著者

奥野 孝晴

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.20, no.100, pp.125-131, 1970-05-10 (Released:2009-06-12)

参考文献数

2

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Since the first discovery of uranium mineralization in the Mesozoic lacustrine. Kwanmon group in 1966, many indications of the uranium deposits had been found in the province of West Chugoku and North Kyushu. This paper mainly presents of the deposits in the Toyota district, Yamaguchi Prefecture, as a typical example of them. The deposits are classified into four types by their modes of occurrence, namely, the dike-type, the fault fracture-type, the sandstone-type and the carbonaceous material-type. The following has been revealed after the geological investigation. (1) The dike-type and fault fracture-type deposits are distributed in a straight line which runs parallel to the Nagato Tectonic Line of NE-SW trend. (2) Most sandstone-type deposits occur within a restricted stratigraphical horizon. (3) The grade of radioactive disequilibrium is closely related with the modes occurrence of the ore. (4) Thuringite in dikes and sandstones plays an important role of concentrating of uranium. (5) Uraninite, pitchblende, autunite, torbernite, uranophane, beta-uranophane and phosphouranylite are identified-in the enriched zones of the deposits.

著者

若林 純一 矢吹 丈輔

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.17, no.82-83, pp.113-120, 1967-04-30 (Released:2009-06-12)

参考文献数

8

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The Yamato mercury mine is located in the central part of Nara Prefecture and one of the oldest mercury mines in Japan. The mine area is composed of plutonic rocks and mylonitic rocks of the post-Palaeozoic period, Tertiary quartz andesite and Quaternary sediments. The ore deposits of this mine are controlled by fissure systems such as EW and NW striking shear fractures, and WNW striking tentional fractures which are considered to be formed by the compression of WNW-ESE direction that is connected closely with the movement of the Median Tectonic Line. The ore deposits exist as a group of stringers, ore-pipe and pocket filling these fissure systems. The main Alterations of the country rocks are silicification, argillization, pyritization, carbonatization and chloritization. Ore shoots are formed where the fissures and veins cross, or where they dip at a low angle. It is considered that these ore shoots are controlled by structures of the fissures and the country rock.

著者

新田 富也 深堀 康昌 山田 毅

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.23, no.118, pp.99-110, 1973-05-25 (Released:2009-06-12)

参考文献数

12

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Several copper orebodies are discovered in the deeper portion of the Mozumi mine during a recent development. Some results of the investigation on the geologic structure, mineralization and occurrence of ore minerals are summarized as follows:1) The Mozumi ore deposits have been developed more than 900 meters in depth. A remarkably vertical zonal arrangement of the ore minerals is observed as follows; in descending order, none mineralized limestone, lead-zinc ore with calcite-quartz (shiroji ore), lead-zinc ore with skarn (mokuji ore), copper-zinc ore with skarn (mokuji ore), copper ore bearing pyrrhotite with skarn (mokuji ore), barren skarn.2) Copper orebodies occur generally in the center of mineralized area.3) Copper ores can be classified into four types by the mineral assemblage. It is observed that the mineral assemblage is simpler in the center of mineralization.4) These copper orebodies are considered to be formed during two mineralization stages. The earlier mineralization stage was mainly lead-zinc, which was associated with small amount of copper. The mineralization of later stage which was overlapped to the earlier stage in some places, was mainly copper.5) The main copper mineral is chalcopyrite. Generally in these copper orebodies, it is observed that sphalerite includes fine grained chalcopyrite and pyrrhotite as exsolution paragenesis6) The iron content of sphalerite in copper orebodies are higher than that of sphalerite in lead-zinc orebodies.7) Two types of pyrrhotite are recognized; One is a monoclinic type and another is a hexagonal type. The hexagonal pyrrhotite occurs usually in the center of the mineralization. In an orebody, the hexagonal pyrrhotite occurs usually at the core. In some cases, it is observed that these arrangements are disturbed and, microscopically, they show exsolution lamellae texture.

