巻号一覧
78 巻, 9 号
選択された号の論文の4件中1～4を表示しています
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山本 芳樹1983 年 78 巻 9 号 p. 313-323
発行日: 1983/09/05
公開日: 2008/08/07
ジャーナル フリーThe Wada-gawa area, central part of the Hida metamorphic belt, consists of diverse gneisses of the upper amphibolite facies, which were later intruded by several small granitic bodies.
Garnet porphyroblasts in pelitic gneisses are replaced by biotite along their rims and cracks, and are separated into smaller parts by biotites films. The replacement proceeds more remarkably in the neighbourhood of the small granitic bodies, suggesting that the replacement is closely related to the granitic intrusion. Each of the separated parts of the garnet shows a reverse zoning in which Fe and Mn contents increase and Mg content decreases from the core to the rim, although the core of some larger garnet is homogeneous. The compositional contour of the reverse zoning is concordant with irregular outline of the resorbed garnet.
The mode of occurrence and the zoning pattern of garnet suggest that the reverse zoning of garnet was formed by volume diffusion in garnet crystal during the retrogression of garnet which was closely associated with the intrusion of small granitic bodies.抄録全体を表示PDF形式でダウンロード (1533K) -
佐藤 岱生, 石原 舜三1983 年 78 巻 9 号 p. 324-336
発行日: 1983/09/05
公開日: 2008/08/07
ジャーナル フリーAbout 320 Tertiary granitoids from the Outer Zone of southwest Japan and the Hidaka Belt of central Hokkaido are statistically compared on major element chemistry. These granitoids occur along the tectonic zones facing fore-arc basin, and have similarities in geological age and opaque mineralogy (il-series). The main conclusions are as follows:
(1) The granitoids from the Hidaka Belt are similar to those from the Outer Zone of southwest Japan, being rich in K2O and FeO but poor in CaO and Fe2O3 compared with the average of Japanese granitoids (Aramaki et al., 1972).
(2) A considerable difference, however, is noted in Na2O content between granitoids of both regions. The granitoids of the Hidaka Belt have higher Na20 content than those of the Outer Zone of southwest Japan. The sodic character of granitoids in the Hidaka Belt may be ascribed to the sodic nature of the source material which is the sedimentary and metamorphic rocks of the Hidaka supergroup that contained originally abundant volcanic materials. The granitoids of the Outer Zone of southwest Japan may have interacted with both the gneissic basement and the Shimanto supergroup having low Na2O and high K2O contents.
(3) TiO2 content of granitoids from both zones are higher than the average of Japanese granitoids.
(4) Al2O3 content of the granitoids of the two zones is similar to that of the Japanese average, but their excess Al2O3 calculated as normative corundum (corundum index) is higher than the average.
(5) In the Hidaka Belt, occurrence of S-type granitoid besides I-type one is suggested from the major element chemistry, which is consistent with recent finding of cordieritebearing granitic rocks from this belt.抄録全体を表示PDF形式でダウンロード (944K) -
鈴木 舜一, 小田 幸人, 大山 良彦, 南部 松夫1983 年 78 巻 9 号 p. 337-349
発行日: 1983/09/05
公開日: 2008/08/07
ジャーナル フリーThe area southeast of the Lake Towada lies in the eastern border of the Green Tuff region, which are characterized by submarine volcanic activities in the Miocene. Recently a number of boreholes were drilled through the Miocene sediments for the exploration of ore deposits. Core samples from these boreholes were used for vitrinite reflectivity study. Lateral and vertical changes in vitrinite reflectivity of the Miocene sediments are illustrated in the sections and plan showing isoreflectivity lines. Vitrinite reflectivity of the Miocene sediments increases rapidly from the east to the west. The isoreflectivity map at the top of the Yotsuzawa Formation shows changes in rank from subbituminous to anthracite at a short distance. Reflectivity gradient of the boreholes in the west of the area is steeper than in the east. Stratiform ore bodies of Kuroko and copper-lead-zinc veins occur in the west of the area. The mineralization were restricted to zones above 2% Rmax at the top of the Yotsuzawa Formation. Isoreflectivity pattern indicates the development of hydrothermal activities associated with the volcanism in the Miocene age.抄録全体を表示PDF形式でダウンロード (851K) -
崔 善奎, 今井 直哉1983 年 78 巻 9 号 p. 350-360
発行日: 1983/09/05
公開日: 2008/08/07
ジャーナル フリー韓国・蔚山鉱山において, 1981年夏に掘削された試錐孔, No. US-8103は興味深い斑銅鉱に富んだスカルン銅鉱石を捕捉した。この鉱石の鉱物学的研究によって,著者らはこのなかから三原鉱 (Cu4FePbBiS6) をみいだした。この論文は,この蔚山鉱山産三原鉱の産状および鉱物学的諸性質を明らかにし,それが原産地である三原鉱山および明延鉱山の物質と類似の鉱物共生を示し,かつ化学組成・X線画折データなどについて、両者が良好な-致を示すことを述べたものである。そして,最後にこの鉱物の成因に言及し,それは鉄・タングステン主鉱化作用に引き続いた後期スカルン形成の時期における多金属鉱化作用の産物であって,これら複雑硫化物・硫塩鉱石の1部にInの濃集が認められることが指摘された。抄録全体を表示PDF形式でダウンロード (2370K)
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