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Study on Gold Ore Genesis in Volcanic Island Arc

Research Project

Project/Area Number 04402044
Research Category

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

Allocation TypeSingle-year Grants
Research Field 資源開発工学
Research InstitutionKYUSHU UNIVERSITY

Principal Investigator

IZAWA Eigi  Faculty of Eng., Kyushu Univ., Professor, 工学部, 教授 (50037751)

Co-Investigator(Kenkyū-buntansha) HARA Tsuyoshi  Faculty of Eng., Kyushu Univ., Research Assoc., 工学部, 助手 (20159099)
NAKAE Yasuo  Faculty of Eng., Kyushu Univ., Research Assoc., 工学部, 助手 (90253476)
WATANABE Koichiro  Fac.of Eng., Kyushu Univ., Assoc.Prof., 工学部, 助教授 (10182916)
EHARA Sachio  Faculty of Eng., Kyushu Univ., Professor, 工学部, 教授 (10002346)
Project Period (FY) 1992 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥20,200,000 (Direct Cost: ¥20,200,000)
Fiscal Year 1994: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1993: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 1992: ¥14,300,000 (Direct Cost: ¥14,300,000)
KeywordsVolcanic arc / Hydrothermal system / Gold deposits / Magmatic material / Hydrothermal alteration zone / Laser-sampling ICP-MS / 変質帯 / 火山活動 / 放射年代 / 熱水変質 / 九州 / 微量金分析 / 宮崎層群
Research Abstract

During evolution of island arcs and associated magmatic activity, several kinds of metallic and nonmetallic mineral deposits are formed in the hydrothermal systems constructed in the upper crust. Recently it is recognized that epithermal deposits are an important source of gold. This study focused on Kyushu, which can be considered as an ideal example of volcanic arcs, and goal was to clarify the relation between igneous activity and gold mineralization. Results of this study show that the sites of gold mineralization are volcanic geothermal system and that the validity of exploration based on the geothermal model was confirmed.
1. Ages of volcanic activity and gold mineralization
(1) Age determinations for volcanic rocks in gold areas indicate that magnetite series magmatism in southern Kyushu begun about at 10 Ma.
(2) Age determinations for gold deposits in southern, central and western Kyushu clarified that gold mineralization in Kyushu occurred mainly in Pliocene and Pleistocene and that hydrothermal activity and mineralization occurred about 0.5 Ma after the initiation of volcanism in each volcanic center.
2. Hydrothermal alteration and geochemical studies of ore forming minerals
(1) Zonal arragements of hydrothermal alteration in several gold mineralized area show that mineralization occurred in the transitional part from the mixed layr mineral zone to the sericitecholorite zone in the center of a hydrothermal system.
(2) Trace gold was analyzed using laser-sampling ICP-MS for pyrite from the Akeshi and Kushikino deposits.
(3) Ar gas in the ore quartz from the Hishikari deposit was investigated and magmatic sign was not detected.
3. Models for epithermal gold deposits
(1) Possibility of the porphyry copper deposit existing beneath the Nansatsu deposits was examined.
(2) Problem of presence of gold rich basement/magma was investigated by analyzing trace gold in various rock samples from Kyushu using graphite furnace AA and LA-ICP-MS.

Report

(4 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report
  • 1992 Annual Research Report
  • Research Products

    (17 results)

All Other

All Publications (17 results)

  • [Publications] IZAWA,Eiji: "K-Ar ages and the initial Ar isotope ratio of adularia、 quatz veins from the Hishikari gold deposit,Japan" Resource Geology SpeciAl Issue. No.14. 63-69 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] IZAWA,Eiji: "Mudstores in a hydrothermal eruption crater above the gold-bearing system of the Yamada deposit at Hishikari,Japan" Resource Geology Special Issue. No.14. 85-92 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Watanabe,Koichiro: "Fission track ages of Plio-Pleistocene vokanic rocks in the Okuchi region,southern Kyushu,Japan" Gecthermal Res.Rep.Kyushu Liniv.No.3. 98-110 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 松尾哲也: "大分県野矢・滝上地域の熱水変質帯" 九大地熱研究報告. 第3号. 111-122 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] 江原幸雄: "冷却するマグマ直上に発達するマグマ性高温地熱系-九重火山におけるケーススタディー-" 地質学論集. 第43号. 169-177 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] E.IZAWA: "K-Arages and the intial Arisotope ratio of adularia-quartz veins from the Hishikari gold deposit, Japan" Resource Geology Special Issue. No.14. 63-69 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] E.IZAWA: "Mudstones in a hydrothermal eruption crater above the gold-bearing vein system of the Ymada deposit at Hishikari, Japan." Resource Geology Special Issue. No.14. 85-92 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] K.WATANABE: "Fission track ages of Plio-Pleistocene volcanic rocks in the Okuchi region, southern Kyushu, Japan." Geothermal Res.Rep.Kyushu Univ.No.3. 98-110 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.MATSUO: "Hydrothermal alternation in the Noya-Takigami geothermal field, Oita Prefecture." Geothermal Res.Rep.Kyushu Univ.No.3. 111-122 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] S.EHARA: "Magmatic hydrothermal system developing just above a cooling magma-A case study of Kuju volcano, Central Kyushu, Japan-" Mem.Geol.Soc Japan. No.43. 169-177 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] IZAWA,Eiji: "K-Ar ages and the initial Ar isotope ratio of aduralia-quartz veins from the Hishikori gold deposit,Japan" Resource Geology Special Issue. No.14. 63-69 (1993)

    • Related Report
      1994 Annual Research Report
  • [Publications] IZAWA,Eiji: "Mudstones in a hydrothernal eruption crater above the gold-bearing systein of the Yamada deposit at HishiKari,Japan" Resource Geology Special Issue. No.14. 85-92 (1993)

    • Related Report
      1994 Annual Research Report
  • [Publications] WATANABE,Koichiro: "Fission track ager of Plio Pleistocene volcanic rocks in the Okuchi region,southern kyushu,Japan" Geotherinal Res.Rep.Kyushu Univ.No.3. 98-110 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 松尾,哲也: "大分県野矢-滝上地域の熱水変質帯" 九大地熱研究報告. 第3号. 111-122 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] 江原,幸雄: "冷却するマグマ直上に発達するマグマ性高温地熱系-九重火山におけるケーススタディー" 地質学論集. 第43号. 169-177 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] IZAWA,Eiji: "K-Ar ages and the initial Ar isotopic ratio of adularia-guarts veins from the Hishikari gold deposit,Japan" Resource Geology Special Issue,No.14. 63-69 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] 清浦 隆: "大分県水分地域の古地熱系について" 九大地熱研究報告. 1号. 10-16 (1992)

    • Related Report
      1992 Annual Research Report

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Published: 1992-04-01   Modified: 2016-04-21  

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