著者

澁江 靖弘

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.250, pp.121-127, 1995-04-28 (Released:2009-06-12)

参考文献数

31

著者

苣木 浅彦 鈴木 喜義

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.10, no.41, pp.152-167, 1960-06-30 (Released:2010-03-04)

参考文献数

19

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以上述べた事柄を要約すればつぎのようである.1)与内畑鉱山の鉱床は第三紀中新世上部に属すると思われる黒色泥岩層を母岩とする黒鉱式石膏鉱床である.2)産出鉱物としては石膏のほかに少量の黄鉄鉱,黄銅鉱,閃亜鉛鉱および方鉛鉱の金属硫化鉱物,硬石膏,螢石,重品石および方解石などを随伴する.3)上記産出鉱物の生成順序は第17図のようで,硬石膏,螢石,重晶石および方解石はしばしば石膏にて交代せられている.4)石膏鉱体は塊状を呈し,その中央部は塊状石膏を主とする高品位部であるが,その周辺部は母岩の粘土分を混えて鉱染ないし網状石膏鉱体となり,さらにその外緑部は繊維石膏の細脈を伴う黒色粘土化帯に移化する.5)黒色泥岩層中に挾有される凝灰質泥岩は前者に比して石膏の鉱化作用を蒙りがたく,しばしば部分的にcap rock的な役割をなし,その下盤に接して石膏鉱体を胚胎している.6)母岩の変質は著しい粘土化作用と,都分的な珪化詐用とがあり,揃者は石膏の鉱化作用とほぼ時を同じくして行なわれ,後者はこれに先行するものと考えられる.7)粘土化作用による化学的成分の変化は第2表のごとくで著しいMgOの増加と脱珪作用とが特徴的で,ごの結果苦土緑泥石およびモンモリオナイトの生成がみられる.8)黒色泥岩はこれに挾有される凝灰質泥岩に比し人工鉱液に対し石膏を生成しやすく,かつまた,より容易に溶液の拡散を受けやすい.9)本鉱床産石膏の大部分はCa¨およびSO4′′を含む鉱液の物理的条件の変化にもとづく化学沈澱によると推察され,鉱体はある一定のhorizon付近,あるいはその当時の地表より一定の深度付近に胚胎したものと考えられる.

著者

石原 舜三

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.23, no.117, pp.13-32, 1973-02-25 (Released:2009-06-12)

参考文献数

85

被引用文献数

2

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Molybdenum and tungsten deposits provide clear examples of ores related to granitic rocks. The writer (ISHIHARA, 1971a) has pointed out that tungsten deposits tend to be associated with less acid intrusions than molybdenum deposits and that scheelite (not wolframite) in non-calcareous wall rocks occurs where the source granitic magma is calcic. He also proposed a new scheme of the Mo-W metallogenic provinces of Japan, the Kitakami district of which shows a reverse pattern in lateral zoning of those of the Inner Zone of Southwest Japan (ISHIHARA, 1971b). Fundamental data and reasons for the above proposals taken from the Kitakami district have not yet been 'published. This paper, as a sequel to the previous two papers, describes zonal distribution of the metals and nature of the granitic rocks of the Kitakami district. Genesis of the metallogenic provinces of Japan is discussed in terms of the plate tectonics model.The Cretaceous-Paleogene granitic rocks in the Honshu Island show definitely regional variation in composition. It is basic at one side (either continental or oceanic) and becomes acidic at the other side. This is tentatively called "Lateral differentiation trend", and is shown by changes in regional bulk composition and in ratios of Fe+3/Fe+2, NA/K, Th/K, U/K, Rb/K, etc. of the granitic rocks, and distribution of the Mo-W deposits. One suite of these variation is considered as the most fundamental unit of petrogenetic province. Each province consists of subprovinces such as Mo-, W-, and Barren provinces.The lateral diffentiation trend is continentward in the Inner Zone of Southwest Japan (arrows in Fig. 9), but oceanward in the Abukuma and Kitakami Belts. Hence, the most distinct discontinuity appears some place along the present Tanakura tectonic line. The asymmetrical zoning in the Inner Zone of Southwest Japan (see Table 5) can be explained by a magmatic differentiation model during ascending of granitic magma along a continentward-dipping weak zone in crust or Benioff zone itself. This hypothesis was discussed in this paper in emphasizing role of H2O and differences on volatilities of Cl- and F-complexes. This hypothesis implies that Northeast Japan belonged to a different plate from that of the Inner Zone of Southwest Japan and also the paleo-Benioff zone or the conduit of the granitic magma inclined steeply oceanward at the Cretaceous time.

