著者
正路 徹也 佐々木 望
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.28, no.152, pp.397-404, 1978-11-01 (Released:2009-06-12)
参考文献数
9
被引用文献数
1

The minerals of the scheelite-powellite series containing 0, 0.5, 1, 2, 4, 6, 10, 20, 40, 60, 80 and 100 mole % CaMoO4 have been synthesized. The solid solution of this series was obtained by the slow addition of a Na2WO4-Na2MoO4 solution to a large volume of boiling CaCL2 solution. The fluorescent colors of the precipitate change as follows: blue at the scheelite end, pale blue at 0.5 mole % CaMoO4, white at 1 mole %, pale yellow at 2 mole %, and yellow at 4 mole %; and increase yellow tint up to 20 mole %, but do not show any remarkable change beyond that composition. Compared with the standard color card (Fig. 4), on which the precipitates are put, the composition of scheelite containing less than 10 mole % CaMoO4 can be determined within the accuracy of 1 or 2 mole %.The X-ray powder data show that the 2θ 116 (CuKα)-2θ220 (CuKα) values decrease linearly from 5.23° to 4.83° with the increasing amounts of powellite component in this solid solution. Using this value, the composition can be estimated within the accuracy of 10 mole % CaMoO4. From the synthesis, fluorescent colors and X-ray data, it is inferred that the solid solution of the mineral series continues from the scheelite to powellite ends above a room temperature.
著者
佐藤 源郎
出版者
資源地質学会
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.7, no.25, pp.225-230, 1957-09-30 (Released:2009-06-12)
参考文献数
14
著者
山本 栄一 日隈 四郎 家坂 貞男 有松 憲生 二司 哲夫
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.84, pp.200-213, 1967-08-20 (Released:2009-06-12)
参考文献数
15

The Hashima coal mine of the Mitsubishi Mining Co. is located at the semi-artificial tiny Hashima Island, well known as "Warship Island", about 20 km to the south-west of the Nagasaki Harbour.The mine was put into operation in 1887 and has yielded highest class coking coal ever since. Nevertheless, the mining condition was becoming unfavorable in recent years and new coal fields have been actively searched in this area.Since 1953, many geologists and their assistants collected large number of rock samples from the sea-bottom by means of the specially designed dredger backet. They dived with aqualung to observe directly the outcrops at the sea bottom, and examined heavy mineral frequencies of the rock samples collected. Intensive geophysical prospecting, such as marine seismic prospecting by reflection method with floating cables and pressure sensitive geophones, and sonic prospecting was also introduced, in 1957.Thus, the detailed geological maps could be constructed, and the underground geological structure in this off-shore area was revealed. Several coal seams in the Mitsuse area could be traced at the sea bottom exactly, and the coal reserves were clarified.The Mitsuse area has been mined, since Oct. 1965, 14 months after the previous working area was closed owing to a mining accident. The Mitsuse area produces monthly more than 30, 000 tons of high class coking coal at present.In the Hashima area, there is a large reverse fault, named the Hashima-oki fault. Since the depth of the coal seams beyond this fault is rather shallow and there is a large quantity of coal reserves, this huge area is much promising as the next working area.
著者
古宇田 亮一 小出 仁
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.28, no.150, pp.233-244, 1978-07-25 (Released:2009-06-12)
参考文献数
37
被引用文献数
3

海底で再生カルデラが生じたなら,環状に分布する岩脈群,正断層系,中心隆起構造と海底地辷り堆積構造がその痕跡として残るであろう.秋田県大館東方地域では,後黒鉱期の石英安山岩群と浅熱水鉱床群が,中心の大滝石英閃緑岩体を環状に取り囲む現象が存在する.深沢鉱床などの黒鉱鉱床群も,やや東南にずれるものの,ほぼこの環状分布に沿って,いくつか地下に存在する.鉱床群は環状分布の片側に集中度が高い.いくつかの層準で発見される海底地辷り堆積構造は上下運動の痕跡と考えられ,ボーリング資料による地下構造からは,中心の大滝石英閃緑岩体付近の隆起と,周囲の環状石英安山岩群の内側に陥没構造が示唆される.このことから,8km程度の直径をもっこの環状構造は,中新世の海底にできた再生カルデラの痕跡と考えられ,鉱床生成もカルデラの形成に関連して説明することが可能である.すなわちSMITH & BAILEY (1968)説をKOIDE & BHATFCHARJI (1975)説で解釈し直せば,尖頭的岩漿溜りの上昇で地表付近に10km前後の直径をもつ火山性陥没構造(cauldron)が発生し,環状の断裂系が発達する.この断裂系に沿って鉱液が上昇し,海底下では黒鉱をつくる.続いて,環状分布内に中心隆起が生じ,環状に石英安山岩が貫入―噴出し,その後海底が浅くなるか陸化する.この時に鉱液が環状断裂系に沿って上昇し,後黒鉱期の浅熱水鉱脈鉱床をつくったと説明できる.北鹿地域には,このような環状構造(再生カルデラ)がいくつか存在し,各鉱床群は各々のカルデラに関係して生成したと推測される.
著者
坂井 定倫 大場 実
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.149-165, 1970-05-10 (Released:2009-06-12)
参考文献数
12

