し、拡散モデルを用いて底泥からの溶出フラックスの変化を推定した。その結果、貧酸素化にともなう溶出挙動変化は地点間で異なるものの、底泥からの溶出フラックスとして最大で現在の20倍程度に増加ことが推察された。