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.58, no.2, pp.131-138, 2008-05-25 (Released:2010-02-23)

参考文献数

23

被引用文献数

3

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Bismuth can be supplied from two sources: primary Bi-bearing minerals concentrated in Sn-W polymetallic ore deposits, and by-product bismuth from sulfide concentrates from various ore deposits. The first example is best shown by the Shizhuyuan skarn-greisen-type Sn-W polymetallic deposits in southern China, and is still a major source for bismuth. This type of ore deposits occurs in carbonate rocks intruded by an ilmentie-series fractionated granite in a continental margin setting. New discovery of this type in a blind status, as exemplified at Nui Phao, northern Vietnam, is urgently needed, because the remaining ore reserves are only for 18 years.

著者

服部 幸雄

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.11, no.45-46, pp.223-229, 1961-03-25 (Released:2009-12-14)

参考文献数

7

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築別炭鉱は,苫前(とままえ)炭田の北東部に位置し,天北炭田と同じ中新世に属している.基盤は上部白亜紀層で新第三紀層が,不整合に被覆している.新第三紀層は下部から原の沢層・羽幌層・三毛別(さんけべつ)層・築別層・古丹別層に分けられる。稼行炭層は,羽幌層中にあって,炭層の上下盤より烏貝田螺の化石を多産することから,淡水成堆積物であることを示している.羽幌層の上部は,海成層の三毛別層に斜交不整合をもつて被覆されている.築別本坑区域は,築別背斜構造山地の南東側にあつて,西は中の沢断層,北西側は一年山衝上断層,南は熊の沢断層,東側は苫前衝上断層によつて境し,1区域を形成している.この区域内の石炭は,隣接近傍区域に比較して,水分が低く,高カロリーを示している,炭層の下盤には黄鉄鉱と方解石を多量産出するほか,全般的に上下盤に繊維方解石の細脈を伴い,また石炭中にも方解石の薄膜が多量に滲透している.これらの現象から地殻変動の際,断層面や亀裂を通じて,地下から上昇した比較的低温の熱水液が作用し,炭化を促進したものと考える.

著者

丸谷 雅治 東原 雅実 渡辺 寧 村上 浩康 小島 元 Boubou DIOUMASSI

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.55, no.1, pp.59-70, 2005-05-20 (Released:2009-06-12)

