著者

御幸 和則

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.45, no.249, pp.41-52, 1995-02-28 (Released:2009-06-12)

参考文献数

31

被引用文献数

4

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The Kirishima geothermal area is located in the Kagoshima graben which is a volcanic-tectonic depression. The Ogiri geothermal field is one of the active geothermal zones in the Kirishima geothermal area. A thick pile of volcanic rocks of Pleistocene age, reaching 2, 500m in thickness, deposited in the area. These volcanic rocks overlie the Cretaceous basement rock of the Shimanto group which is depressed to a depth of more than 1, 300m in the area. Features of the geothermal resources in the Ogiri field are of the typical fracture type. The Ginyu fault accompanied by hot water reservoirs is the target for developing geothermal resources in the field.Geological surveys such as predicting underground temperatures, analysing fracture systems, clarifying permeable zone, calculating drilling depth intersecting the Ginyu fault and evaluating characteristics of the Ginyu fault reservoir have been made during the process of exploration and development in the area. The underground temperatures were predicted by the studies on the ditribution of alteration minerals and fluid inclusions. The fracture systems were analyzed by measuring thermo-remnant magnetism of the cores and mineral assembleges of the alteration minerals and quantity of the hydrothermal vein minerals in the cuttings. Based on the results of the fracture analysis, multiple regression analysis were efficiently used to estimate the subsurface location of the Ginyu fault.As a result of the geological surveys, all of the production wells drilled in the Ogiri field intersected the Ginyu fault reservoir successfully, and steam production equivalent to 30 MW of electricity could be secured. On the basis of the informations obtained, excellent reservoir models in the Ogiri field were developed.

著者

石原 舜三

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.56, no.1, pp.95-96, 2006-05-20 (Released:2009-06-12)

参考文献数

11

被引用文献数

4

著者

中山 健 柴田 芳彰

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.65, no.3, pp.133-134, 2015 (Released:2018-08-15)

参考文献数

3

著者

石原 舜三

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.62, no.1, pp.106-108, 2012 (Released:2013-08-01)

参考文献数

7

著者

島田 允堯

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.53, no.2, pp.161-172, 2003-12-04 (Released:2009-06-12)

参考文献数

89

被引用文献数

3

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In the last decade, arsenic contaminated groundwater (>0.01 mg/L) has frequently been detected from place to place in Japan, and has caused serious social problems. The comprehensive surveys and researches have demonstrated that arsenic of natural origin dissolves from the aquifer to groundwater under specific environmental conditions. Concerning the aquifer geology, the arsenic-bearing groundwater is divided into S-type (sediment hosted type) and M-type (metamorphic rock hosted type). Meanwhile, from the viewpoint of dissociation mechanism, the arsenic contamination is classified into three types; .Type 1: Reductive dissolution of iron oxyhydroxide (goethite) and release of adsorbed arsenic into groundwater; Type 2: Oxidation of arsenic pyrite, and Type 3: Arsenic release by the decomposition of organic matter in an alluvial peat layer under reducing condition of the aquifer.Because arsenic takes various forms as source and sink in nature and is sensitive to the environmental conditions, it is important that we should consider the geochemical cycle of arsenic for elucidating the dissolution mechanism and also for the remediation of groundwater at the contaminated sites.

著者

渡辺 寧

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.66, no.1, pp.27-34, 2016 (Released:2018-08-15)

参考文献数

27

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A future perspective of the supply of mineral resources is discussed on the basis of the example of rare earth elements (REE). Rare earth elements have been produced from monazite, bastnäsite, and ionic clay ores mostly in China during the last two decades. However, Chinese resource nationalism over the production and export has made the supply of REE unstable in terms of price and quantity. A possible alternative REE source is phosphate ores, which contain a few amount of REE as impurities with some toxic and radioactive elements. Despite low in REE concentration in phosphate ores, more than 300,000 tons of REE (as oxides), which correspond to more than two times of present-day REE demand in the world, are included in the ores annually produced from the mines for fertilizer production. The recovery of REE with other impurities from phosphate ores is beneficial not only to produce REE but also to avoid pollution in farming lands. While our society shifts from the plundering one to the sustainable one, in which mineral resources would be completely recycled, it is desired to recover all the by-product elements from the major ores in order to decrease the impacts on the environment and trigger innovations in the manufacturing industry.