A number of gold-silver mines on Sado Island, Onomi, Takachi, Kanoura, Kitaebisu, Sado and Tsurushi mines, belong to the type classified as epithermal fissure-filling deposits. These mines are situated on the western slope of the Osado mountain range of the Island.The Sado mine, the largest gold producer in Japan ever since its opening in ancient age, consists of very many Au-Ag quartz veins which filled fissures in the lower Miocene formations.Main vein fissures are intimately related to the movement of the second order fractures trending east-west. These fractures are formed by the NE-SW trending master fractures, with a wider mineralized zone by virtue of many branch and parallel veins.The developments of vein fissures are observed more prominently in brittle rocks such as shale and bedded fine tuff than in the massive pyroclastic rocks and lava flows.The ore shoots are formed mostly in the lower Aikawa formation surrounding the rhyolite dome which lies in the deeper part of the mine area.Recent prospecting works based on the re-analysis of structural patterns of the mineralized areas have proved the existence of promising new veins, and this will contribute to the revival of the Sado mine, which has been idle for fifteen years.
著者
成田 英吉
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.9, no.35, pp.167-178, 1959-06-30 (Released:2009-12-14)
参考文献数
15

The Kamioka Mine, working the largest lead-zinc deposits in Japan, lies in the eastern corner of the Hida gneiss complex. Around the mine, lenticular crystalline limestone beds are often intercalated among biotite-hornblende gneiss which is generally disposed in a NE direction and has NE fold axes which pitch 45°SW.The ore deposits are closely related to the crystalline limestone beds by pyrometasomatic replacement which attacked some minor folding crests to form typical skarn ores of the so-called "Mokuji ore body". The "Shiroji ore body" is a peculiar type of deposit intimately related to the skarn Mokuji ore body. It carries the distinct features of a hydrothermal deposit and is localized in narrow spaces controlled by fissure intersections which are quite different from those of the Mokuji ore body.The Shiroji ore body includes sphalerite, galena, chalcopyrite, pyrite, hematite, arsenopyrite, and silver minerals as ore, and quartz, chlorite, sericite, and carbonate as gangue. The ore is enclosed in a zone of silicification consisting of quartz-(adularia)-sericite-carbonate. All surrounding rocks have been strongly altered by silicification, sericitization, chloritization, feldspathization and argillization.The fracture system controlling the Shiroji ore body is disposed regularly in three directions, namely, NE, NS and EW. The intersections of the fractures trend NE and pitch 45°SW, and offer excellent room for ore deposition.Based on the field occurrence, the mineral assemblages and the nature of the wall rock alteration, the writer concludes that Shiroji ore bodies were produced under hydrothermal(mesothermal) conditions which followed deposition of the pyrometasomatic Mokuji ore bodies.
著者
吉村 豊文
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.22-27, 1961-03-25 (Released:2009-06-12)
参考文献数
2

A small displacement, about two meters or less, of a manganese ore deposit is called "Hitokase Danso", meaning "one-frame fault". The movement on the fault had evidently occurred before the manganese deposit was formed, and most of the shear zones have been mineralized by various manganese ores. The manganese ore deposit itself, therefore, has not been displaced by the fault movement, although slickensides on such later formed manganese minerals indicate the renewed movement of minor scale along the one-frame fault.
著者
大町 北一郎
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.8, no.27, pp.18-32, 1958-02-28 (Released:2009-12-14)
参考文献数
70