参考文献数

23

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The mining sector in the Islamic Republic of Mauritania was the backbone of the country's economy in the 1960s when Mauritania gained independence from France. However, mineral exploration has been limited due to several factors including the limited availability of geological information, poor legal and fiscal framework and lack of mining sector promotion measures as well as the vast scale of the country, severe climate and lack of infrastructure.In response to the request of the Mauritanian Government, Japan International Cooperation Agency conducted "the Study on the Strategic Plan of Mineral Resource Development". A geological survey was implemented from November 2003 to March 2005 in the areas of mineral potential in Mauritania with the purpose of promoting domestic and foreign private investments in the exploration of mineral resources.Mauritania comprises five geological provinces. These are the Reguibat Shield, Taoudeni Sedimentary Basin, Tindouf Sedimentary Basin, Mauritanides and Atlantic-Coastal Sedimentary Basin. Major metal ore deposits are distributed within both the Reguibat Shield and the Mauritanides.In the central area of the Reguibat Shield, magnetite formations occur in the Archean groups and large-scale highgrade hematite banded-iron formations occur in the lower Proterozoic groups. These deposits are the sources of iron ores that support Mauritania economy. In the southwestern area of the shield, epithermal; and mesothermal gold-bearing quartz network and disseminated deposits (e.g.Tasiast gold deposit) occur in banded iron formations (BIFs) of the Archean greenstone belt. Moreover, gold-bearing quartz vein deposits (e.g.Tijirit Ator gold deposit) occur in the basalt and ophicalcite units.The Mauritanides is most significant in copper and gold mineralization among the five geological provinces. These comprise a carbonate replacement magnetite-bearing copper and gold deposits and prospects (e.g.Guelb Moghrein deposit), copper and gold-bearing quartz veins in mafic schist and carbonate (e.g.Tabrinkout prospect), copper (and gold)-bearing quartz veins in andesitic to basaltic volcanic rocks (e.g.Indice 78 and Oudelemguil prospects) and disseminated copper deposits (e.g.Kadiar). The other important deposit type is orthomagmatic PGE-bearing chromite deposits in serpentinite (e.g.Guidimaka).In the future, it is desirable that exploration and development focus on gold deposits in the Reguibat Shield, and copper and gold deposits and platinum-bearing chromite deposits in the Mauritanides.

著者

村上 浩康 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.58, no.2, pp.V-VI, 2008

著者

角田 謙朗 清水 正明

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.250, pp.111-120, 1995-04-28 (Released:2009-06-12)

参考文献数

15

被引用文献数

3

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Metallic mineralization in the Suehiro vein and its neighbouring veins of the Otome deposit was described. The metallic minerals of the Suehiro vein and its neighbouring veins are ferberite, pyrrhotite, less pyrite, chalcopyrite, sphalerite, molybdenite 2H, goethite, arsenopyrite, cubanite, Ag, Sb-bearing cosalite, bismuthinite, native bismuth, ingodite, Bi-bearing boulangerite, izoklakeite etc.The mineralization sequence at Otome can be divided into three stages, based on microscopic observation, EPM analyses and fluid inclusion data: Stage I (W mineralization), Stage II (sulphides and sulphosalts), and Stage III (hematite and goethite). Further, the stage II is subdivided into three substages. The fluid inclusion homogenization temperatures ranged from 350°to 250°C for stage I, from 330° to 150°C for stage II and lower than 150°C for stage III.Temperatures and sulfur activities of stage II mineralization at Otome are estimated as 330° to 150°C, and -11 to -20 in log aS2 (atm.), based on the FeS contents of sphalerite, mineral assemblages and fluid inclusion data.

著者

松田 時彦 中村 一明

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.20, no.99, pp.29-42, 1970-03-02 (Released:2009-06-12)

参考文献数

56

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A genetical classification of volcanic clastic deposits is proposed in this paper, which is based on the following four principal criteria:1) place of the eruption by which the material was broughtinto the transporting media : W (subaqueous) or A(subaerial), or O(when it was unrelated directly with the eruption).2) kind of media in which the material was transported to the depositional place : W (water) or A(air) or O(absence of media; this is used for some lava flows and dense landslide deposits).3) place of deposition : W(subaqueous) or A(subaerial).4) mechanism of transportation and settling : F(fall) or R(roll) or T(turbulent flow).Any volcanic clastic deposits might be designated as WWW-T, AAW-F and so on, by putting the result according to the four criteria in a descending order. For lava flows(L), the same principle of classification is applicable, e. g., as WOW-L (or WWW-RL, when it is necessary to indicate rolling(R) mechanism of the emplacement in W media). By the use of O in the first term, this classification also applies to normal clastic sediments, e.g. OWW-T for turbidity current deposits.Discriminating features for each kind of water-laid volcanic clastic deposits are described and several examples are presented.The proposed classification concerns mainly with a sedimentary body as a whole, and not with. descriptive features of particles. Parallel usage of the classic descriptive terminology with the proposed one is recommended, as AAW-F tuff, WWW-T tuff breccia, or tuff breccia (WWW-T), etc.,