著者

八幡 正弘 黒沢 邦彦 大津 直 高橋 徹哉 戸間替 修一 川森 博史 毛利 元躬

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.44, no.1, pp.1-16, 1994-02-28

参考文献数

21

被引用文献数

3

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Terrestrial volcanic products and lacustrine deposits of Middle Miocene to Pliocene age are widely distributed in the Monbetsu-Kamishihoro Graben which belongs to the Kuril Inner Arc. The Seta deposit located in the southern extremity of the Graben is classified into a hot spring gold deposit, based upon the modes of occurence.<BR>In the Seta mine area, Middle Pliocene lacustrine deposits of the Ashoro Formation which were accumulated in the Tokachi Basin unconformably covers Late Miocene to Early Pliocene terrestrial volcanic products of the Horokapiribetsugawa Formation. The lacustrine deposits are composed of sandstone, mudstone and siliceous deposits associated with a hot spring gold mineralization. A wide variety of sedimentary structure of the lacustrine deposits is observable in this area ; for detailed investigation, a logging of 80 meters of new diamond drill core (GSH-91-1) was necessary, which revealed the sedimentary structure of the basal part of the deposits and the relationship of the Horokapiribetsugawa and the Ashoro Formations. Siliceous deposits have been divided into 5 types, S-I to S-V. Silica is deposited as silica sinter (S-I) on land and/or temporally on shore near the water line, and also conducted into the cold lake water by the thermal water as a thin bedded siliceous deposit (S-II), because the silica gelation quickly proceeds under the influence of current or wave. The hydrothermal eruption broke up the underlying rocks for breccias like a clastic dike and, as a result, scattered breccias, so-called hydrothermat explosion breccias (S-IV) and/or the accidental silica blocks (S-III) in tuff and sandstone. When the hydrothermal eruption took place intermittently in shallow water, silica was deposited as silica complex deposit with sandstone and conglomerate (S-V)<BR>The hydrothermal activity has been divided into seven stages (I to VII). In the Stage I, just prior to form the lake, the acid hydrothermal activity, began, resulting in the silicified and argillized zones in the Horokapiribetsugawa Formation. Stage II, is characterized by the prevalence of hydrothermal explosion breccias on the land of the northern edge of the lake. As mixing of the ascending acid thermal water with the cold groundwater or interstitial water in the basal part of the lacustrine deposits and the argillized rocks of the Horokapiribetsugawa Formation just under the surface of unconformity, adularia formed in sandstone and argillized tuff breccia with kaolin minerals as an alteration product. In the Stages III and V, the hydrothermal activity increased and silica was deposited on the land and/or on the bottom of the lake resulted in silica sinter, thin, bedded siliceous deposit and siliceous complex deposit. Stages IV and VI-1 are similar to Stage II. It may be inferred that the hydrothermal activity was carried on the shore of the lake or the land. In the Stage IV-2, the silica sinter which deposited to a thickness of about 2 meters on land. The hydrothermal activity has silicified to the surrounding rocks and has formed vertical and horizontal quartz veins in these rocks. In the Stage Vll, the hydrothermal activity was attenuated.<BR>These spots of the hydrothermal activity moved from north to south associated with the gold mineralization.

著者

島崎 英彦

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.59, no.1, pp.73-76, 2009 (Released:2010-06-22)

参考文献数

12

著者

志賀 美英

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.49, no.1, pp.47-62, 1999-02-28 (Released:2009-12-14)

