| 概要 |
Remarkable zonal arrangement of magnetite ore and skarn is observed in the Sampo mine, Okayama Prefecture. Zonal arrangement in Yoshiki No. 1 ore bodies at 9L is summarized from granite-side to marble...-side as follows: granite→hornfels→banded Pyroxene skarn→iron -wollastoni te skarn→green pyroxene skarn→iron-wollastonite skarn→white skarn →garnet skarn→magnetite ore→“Ashinaga”→marble. Iron-wollastonite is accompanied intimately with hedenbergite, and both the minerals occur as monomineralic seam and/or monomineralic zone in the skarn. Iron-wollastonite and clino-pyroxene skarns have been intensely folded concordantly with marble which shows a complicated folding structure, and both extensions are cut by granite intrusives. A close paragenetic relation between iron-wollastonite and hedenbergite is observed in the field as well as under the microscope. Although wollastonite is associated with ferrosalite-hedenbergite series of wide compositional range, iron-wollastonite with 17～19 mol. % (Fe, Mn)SiO_3 is associated with pure hedenbergite exclusively. On the other hand, by comparison of three pairs in Skye, Hijikuzu and Sampo mine, it is inferred that there is a certain rule for Mn partition between iron-wollastonite and hedenbergite judging from the parallel tie-lines. The occurrence of iron-wollastonite and clino-pyroxene skarns suggests that both the minerals were primalily formed by the thermal metamorphism of granite intrusion. The iron-wollastonite and clino-pyroxene skarns were altered to white skarn, which consists of andradite and wollastonite, under the effect of magnetite-andradite-fluorite mineralization.続きを見る
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Mendeley出力