著者

磯部 清 保科 恒二 苣木 浅彦

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.17, no.81, pp.22-37, 1967-02-28 (Released:2009-12-11)

参考文献数

13

被引用文献数

1

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The Isobe Koyama mine is situated at about 30 kilometers northwest of Yamagata City and is producing copper and gold ores. The district is composed mainly of Miocene pyroclastic rocks and their lava flows of intermediate to acid type with some mudstone. The ore deposits of this mine consist of twelve bodies which occur in mudstone, muddy tuff, and green tuff. They are of an epithermal type and occuring veins, stockwork or as disseminating bodies. Native gold, chalcopyrite, sphalerite, pyrite, and galena, are the principal ore minerals, associated with such gangus minerals as quartz, kaolin, chlorite, barine and carbonate minerals.Native gold occurs in intimate association with quartz, kaolin, sphalerite and chlcopyrite. The ore comprising chalcopyrite, sphalerite chlorite and quartz is often so rich in gold that its gold tenor is more than one kilogram per ton. However, the grade of silver in the ore is always less than that of gold. The gold-silver ratio is a characteristic of the ore from the mine in comparison with that of the ores from the so-called epithermal gold-silver deposits in which the tenor of silver is usually ten or several ten times of that of gold.The vertical zoning of ore deposit is obvious, often divided into the following five zones from upper to lower : 1) quartz-kaolin zone, 2) quartz-kaolin-sphalerite zone, 3) sphalerite zone, 4) sphalerite-chalcopyrite zone and 5) chalcopyrite zone. The native gold occurs in the zones 1), 2), 3) and 4), especially richest in zone 4). In zone 5 ), the tenor of gold rapidly decreases to less than 2 grams, per ton. This zoning is also found in lateral derection. The central zone is the chalcopyrite zone, which may indicate a center of mineralizaton in this mine. Also, the fissures filled with ores seem to be mostly tension fractures, judging from their pattern.

著者

尾西 明生 松木 正義 小林 直樹

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.23, no.118, pp.119-136, 1973-05-25 (Released:2009-06-12)

参考文献数

19

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The oldest rocks of the Hirase mine area are various gneissose and granitic rocks of the so-called Hida Complex. They crop out in the northeastern and southwestern parts of this area. The Jurassic to Cretaceous Tedori Formation overlies these rocks uncomformably in the southwestern part of this area. The Cretaceous Nohi Rhyolites Group is most extensively distributed in this area. It is composed of acidic welded tuffs intercalated with rhyolite lava, its tuff and tuff breccia, and mudstone.Granitic rocks, K-Ar ages of which are about 60 m.y., intrude the Nohi rhyolites. They crop out as several. stocks along the Sho-gawa (river) and are called "Shirakawa Granites." Fine-to medium-grained biotite granite and hornblende-biotite granodiorite are their major facies. The Shirakawa granitic rocks show contact aureoles in the surrounding Nohi rhyolites. Andalusite-bearing assemblage is seen around some of the plutons, such as Hatogaya and Hirase stocks. Dykes of quartz diorite porphyry, hornblende andesite, pyroxene andesite and basalt occur in these stocks mainly along fault zones.Metamorphic rocks of the Hida complex thrust up to the Nohi rhyolites along the Morimo tectonic line. It strikes north-northwest. A similar fault zone passing through the Mihoro dum reservoir is called "Mihoro tectonic line." There are many faults of NW-trend diversing from the Mihoro tectonic line, some of which cut throngh the Hirase granitic stock.There are many kinds of mineral deposits in the area, namely Cu-Pb-Zn veins in the Fcdori formation, Au-Ag quartz veins in the Nohi rhyolite, graphite deposits in the Hida complex and molybdenite-quartz veins in the Shirakawa stocks. Yet, only molybdenum deposits, those of the Hirase mine in particular, are productive. The Hirase mine is one of the most important molybdenite mines in Japan.The Hirase deposits are composed of 29 molybdenite-quartz veins. The veins strike N-S to NNE and dip steeply west. Productive veins occur in the marginal part of the Hirase stock. The granitic rocks of this part are very heterogeneous and become homogenous toward the interior. The veins also become poor or thin out in the interior.Molybdenite occurs along walls of quartz veins as fine-grained crystals or very coarse-grained cuhedral ones. The latter predominates in drusy parts of the quartz veins and accompanies coarse-grained calcite crystals in some places. Molybdenite seams occur in some parts of the altered Nohi rhyolites. Molybdenum grade of this ore is very low, 100 to 200 ppm, but the quantity is large. The amount of MoS2 in the altered rhyolites at Kitani (about 3 km north of the Hirase mine) is estimated about twice as much as the total historical production of the Hirase mine. Molybdenites in any mode of occurrence have been recognized in rocks between the Morimo and Mihoro tectonic lines.