参考文献数

40

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After 1960s the demand of mineral resources has rapidly increased in industrially advanced countries. Since the countries depend on mineral-abundant developing countries for the most required mineral resources, they have a wide-range mineral policy for securing mineral resources steadily. They, in such straitened circumstances, have special interest in deepsea and Antarctic mineral resources. Although the potential of Antarctic mineral resources has been estimated with a wide uncertainty, it appears that the continent contains significant resources, as many previous investigators have pointed out.Antarctica is at present governed by the Antarctic Treaty, which went into effect on June 23, 1961. In June 1988, the Consultative Parties of the Antarctic Treaty (CPAT) adopted the Antarctic Mineral Resource Regime governing the exploration, development and production of Antarctic minerals. The Mineral Regime, however, was strongly resisted by international Non-Governmental Organisations (NGOs) concerned with the conservation of the Antarctic environment. On the other hand, the Non-Aligned Countries declared in the General Assembly of the United Nations that any mineral regime on Antarctica, in order to be of benefit to all mankind, should be negotiated with the full participation of all members of the international community. The Antarctic Mineral Regime, as well as the closed system of the Consultative Meeting by the CPAT, was censured also in many other conferences, e.g. the Conference of Heads of States or Governments of Non-Aligned Countries, the Council of Ministers of the Organisation of African Unity, the Council of Ministers of the League of Arab States, and the Islamic Summit Conference.Thus, the Antarctic Mineral Regime once adopted was upset in November 1989. The CPAT instead adopted the Protocol on Environmental Protection in October 1991. The protocol, which entered into force on January 14, 1998, prohibites any activity relating to mineral resources, other than scientific research, in Antarctica at least for fifty years. In the period of the protocol negotiation, some international environmental NGOs were invited as observers to the Consultative Meeting and played important roles as reliable partners of the CPAT in the constitution of the protocol.

著者

渡辺 寧

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.2, pp.103-122, 2010 (Released:2013-06-14)

参考文献数

63

著者

金沢 康夫 中嶋 輝允 高木 哲一

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.49, no.3, pp.203-216, 1999-12-31 (Released:2009-06-12)

参考文献数

35

被引用文献数

2

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Recent geoscientific data and models for ore geneses of the Bayan Obo REE-Nb-Fe deposits, Inner Mongolia, China were reviewed. The rift system developed in the northern margin of the Sino-Korean massif during the Early-Middle Proterozoic era made a favorite tectonic setting for the depositions of Bayan Obo Group and the ore deposits. A variety of veins and dykes around the deposits occur in the footwall clastic rocks and the basement of migmatites. K-metasomatism and brecciation of hanging H9 shale indicate that the shale could serve as a sealing cap-rock for the deposits (DREW et al., 1992). Data of isotope ages from Sm-Nd, La-Ba, Rb-Sr, Th-Pb, Ar-Ar, and Re-Os methods suggest that there are at least three metallogenic periods: (1) 1, 700 - 1, 260 Ma (Middle Proterozoic); (2) 555 - 370 Ma (Caledonian); and (3) 343 - 298 Ma (Hercynian). In the three periods the first one is of the most important (BAI et al., 1996). C, O and S isotopic compositions together with mineral chemistry and field observations of the H8 dolostone and ore minerals indicate the following possibilities: (1) The dolostone belongs to normal sedimentary carbonate rocks and is not a magmatic carbonatite. (2) The original iron (hematite) ore bodies were formed syngenetically before REE-Nb mineralization. (3) The hydrothermal fluids with an alkaline-carbonatite chemistry were derived from the upper mantle, and printed the REE-Nb mineralization over the original iron bodies. The process of the above (2) and (3) is considered as a composite process of both crustal and mantle source mineralization (CAO et al., 1995). Many geochemical data and field observations are consistent with the composite model for the origins of the Bayan Obo deposit.

著者

中川 充 納 篤 山本 俊一郎 原田 武

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.45, no.254, pp.401-408, 1995-12-31 (Released:2009-06-12)

参考文献数

48

被引用文献数

1

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Platinum-group elements (PGE) in nonmagnetic panned-out detrital samples from the northern Kamuikotan ophi-olitic complex, Hokkaido, was examined by neutron activation method. Their Cl-chondrite normalized PGE patterns are similar to those of ophiolitic host rocks and chromitite. Positive correlation between the iridium and chromium contents imply that iridium-series-PGE anomalies are probably due to chromite-hosted platinum-group minerals. Averaged PGE concentration in the samples from the central Hokkaido (Do-ou) region is almost eight times higher than that from the northern Hokkaido (Do-hoku) region. Based on the chemical analyses and the estimated reserve of chromite, total amounts of PGE included within placer chromite grains are estimated to be 17 kg in the northern Hokkaido, and 245 kg in the central Hokkaido.

