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1992 Fiscal Year Final Research Report Summary

Study of hydrothermal mineralization in Otaru district, Hokkaido, with special reference to acid sulfate alteration.

Research Project

Project/Area Number 02640618
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 鉱物学(含岩石・鉱床学)
Research InstitutionHokkaido University

Principal Investigator

YUI Shunzo  Hokkaido Univ., Fac. Sci., Prof., 理学部, 教授 (10006637)

Co-Investigator(Kenkyū-buntansha) TUCHIYA T  Hokkaido Univ., Fac. sci., Tech. Officer, 理学部, 教務職員 (80088848)
MATSUEDA H  Hokkaido Univ., Fac. sci., Assoc. Prof., 理学部, 助教授 (20108921)
Project Period (FY) 1990 – 1992
KeywordsAkaiwa, Otaru / Asari, Otaru / Acid sulfate alteration / Alunite / Miocene mineralization / K-Ar age / Migration of hydrothermal activity
Research Abstract

The Sea of Japan side of the northern part of Japanese Islands forms a geologic province called the Green Tuff region where occur many ore mineralizations including gold-silverveins, kuroko deposits, and base metal veins. Otaru is located at the northern end of the Green Tuff region. Akaiwa district was main target of this project and Asari district, 13 km southeast of Akaiwa was also studied.
Mt. Shimo-akaiwa(279m above the sea) consists of intensely silicified volcanic rock (andesite?) containing alunite sporadically. At sea-shore, a silicified rock is surrounded by zoned alteration, argillic(mainly dickite) zone, illite(sericite)-smectite zone, chlorite zone, and propylite. The silicified rock contains diaspore crystals up to 2mm in size in the pore. In the argillic zone contains pyrophyllite and/or zunyite. This distribution of minerals seems to be resulted from oxidation of sulfur-containing acid hydrothermal solution.
"Breccia pipes" extend vertically. Inverse grading of silicified clast in a pipe suggests that it was formed by vigorous movements of ascending fluid. "Layered parts" are composed of fine-grained powders of quartz and alunite with normal size grading and seem to be formed in small hot lakes.
Geothermometry using homogenization temperature of fluid inclusion, sulfur isotope fractionation between sulfide and sulfate minerals, and mineral stability gave 200-250゚C.
Two K-Ar ages, 9.7*0.5 and 10.0*0.5 Ma have been obtaind from Akaiwa, and two, 6.1*0.6 and 4.8*0.4 from Asari, all for alunite. Considering younger ages reported from Toyoha, south of Asari, the hydrothermal activity migrated southwards since the Miocene age.

  • Research Products

    (12 results)

All Other

All Publications (12 results)

  • [Publications] YUI,Shunzo: "A systen EPMA data reduction programs using BASIC for Personal computers in 1992" Jour.Fac.Sci,Hokkaido Univ.,Ser.IV. 23(2). 147-158 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yang,Xuan-Zhu: "Chemical compositions and paragenesis of the platinum-group element minerals in the Jinchuan sulfide deposit,Gansu Province,China" Jour.Fac.Sci.,Hokkaido Uuiv.,Ser.IV. 23(2). 287-299 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] AKAMATSU,Kazuko: "Acid sulfate altertion at Akaiwa,near Otaru,southwestern Hokkaido" Hydrothermal ore deposits and wall rock alteration in south-western Hokkaido.29th IGC field trip A04 guide book. 18-23 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] YOSHIKAWA,M: "Texture,Chemical composition and genesis of schreidersite in iron meteorite" Jour.Fac.Sci.,Hokkaido Univ.,Ser.IV. 23(2). 255-280 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] MATSUEDA,H.: "Hydrothermal ore seposits and wall rock alteration in southwestern Hokkaido(A04)" Mineral deposits of Japan and the Philippines,29th IGC field trip guide book. 6. 17-60 (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Jayatiloko,S.: "Preliminary comparison of mineralogy between Sri Lanka and part of East Antarctica" Jour.Nat.Sci.Council Sri Lanka. (1993)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Yui, Shunzo: "A system of EPMA data reduction programs using BASIC for personal computers in 1992." Jour. Fac. Sci., Hokkaido Univ., Ser. IV. 23 (2). 147-158 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yang, Xuan-Zhu: "Chemical compositions and paragenesis of the platinum-group element minerals in the Jinchuan sulfide deposit, Gansu Province, China." Jour. Fac. Sci., Hokkaido Univ., Ser. IV. 23 (2). 287-299 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Akamatsu, K.: "Acid sulfate alteration at Akaiwa, near Otaru, southwestern Hokkaido." 29th IGC Field Trip Guide Book. 6. 18-23 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Yoshikawa, M: "Texture, Chemical composition and genesis of schreibersite in iron meteorite." Jour. Fac. Sci., Hokkaido Univ., Ser. IV. 23 (2). 255-280 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Matsueda, H.: "Hydrothermal ore deposits and wall rock alteration in southwestern Hokkaido(A04). Mineral deposits of Japan and the Philippines." 29th IGC Field Trip Guide Book. 6. 17-60 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Jayatilke, S.: "Preliminary comparison of mineralogy between Sri Lanka and part of East Antarctica" Jour. Nat. Sci. Council Sri Lanka. (1993)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1994-03-24  

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