著者

野村 拳一 谷 藤吉郎

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.31, no.166, pp.99-114, 1981-06-05 (Released:2009-06-12)

参考文献数

6

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The Toyoha mine is located in the geothermal area of Southwest Hokkaido, Japan. The geothermal surveys revealed the presence of very high heat flow areas widely spread over the ore deposit in the Neogene system. The heat flow amounts to 25.7 HFU (heat flow unit), about ten times higher than we expect generally in the Green-tuff region of Japan. Notwithstanding, few hot springs and vapor fumaroles are found around the area and neither prospect tunnels nor drillings have ever disclosed any conspicuous underground hot-water reservoirs.On the basis of the geothermal data obtained from the borehole temperature measurements, it is proved that the temperature distribution has a clear tendency to increase southeastwards and vertically downwards. The source of the high heat flow concerned is presumed as a kind of hot dry rock.The mining operation will be concentrated on the conspicuously high heat flow areas in the future. Thus it is an important problem how to lower the temperature at the underground working site. For the purpose of obtaining the basic data for the future exploration and development in hot areas, the present study aims to draw a possible limit of exploitation by computing the heat balance in tunnel.

著者

鞠子 正 河田 真伸 三浦 充 小野 周平

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.46, no.6, pp.337-354, 1996-12-01