The Inaushi mine, about 10 km west of Engaru town, Kitami Province, is located in one of the epithermal deposits of Northeast Hokkaido. The sedimentary rocks in the vicinity of the mine consist mainly of black shale, sandstone and conglomerate of Mesozoic age, they are overlain unconformably by Neogene Tertiary (Miocene) sediments. The Mesozoic beds are cut by many dykes. The rocks of the dykes are predominantly quartz-porphyrite, andesite and liparite which range widely in composition.The No.3 ore deposit of the Inaushi mine is worked as a source of copper ore and occurs along a fault zone in quartz-porphyry, sandstone, black shale and conglomerate of Mesozoic (Pre-Cretaceous?) age. The deposit consists of several parallel veins, which occur at various distances from the main vein (N 50-Vein). The No.3 ore deposit seems to be associated with parallel dykes of quartz-porphyrite. The veins are characteristically of the composite "chlorite-quartz-copper-vein" type and strike N 70-80°E, and dip 80-90° south. The veins may attain widths of 0.4-0.8 meters. These deposits have been believed to be of epithermal origin. The structure of the veins is classified as follows: brecciated, banded and networked. The brecciated veins usually contain angular fragments of country rocks cemented by a matrix consisting of variable amounts of sulphide and gangue minerals. In some veins, ring ore is observed.The predominant sulphides of the ore deposit are pyrite, chalcopyrite, sphalerite and galena. Other minor minerals are hematite, bornite, chalcocite, marcasite and pyrrhotite. The gangue minerals are chlorite, quartz, calcite and adularia. From the mineralogical association of the ore, the mineralization in the deposit is divided into four stages:1) Quartz-chlorite-pyrite-stage2) Quartz-chlorite-chalcopyrite-pyrite-stage3) Chlorite-sphalerite-galena-pyrite-hematite-stage, and 4) Quartz-pyrite-stage.The ore mainly shows a brecciated and banded appearance. Most of it contains chalcopyrite and pyrite often accompanied by sphalerite and galena, with gangue minerals such as chlorite, quartz and calcite. The brecciated ore usually contains fragments of wall rocks and the banded ore consists mainly of chalcopyrite and pyrite.Paragenesis and texture of ore minerals were studied in detail. Chalcopyrite has occasionally been enclosed in the sphalerite. Also, chalcopyrite within sphalerite occurs as emulsion blebs, commonly in seriate arrangement, and shows definite preferred orientation relative with any one host grain, indicating control by the crystal structure of the sphalerite. Therefore, from the mineralogy of the vein, the No. 3 ore deposit may be classified as fissure-filling veins which belong to the "xenothermal deposits" type (shallow high-temperature condition) rather than the epithermal type deposit.The minor elements in chalcopyrite from sulphide ore of several levels in the N50-vein and also from other chlorite-quartz-copper-vein deposits were determined by spectrographic methods. The results show the presence of Bi and Sn in chalcopyrite from the Inaushi mine, Komaki mine, and Miyatamata mine. The chlorite of the gangue was determined to be aphrosiderite by means of both chemical analysis and X-ray studies.In conclusion, it seems highly probable that the No. 3 ore deposit of the Inaushi mine was formed under high temperature conditions of subvolcanic origin similar to those prevailing in the Inner Zone of Northeast Japan.
著者
小野 広一郎
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.21, no.106, pp.150-161, 1971-05-01 (Released:2009-06-12)
参考文献数
13

The copper deposits, consisting of chalcopyrite, pyrite, sphalerite, galena, quartz, calcite, sericite and others, in the main area of the Kishu Mine occur in the Okochi 'the Itaya and the Taketo formations of the Miocene Miyai Group. They are mainly composed of sandstone, and sandstone and shale.The Miyai Group surrounding the main ore-bearing area has a general strike of N20-40°E and a dip of 10-30°E. The main ore-bearing area is situated in a dome of a large basin of the Miyai. Group. The long axis of the dome is parallel to the general strike of the Miyai Group.Vein fissures of the main mining district are grouped in the following three sets according to the strike directions: i. e N-S, E-W and NW-SE. Intersections between two sets of fissures of the N-S group and the E-W or NW-SE group, can be regarded as the channelways of mineralizing solutions and mineralization centers. The most important intersection is situated in the vicinity of the dome where Josen No. 20 vein meets Josen 9-level North Cross-cut.Five mineralization stages can be recognized. i.e Py, Cu-Py, Pb-Zn, Au-Ag and calcite stages. There are two types of copper ores. The one is associated with chlorite formed during the Cu-Py stage and the other with sericite formed during the Pb-Zn stage. The latter's deposition centers are generally beneath the former's.Silicification, chloritization and sericitization are recongnized as wall-rock alterations.The Cl- content distribution in the deep seated ground-water in the mine well reflects in the geologic structure.Filling temperatures of the minerals mainly measured by decrepitation method are 172-318°C in chalcopyrite, and 160-330°C in pyrite.
著者
池田 則生 肥田 博行 野口 一明 藤原 操
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.33, no.178, pp.97-114, 1982-05-10 (Released:2009-12-14)
参考文献数
34

