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

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
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
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
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

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
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
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

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
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
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

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

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
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.