参考文献数

47

被引用文献数

10

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神岡鉱山茂住スカルン型Zn-Pb-Ag鉱床は飛騨片麻岩類の結晶質石灰岩中に産する,その鉱化プロセスは5期に分けることができる.最初の単斜輝石―亜鉛―鉛鉱化期は第1ステージ(400-330℃)での大量の単斜輝石(Di<SUB>10-35</SUB>Hd<SUB>43-75</SUB>Jo<SUB>11-35</SUB>)の生成に始まる.これに伴って少量のグランダイト系ざくろ石(Ad<SUB>16-78</SUB>),方解石,石英,含銀・蒼鉛方鉛鉱,自然蒼鉛,輝蒼鉛鉱, Ag-Pb-Bi-S系鉱物および鉄に乏しい閃亜鉛鉱(3-8 FeS mole%)が晶出する.この期の第2ステージ(320-240℃)は,第1ステージに晶出が始まった硫化鉱物生成の最盛期となる.第2ステージ末期には鉱化流体の鉄濃度が上がり早期生成の単斜輝石および閃亜鉛鉱の一部を交代して,それぞれヘデンベルグ輝石質輝石(Hd<SUB>59-88</SUB>)と鉄に富む閃亜鉛鉱(9-14FeS mole%)を生成している.数の方解石―石英―鉛―亜鉛鉱化期の第1ステージ(400-300℃)には早期方解石,早期石英および鉄に乏しい閃亜鉛鉱(3-7 FeS mole%)が含銀・蒼鉛方鉛鉱,自然蒼鉛,輝蒼鉛鉱, Ag-Pb-Bi-S系鉱物を伴い石灰岩あるいは一部の単斜輝石―亜鉛―鉛鉱を交代して生成した.第2ステージ(300-230℃)には,浸透してきた鉄に富む鉱化流体が早期の閃亜鉛鉱を一部鉄閃亜鉛鉱(7-21 FeS mole%)に置換し,少量の黄銅鉱,黄鉄鉱磁硫鉄鉱,硫砒鉄鉱磁鉄鉱を生成した.また含銀・蒼鉛方鉛鉱,自然蒼鉛,輝蒼鉛鉱, Ag-Pb-Bi-S系鉱物の晶出もひき続いた.第3ステージ(230-150℃)にはいると,鉄に富む閃亜鉛鉱(10-14 FeS mole%),含銀四面銅鉱とともに後期方鉛鉱(銀に乏しい)が生成された.このステージの末期には少量の赤鉄鉱が,後期方解石,後期石英,緑廉石とともに生じている.第3のアクチノ閃石―銅鉱化期は早期に形成された単斜輝石不毛スカルンおよび単斜輝石―亜鉛―鉛鉱に対する加水分解および鉄・銅付加作用により特徴づけられる.すなわち,鉱床下部で単斜輝石はアクチノ閃石により広く交代され,これに伴い石英,硫石比鉄鉱,磁鉄鉱,黄鉄鉱,磁硫鉄鉱,黄銅鉱,鉄閃亜鉛鉱などが晶出した.第4の石英―方解石―銅鉱化期および第5の石英―銀鉱化期の鉱化作用は局部的である.以上の各鉱化期の鉱化作用は,熱源としての火成岩は共通しているが,それぞれ独自の通路を持った循環熱水系により行われたと考えられる.

著者

与良 三男

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.17, no.82-83, pp.107-112, 1967-04-30 (Released:2009-06-12)

参考文献数

3

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The Myoho mine is located in the southern part of Kii peninsula, southwestern Japan. Geology of the mine area consists of sandstone, shale and breccia of Miocene age, and of the Kumano acidic igneous, complex. The Miocene formation is divided into K, A, B and C beds in ascending order. The ore deposits of the mine are chalcopyrite-pyrite-calcite-quartz-chlorite veins, partially containing chalcocite, bornite, sphalerite and galena, in the Miocene formation, The ore shoots are mostly bound in sandstone of C bed. The Kumano acidic igneous complex consists of rhyolite and granite porphyry. The rhyolite forms a large ring dike. It runs at the northern part of the mine. where it branches off several minor dikes. Vein fractures are intimately related to the, ring dike and the branches., Granite porphyry covers the Miocene formation and forms a part of the ring dike. The igneous rocks intruded and extruded prior to the vein formation. The ore deposits were formed in three stages; 1 st stage : Deposition of pyrite, calcite, quartz and chlorite with small amount of chalcopyrite ; 2 nd stage : Deposition of chalcopyrite, pyrite, calcite, quartz and chlorite ; and 3rd stage : Deposition of chalcocite, bornite, chalcopyrite and pyrite.