著者

亀井 玄人

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.51, no.2, pp.145-151, 2001-12-15 (Released:2009-06-12)

参考文献数

26

被引用文献数

2

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The groundwater of the Mobara gasfield in Boso peninsula, eastern Japan, contains considerable amount, around 100 mg/L, of iodine besides dissolved methane. Twelve groundwater samples from gas-producing wells to the aquifer within the Kazusa Group in Mobara and Naruto districts have been analyzed for iodine, pH, Eh, HCO3-, NH4+, SiO2(aq), δD, δ18O, δ13CCH4 and seventeen elements. There is a good correlation between the concentrations of the dissolved elements to those in marine algae. The principal source of the iodine is believed to be algae buried in the sediments and the iodine has been discharged to the porewater during decomposition of the tissue.The molar ratio of I-/Cl- in the groundwater increases from 1.0×103 to 2.2×103 with changing the depth from 2000 to 1000 meters below the surface and turns to decrease from 2.2×103 to 1.8×103 with going up from 1000 to 500 meters. This tendency may be caused by the variation of buried organisms due to changing the sedimentary environment. The observed variation in the ratio indicates that the iodine discharged in the pore fluid did not migrate significantly after the deposition of the formation.

著者

李 讃熙 朴 喜寅

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.45, no.253, pp.323-329, 1995

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韓国,太白山鉱化帯北部に位置する屯田金鉱山には数種類のPb-Bi-Sb-S系鉱物(Sbコサライト,Sbヘイロフスキーアイト,Sbリリアナイト,Bi車骨鉱,(未詳Pb-Bi-Sb-S鉱物)が産出する.これらPb-Bi-Sb-S系鉱物は方鉛鉱,車骨鉱,四面銅鉱,黄鉄鉱,黄銅鉱,閃亜鉛鉱,エレクトラムなどからなる方鉛鉱に富む鉱石に比較的多量に産出する傾向がある.Sbコサライトの平均元素組成はPb;44.1,Bi;30.7,Sb;5.7,Ag;1.6,Cu;0.6,S;16.7重量%で,硫黄原子数5とした時の化学式はPb<SUB>2.08</SUB>(Bi<SUB>1.41</SUB>Sb<SUB>0.47</SUB>)<SUB>1.88</SUB>(Ag<SUB>0.15</SUB>Cu<SUB>0.15</SUB>)<SUB>0.27</SUB>S<SUB>5</SUB>で与えられる.Biブーランジェライトの平均元素組成はPb;55.5,Bi;6.5,Sb:19.3とS;18.2重量%で硫黄原子数11とした時の化学式はPb<SUB>5.18</SUB>(Bi<SUB>0.60</SUB>Sb<SUB>3.10</SUB>)<SUB>3.7</SUB>S<SUB>11</SUB>で与えられる.Sbリリアナイト,Sbヘイロフスキーアイト,未詳Pb-Bi-Sb-S鉱物の化学組成は,硫黄原子数を6,9,5とした場合,それぞれPb2.94(Ag<SUB>0.14</SUB>Cu<SUB>0.15</SUB>)<SUB>0.3</SUB>(Bi<SUB>1.54</SUB>Sb<SUB>0.40</SUB>)<SUB>1.94</SUB>S<SUB>6</SUB>, Pb<SUB>5.84</SUB>(Ag<SUB>0.15</SUB>Cu<SUB>0.15</SUB>)<SUB>0.3</SUB>(Bi<SUB>1.52</SUB>Sb<SUB>0.38</SUB>)<SUB>1.9</SUB>S<SUB>9</SUB> and Pb<SUB>2.12</SUB>(Ag<SUB>0.08</SUB>Cu<SUB>0.25</SUB>)<SUB>0.34</SUB>(Bi<SUB>0.76</SUB>Sb<SUB>0.93</SUB>)<SUB>1.69</SUB>Fe<SUB>0.23</SUB>S<SUB>5</SUB>である.Sbコサライト,未詳Pb-Bi-Sb-S鉱物およびBiブーランジェライトの化学組成はChang et al.(1980)によって合成されたSbコサライト(C相),Y<SUB>1</SUB>-Y<SUB>2</SUB>相,W相にそれぞれ相当する.アンテモンとビスマスは互いに相関することから,両元素は2PbS-Bi<SUB>2</SUB>S<SUB>3</SUB>-Sb<SUB>2</SUB>S<SUB>3</SUB>系において互いに置換しあっていることが明らかになった.最大Bi/(Bi+Sb)比はSbコサライトでは0.75,未詳Pb-Bi-Sb-S鉱物では0.45,Biブーランジェライトでは0.16であった.

