<報文>東北地方産ケイ酸マンガン鉱の鉱物学的研究(第24報) : 岩手県大谷山および肘葛鉱山産パイロクスマンガン石について

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Four pyroxmangites from Ohtaniyama and Hijikuzu mines were chemically analyzed and exmained by the X-ray diffraction, optical and DTA methods. The Ohtaniyama material is from the pyroxmangite concentrate in the braunite ore body of Osono bedded manganese ore deposits, in the low grade metamorphosed chert of the Permian age. The end member ratio of pink pyroxmangite is FeSiO_3 6.1,MnSiO_3 84.0,MgSiO_3 4.2,CaSiO_3 5.6 mol. %. Three pyroxmangites of Hijikuzu mine occur as the main constituent of the bedded rhodonitic manganese silicate ore deposits, in the highly contact metamorphosed Jurassic quartzite by the intrusion of the Miyako granitic mass. Pyroxmangite is pink red to brownish red. The ratios of end members of the three varieties of pyroxmangite of "pink red (Hijikuzu-1)", "coarse grained brownish red (Hijikuzu-2)" and "fine grained brownish red (Hijikuzu-3)" are FeSiO_3 19.1,29.9,29.4,MnSiO_3 77.6,64.6,63.8,MgSiO_3 0.1,2.3,3.6,CaSiO_3 3.3,3.2,3.2 mol. %, respectively. Variation in optical properties and unit cell dimensions of Siebenerketten pyroxenoids are presented graphically in binary variation diagrams. In the composition range of 0 to 85 mol. % FeSiO_3 a_0,b_0,c_0,cell dimensions and cell volume shows an appreciable and systematic variation with composition, whereas axial angles (α, β and γ) vary little. The DTA was made up to 1,220℃ in air. Ohtaniyama pyroxmangite shows only one distinct endothermic peak at 1,193℃, and an X-ray pattern taken after heating at 1,220℃ in air showed bustamite and rhodonite lines with some weak lines of jacobsite and tridymite. The iron rich Hijikuzu material (Hijikuzu-2) shows an exothermic peak at 890℃ and a sharp exothermic peak at 1,142℃ followed by a distinct endothermic peak at 1,212℃. The high temperature X-ray pattern of this material in air showed pyroxmangite, braunite, hematite and jacobsite lines at about 950℃, and the phases at higher temperature changes to rhodonite, hematite and jacobsite at about 1,100℃ and rhodonite, bustamite, jacobsite (d^<440>=1.5043A) and tridymite at 1,220℃.
東北大学の論文
1979-03-20

<報文>東北地方産ケイ酸マンガン鉱の鉱物学的研究(第24報) : 岩手県大谷山および肘葛鉱山産パイロクスマンガン石について

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