著者

浜辺 修二 野納 敏展

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.26, no.136, pp.93-104, 1976-05-31 (Released:2009-06-12)

参考文献数

17

被引用文献数

2

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The Kamaishi Mine is one of the major producers of copper-iron ores of skarn type in Japan. In this paper the geological structure of the Kamaishi mining district is described.The Kamaishi mining district is located in the Southern Kitakami terrain with abundant limestone near the boundary to the Northern Kitakami terrain with abundant chert. The district is covered by Paleozoic and Mesozoic formations intruded by igneous rocks of Early Cretaceous.The geological structure of the Paleozoic formations is characterized by a large anticlinolium trending N-S. The deformed Paleozoic formations are covered unconformably by Mesozoic Maginouchi Formation and Ganidake igneous complex is emplaced into the axial part of the anticlinolium. At a stage between the deposition of Maginouchi Formation and the intrusion of Ganidake igneous complex, fault movement occurred resulting in the separation of the area into several geological blocks. Eastern wing of the anticlinolium was displaced downward several hundred meters from the western wing by Nakanosawa fault.The ore deposits are formed at the neighborhood of the contact of Paleozoic limestone and Ganidake igneous complex. The igneous complex consists of Ganidake granodiorite, diorite, diorite porphyry, gabbro and monzonite. The diorite porphyry is intruded along thrusts and faults providing with favourable condition for skarnization and metallic mineralization of the western orebodies of the Kamaishi deposits. "Sennin porphyrite" which has been considered as a member of Ganidake igneous complex was ascertained to be pyroclastics of Carboniferous Tsuchikura Formation. After the intrusion of the Ganidake igneous complex Kurihashi granodiorite was emplaced. Ganidake granodiorite body swells downward while Kurihashi granodiorite body pinches in the depth. This suggests that the former is exposed in its upper level while the latter is deeply eroded.

著者

KOVALEVSKII Alexander L. NEFEDEV Michail A. LANDA Will E.

出版者

The Society of Resource Geology

雑誌

資源地質 (ISSN:09182454)

巻号頁・発行日

vol.44, no.248, pp.429-438, 1994

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潜頭貴金属鉱床ゾーン,南部タイガの丘陵地域の鉱床の探査や地質構造マッピングには,生地球化学,生地球物理学,地質考古学を組み合わせると大変効率的である.もっとも効率的な方法は,生地球化学的探鉱(NBE)と生地球化学的探査(NBP)である.ブルドーザーによって100-200mの長さをもつ16の溝を掘って調べた通常の土壌と地質の調査により詳しい探鉱の行われていたところで,これらの方法を用いたところ160の銀の生地球化学的異常(SOBA)と10の金と6つの白金属の強い生地球化学的異常が見いだされた.銀含有量が100-3,000ppmの15のSOBAを調べたところ3,300-6,000ppmのAgをもつ9つの鉱体, 1-50ppmの銀と,金,白金属を含む33の銀を含むゾーンが見いだされた. NBPを用いて100-3,000ppmのSOBAのところで, 4-10mの溝を掘って再調査をしたところ15の銀の鉱床が見つかった.植物サンプルを1-3m間隔で採集し, NBPを用いて51, 35と15の銀の異常(SOBA)をもつ3つの有望な銀鉱床が見つかり,植物の灰の中に70-3,000ppmの銀を含むことがわかった.最初の探査段階で生地球化学プロファイルとともに生地球物理学と地質考古学を共に用いることが推奨される. NBPは,鉱体の全体を知ることと,地表での地質構造調査に基づいて鉱床の様子を知るのによい方法である.

著者

石原 舜三 柴田 賢

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.22, no.111, pp.67-73, 1972-03-29 (Released:2009-12-14)

参考文献数

33

被引用文献数

1

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近年に対立のみられる生野―明延鉱床区鉱化時期について,新第三紀鉱化作用の提唱から現在に至る研究史を概観し,問題点の指摘とその解決のためにK-Ar法による年代測定をおこなった.明延鉱床における鋸化後の岩脈は新第三紀鉱化作用の時期を示さず,また生野鉱床における弱鉱化を受けた鉱化前の岩脈の年齢測定からもその鉱化作用が白亜紀後期~古第三紀の花崗岩質岩類に関係する可能性を暗示する.以上から生野―明延鉱床区の新第三紀鉱化作用が否定された.また生野鉱床における鉱化後デイサイト岩脈は角礫岩脈である可能性を指摘した.