著者

村上 浩康 佐藤 比奈子 石山 大三 石原 舜三

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.61, no.2, pp.129-137, 2011-05-25

参考文献数

23

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High-grade REE ores containing acid-resistant minerals, which are common in the Nolans Bore REE-P-U deposit, Northern Territory, Australia, were analyzed by ICP-MS after decomposition of two different preparation methods before the analyses; Li-borate-fusion in a commercial laboratory and multi-acid digestion in our organization. The result derived from multi-acid digestion method shows higher values on LREE relative to the other fusion method, yet Y and Zr showed us higher values on the fusion method. The high-grade REE ores are enriched in light-REE, especially Ce, La and Nd, with a maximum total REE value around 7 wt %. The quantitative analysis by multi-acid digestion seems highly reliable for a wide range of REE concentration when using suitable dilution ratio and digestion sequence with several types of acids which could totally dissolve acid-resistant minerals such as monazite. On the other hand, analysis by Li-borate-fusion at a commercial laboratory potentially gives lower values than that of multi-acid digestion; a given sample is extremely concentrated in light REE. It is necessary to examine the upper as well as the lower detection limits by a conventional analytical method in a commercial laboratory.

著者

大竹 翼 大友 陽子

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.71, no.2, pp.57-73, 2021-12-22 (Released:2022-08-27)

参考文献数

136

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Iron (Fe) is the fourth abundant element on the Earth’s surface, and it has been mined and utilized for various industrial activities. Whereas average continental crust contains ~5 wt% of Fe (as FeO), the minimum Fe grade for minable ore is 20–25 wt%. Formation of Fe ore deposits requires crystallization of iron as oxides, neither silicates nor sulfides, which occur more commonly in ordinary igneous and sedimentary rocks. There are various geological processes that concentrate Fe and form Fe ore deposits, including magmatic, hydrothermal, and sedimentary processes. Fe ore deposits can be divided into orthomagmatic type (or Fe-Ti-V type), iron oxide-apatite (IOA) type (or Kiruna type), skarn, submarine-hydrothermal, banded iron formations (BIF)-hosted, and phanerozoic ironstone. Production of iron ores, particularly high-grade ores, in the world is currently dominated by those associated with or derived from BIFs, Fe-rich chemical sedimentary rocks formed in Precambrian era. A complication of ore reserves and average grade on various Fe ore deposits over the world demonstrates that a number of large and high-grade Fe deposits belong to BIF-associated and derived deposits whereas some other types of Fe deposits, such as orthomagmatic, IOA-type, and skarn, contain gigantic deposits. Although other hydrothermal and sedimentary deposits contain fairly large deposits, the average ore grades are not as great as those associated with BIFs. In magmatic processes, fractional crystallization may concentrate Fe as magnetite. However, further enrichment of Fe to form Fe-Ti-V or IOA type deposits requires a decrease in SiO2 activity in magma, possibly due to immiscible segregation of oxide melts from silicate melts. Although hydrothermal processes typically precipitate Fe as sulfides, highly oxidized and Cl--rich fluids may cause enrichment of Fe as oxides in some magmatic-hydrothermal systems. Other important parameters to form hydrothermal Fe deposits include CO2 fugacity and temperature for skarn and submarine-hydrothermal Fe deposits, respectively. In sedimentary processes, redox state of seawater is the key parameter However, primary precipitates and geochemical processes that govern the formation of BIFs in Archean is still controversial. Recently, trace element chemistry of magnetite as well as Fe and O isotopes are developing geochemical indicators for Fe ore genesis. There will be need for more case studies to verify the indicators.

著者

中山 健 八田 万有美 西尾 憲二 中川 昌治

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.72, no.2, pp.95-114, 2022-12-22 (Released:2023-11-16)

参考文献数

95

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The recent remarkable development of the information society has brought about a great change in theliterate society. Writing by Chinese ink with an inkstone has become almost obsoleted. However, inkstones are stillone of the Japanese traditional handicrafts that are loved and treasured by calligraphers, painters, citizens who enjoycalligraphy, and arts and crafts enthusiasts. Until now, there has been limited about scientific research on traditionalChinese terms and notations related to inkstones, the functions of inkstones, natural figures on the inkstones, etc.We carried out preliminary petrological and mineralogical experiments of ink stones and reported its functional properties.In addition, domestic ink stone was also reviewed and the production environment was examined. In order to inheritthe unique Japanese traditional craft techniques, further contributions from geology, petrology, and mineralogy areexpected, such as elucidation of precise texture of inkstone and identifying high quality inkstone stone resources.

