著者

苣木 淺彦 長谷川 修三

出版者

The Society of Resource Geology

雑誌

鉱山地質 (ISSN:00265209)

巻号頁・発行日

vol.2, no.6, pp.185-196, 1952-12-25 (Released:2009-06-12)

参考文献数

49

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The Hayama Mine is situated on the Abiikuma Plateau about 15 kilometers to the southeast of Fukushima City. The district is composed mostly of hornblende biotite granodiorite. However, some hornfels and ultra-basic rocks, such as dunite and diallagite, are present in the form of a roof-pendant. The nickel-bearing minerals, such as niccolite, gersdorffite, pentlandite and nickeliferous pyrrhotite etc., occur as fine grains in the forsterite aggregates, which form a vein-like body in dunite. The forsterite rock is also cut by remarkable black veinlets, composed of the acicular or fibrous crystals of ludwigite. Ludwigite is known to be produced by the chemical reaction of boron- and iron-bearing emanations from granitic magma on some magnesium-bearing rocks such as dolomite and magnesite. Under the microscope, the nickel minerals generally appear in pure crystals, filling up the interstices between the forsterite grains. The niccolite, is rarely rimmed with gersdorffite. Ludwigite is always accompanied by magnetite and chromite which are thought to have been derived from the ultra-basic rock.The paragenesis of nickel minerals-forsterite-ludwigite-chromite is very critical in the interpretation of the ore genesis. This deposit must be studied from two viewpoints, one from magmatic differentation and the other from contact metasomatism.

著者

長谷川 修三

出版者

Japan Association of Mineralogical Sciences

雑誌

岩石鉱物鉱床学会誌 (ISSN:00214825)

巻号頁・発行日

vol.39, no.5, pp.194-203, 1955-10-01 (Released:2008-03-18)

参考文献数

20

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興田産コランダムは珪線石ホルンフェルス中に正長石を伴い,径1cm以下の変斑晶として多数存在する。結晶形はc(0001), a(1120)及びr(1011)より成る六角板状で薄青色を呈する。その比重,屈折率はG4 ?? 180=3.964,ω=1.768,ε=1.761で化学組成は略々Al2O3に相当する。 スカルン帯に豊富に存在する黄褐色の柘榴石の比重,屈折率は夫々G4 ?? =3.831,nD=1.8888であり,化学分析の結果から求めた端成分はAnd 91.9, Gr 4.1, Alm 1.7, Sp 2.3mol%である。尚,本コランダムの成因にっいての一考察を述べた。