The tungsten-copper-tin deposit of the Takatori mine is of plutonic vein type and developed in alternating beds of sandstone and shale which constitute Yamizo Group of Triassic age. Detailed examination on the mode of occurrence of the deposit both in the underground and in the field has provided some important informations and suggestions for future exploration. Our observations and conclusions in this study may be sum-marized as follows:(1) Vein fractures in the deposit are classified into two groups, i.e., "Tatehi" group and "Yokohi" group. Fractures of the former in general trend NWW-SEE and steeply dip southward, while those of the latter are almost horizontal but in general gently dip northward. The two groups of fractures constitute a set of conjugate shears under the same stress field, principal stress axes of which being as follows; maximum compressional stress axis (σ1): S25°W30°, intermediate compressional stress axis (σ2): trending NWW-SEE and nearly horizontal, and minimum compressional stress axis (σ3): N30°E60° with angle of shear planes (2θ) of 80°.(2) Three mineralization stages are identified, i.e., wolframite-quartz stage, sulfide-quartz and cassiterite-quartz stage, and barren quartz stage with only pyrite, in chronological order.(3) At Nanabanhi Vein, the champion vein of the deposit, a vertical metal zoning is clearly observed, i.e., wolframite-rich zone, chalcopyrite-rich zone and cassiterite-rich zone in ascending order.(4) The localization of ore shoot appears to be structurally controled by some faults named as No.7 fault, No. 15 fault and W28 fault at-7 level, among which No.15 fault, being located in the central part of the deposit, is assumed to have acted as a channel feeder of ore fluid. All the faults were formed prior to the mineralizations and were probably in active during a certain period after the mineralizations as well.(5) It is suggested that the vein fracture systems were related in origin to the intrusion of a granitic magma. Namely, the uplifting of the southern geologic block with northwestward tilting at the stress field given by the granitic intrusion is considered to have been responsible for the reverse S-shaped regional structure of the area to have resulted the vein fracture systems observed.
著者
アルファロ フルートス
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.38, no.207, pp.15-25, 1988

チリ南部の太平洋沿岸域(Coast Range)南部(南緯39°~42°)の古生層中に,ソレアイト玄武岩熔岩,チャート,堆積岩に伴って銅・亜鉛を主成分とする塊状硫化物鉱床が胚胎している.黄鉄鉱,磁硫鉄鉱と共生する閃亜鉛鉱中のFeS含有量は17.0~18.2mol%であり,変成作用の圧力は約2.5kbと推定される.黄鉄鉱のイオウ同位体比は+2.5%(+0.3~+5.4%)で,日本の別子型鉱床のそれ(+2.7‰)に近い,硫化鉱中のコバルトおよび金の含有量はそれぞれ0.1~0.6%,20~700ppbであった.<BR>微量元素およびREEの分析結果より母岩はoceanicbasaltであることが判るので,この塊状硫化物鉱床は日本の別子型鉱床ないしノルウェーのカレドニアのレッケン鉱床に似ていると結論される.
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

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

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

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
スミルノフ V.I. ボロダエフ Iu.S. スタロスチン V.I.
出版者
資源地質学会
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.18, no.91, pp.284-291, 1968