著者

山本 啓之

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.69, no.2, pp.79-95, 2019-12-16 (Released:2022-08-27)

参考文献数

108

被引用文献数

3

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Deep-sea environments are faced with cumulative effects of many human activities, e.g. accumulation of plastics, overwhelming fishing and resource exploitation, heavy maritime transportation, and effects from climate change. Recently, growing interest in deep-sea mining enhances the activities of engineering development on seabed mining and environmental monitoring, and exploration of mining sites within States Exclusive Economic Zones (EEZ) or in areas beyond the limits of national jurisdiction. Since 2010, attention paid to potential environmental impacts caused by deep-sea mining has been increased, and many workshops and research conferences have been held. In the Western Pacific Ocean, the Nautilus Minerals Ltd. has announced that the sea mound located in Papua New Guinea will be a first site likely to be commercially exploited polymetallic sulfide deposit. The Japan Oil, Gas and Metals National Corporation (JOGMEC) conducts a feasibility project for seabed mining in the Okinawa Trough. In 2015, the leaders’ declaration from the G7 summit in Germany identified the conducting of Environmental Impact Assessment (EIA) and scientific research as a priority issue for sustainable development of deep-sea mining. The EIA protocol developed for deep-sea mining is recognized that it will be a practical component for ensuring effective management and protection of ocean ecosystems. The development of EIA protocols is started in Japan as a national project. This paper describes the current situation of technologies concerning deep-sea environmental assessment and monitoring on seabed mining, and technical background of multidisciplinary approaches for deep-sea environmental survey.

著者

実松 健造 星野 美保子 渡辺 寧

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.62, no.1, pp.17-26, 2012 (Released:2013-08-01)

参考文献数

47

被引用文献数

3

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This study evaluates the potential of scandium resources in lateritic bauxite deposits and lateritic Ni-Co deposits derived from mafic parent rocks. Mafic rocks generally contain more Sc than felsic rocks because Sc replaces iron and manganese in pyroxene and amphibole. Pyroxenite and hornblendite are most enriched in Sc whereas peridotite is poor in Sc. Chemical weathering causes rocks to be enriched in Sc, which behaves as an immobile element, because mobile elements are leached from the rocks. Scandium contents of bauxite depend on those of parent rocks and they are estimated to be ~40 ppm in Indochina Peninsula. Red mud, Fe-rich residue in the process of refinery of bauxite, contains high concentration of Sc. Scandium-bearing lateritic Ni-Co deposits contain higher grades of Sc ores than bauxite and recently have been explored in Australia. As Sc contents of the laterite is controlled by those of parent rocks, pyroxenite-derived laterite may form high-grade Sc deposits (>100 ppm). However, Ni and Co grades tend to decrease in the high-grade deposits in Australia. Large amounts of resources and developed techniques in Sc recovery as a by-product indicate that bauxite deposits and lateritic Ni-Co deposits are prospective Sc resources in the near future.

著者

小島 晶二

出版者

資源地質学会

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.69, no.2, pp.97-109, 2019-12-16 (Released:2022-08-27)

参考文献数

78

被引用文献数

5

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Recent progresses on the iron oxide-copper-gold (IOCG) deposits, especially on principal Chilean deposits, are summarized to clarify metallogenesis and exploration of the type of deposits in Mesozoic extensional subduction regime. The principal composite-mode deposits (Candelaria, Punta del Cobre, Mantoverde) are closely associated with Cretaceous Atacama fault system, and are characterized by the typical Na-Ca-K alteration with the early-stage magnetite (or hematite) and the following Mg alteration with copper-sulfide and gold mineralizations. Fluid inclusion and stable isotope studies suggest that the IOCG deposits were formed by high-temperature hypersaline magmatic-hydrothermal fluids. If the IOCG deposits are generated from FeCl2-bearing magmatic fluids, the spatial-temporal relation between the IOCG and iron oxide-apatite (IOA) deposits is well explained by the magmatic magnetite-bubble segregation model (Knipping et al., 2015b; Simon et al., 2018). Nevertheless, a few problems still remain unsolved in the genetic model including contribution of basinal brines.