日本の硫化鉄鉱鉱床<SUP>*1</SUP>の多くは,アルプス地向斜発展期初期段階のものである中新世のスピライトーケラトフフイア岩系の岩石帯に集中している.この種の鉱床の鉱体は,火山砕屑岩層に覆蔽された流紋岩質層の近辺に賦存し,累帯構造を示している.下位の熱水性変質作用を受けている流紋岩中には,交代成微脈―鉱染状硫化物鉱石(珪鉱)が発達している.その上位には塊状の硫化鉄鉱鉱石(黄鉱)が分布している.そしてさらに,海成の成層火山砕屑岩に整合的に覆蔽された高品位多金属鉱(黒鉱―чёрная руда,black ore)が,その上位に分布している.この鉱床は,火山源堆積作用の複合生成物と思われる.すなわち,鉱体下位のものは流紋岩に対する熱水溶液の作用によつて生成し,上位のものは中新世の海底にその熱水溶液が運んできた物質が沈殿して生成したものと思われる.<BR>1940年代になつて,A.ザヴァリツキーはウラルの硫化鉄鉱鉱床について新しい火山源生成説を提起したが,彼は,第三紀火山作用と結びつけた日本の「黒鉱」に関する日本の地質学者たちの考え方(木下亀城,1931)をその中にとり入れ支持していた.しかし硫化鉄鉱鉱床の生成条件に関する考え方が変つてきた現在,日本の硫化鉄鉱鉱床の地質に関するデータは,その火山源熱水―堆積性起源説(Theory of volcanogenic hydrothermal-sedimentary origin)の検討に基本的な支えとなり得るものである.そのために,日本のデータがソ連の地質学者の大きな関心を呼んでいるわけである.<BR>本論文を執筆するに当つて筆老らは次のように分担した.すなわち,1966年秋に日本の代表的な「黒鉱」鉱床を訪れて,研究試料を得てきたV.I.スミルノフは,地質の記載とその他のすべてのデータの全般的な総括(スミルノフ,1967)を行ない,Iu.S.ボロダエフは鉱石試料の顕微鏡的研究結果についてまとめ,V.I.スタロスチンはその試料の物理的性質の研究を行ない,そのデータを提供した.<BR>本論文の執筆は,東京大学の渡辺武男教授と立見辰雄教授,東北大学の竹内常彦教授,その他のきわめて熟達した著名な日本の鉱山地質学者との会合で,大いに刺激された結果である.また,同和鉱業株式会社社長新井友蔵博士とその補佐役の方々から,日本の硫化鉄鉱鉱床の巡検に積極的な協力と援助を受けた.これらすべての方々,および本論文を校閲して下さつたT.N.シャドルンとG.F.ヤユヴレフの両氏に厚く感謝申し上げる.<BR>著者はまた,日本の鉱石試料から得た硫化鉱物中の硫黄同位元素の分析を早く終了するために,V.I.ヴィノグラードフの高配を得た.<BR>当該鉱床の地質を説明する図葉は,日本の鉱山地質学者の資料から借用したが,遺憾ながら原図に明記してないため,その人々の名を示すことができなかつた.
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

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

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
小野 広一郎
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.19, no.97, pp.299-311, 1969-10-20 (Released:2009-06-12)
参考文献数
11

Abundant copper vein deposits of the mine occur in the Itaya formation composed of sandstone and intercalating shalebeds of the Miocene Miyai group. Principal ore mineral is chalcopyrite, and it is associated with pyrite, sphalerite, galena, quartz, calcite, chlorite, sericite, etc. Chloritization, silicification and sericitization of wall rocks are very distinct. Vein fissures of the mining district can be grouped in three sets of strike direction: N-S, E-W and NW-SE groups. Fissures of N-S and E-W group are shear fractures, while those of NW-SE group are tension cracks. The ore-bearing veins of the E-W and NW-SE groups have been mined chiefly for copper ore. Fissures of the N-S group contain a large amount of pyrite but are rather barren of chalcopyrite.Depth zone that comprises the workable extent and ore shoots of each veins is remarkably limited within the sandstone-rich members of the Itaya formation.Th0e Miyai group surrounding the main ore-bearing area has general strike of N20-4°E and dips 10-30°eastward. The main ore-bearing area is situated in a, dome within the northwestern part of a large basin of the. Miyai group. The long axis of the dome is orientated parallel to the general strike of the Miyai group. The ore-bearing area is divided into four districts by the difference of local structures: northeastern, northwestern, southeastern and southwestern districts. Structural and mineralogical features of ore-bearing fissures in each district reflect the difference of geologic structure. A notable difference is that the fissures in the northeastern district run at nearly right angles to the strike of the strata, while those in the southwestern district are parallel to them.Four stages of mineralization can be recognized: the first stage (Cu-Py), the second (Pb-Zn), the third (Au-Ag) and the fourth (calcite).Distribution of the metals deposited in the area are expressed as assay grade multiplied by the width of veins, and iso-metal quantity contours are illustrated on the maps. It seems possible that mineralization centers of each four stages overlap one after another in the southwestern district, while no evidence of coincidence is observed in the northeastern district. Fissures of the N-S group can be regarded as the channelways of mineralizing solutions.Cu and Pb-Zn zones can be depicted successively outwards from centers where two sets of fissures of the N-S group and the E-W or NW-SE group cross each other. These features might be useful for further exploration.