The controls on precious metals content of massive sulfide deposits

2022 Fiscal Year Research-status Report

• Project/Area Number: 20K05395
• Research Institution: Akita University
• Principal Investigator: AGANGI ANDREA 秋田大学, 国際資源学研究科, 教授 (20840812)
• Co-Investigator(Kenkyū-buntansha): 高橋 亮平 秋田大学, 国際資源学研究科, 准教授 (10396286)
• Project Period (FY): 2020-04-01 – 2025-03-31
• Keywords: Kuroko / Massive sulfide deposit / Metals / Hydrothermal process

Outline of Annual Research Achievements

The research has continued according to plan during financial year 2022.
New samples of volcanic rocks hosting the Kuroko ore have been collected during various short trips to the field in the Hokuroku area, around Oodate, Akita-ken. New analyses have been completed, some at Akita University, and others have been made in external laboratories.
These analyses included chemical analyses of volcanic rocks, collected from the field, and ore samples, deriving from the collection of Akita University. Chemical analyses allow to understand the abundance of metals (including Zn, Pb, Cu and others) in the analysed samples. Mineral analyses of the main minerals have been completed with th instruments available at Akita University. In addition, mineral identification analyses have been completed as part of student projects. A compilation of the results available so far is currently being made. The new results will be be compared with previously published analyses.
A paper on the geology of the Kuroko ore of the Hokuroku area, which reports the results of the study in the last few years, has been published recently in a international journal, as detailed below.
Agangi, Manalo, Takahashi, Veeravinantanakul, Elburg, 2022. Contributions to Mineralogy and Petrology 177, 115.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

An unexpected event in the development of the research is the delay of some lead (Pb) isotope analyses, which are planned to be carried out overseas in a collaborating institution. The laboratory in question was closed for work during 2022, and the return to normal activity has so far been slower than expected. Therefore, the analyses could not be carried out as planned.

Strategy for Future Research Activity

For year 2023, new analyses will be made.
Zircon U-Pb analyses, to be conducted in a collaborating laboratory overseas, will help determining the age of the ore deposits.
Lead isotope analyses of the ore samples will allow to characterise the type of Pb in the samples and compare it with Pb deriving from different possible sources, such as volcanic rocks hosting the ore formed at the same time as the ore deposits, or much more ancient rocks that occur deeper in the crust.
A new paper is currently under preparation, and is expected to be submitted for publication towards the end of the financial year 2023.

Causes of Carryover

Some of the planned analyses were delayed due to work in the collaborating laboratory (University of the Witwatersrand, Johannesburg), which has continued longer than expected. However, normal operation is currently being re-established and the analyses are being rescheduled over the next months. These analyses will require international travel.

Research Products

• [Journal Article] Magmatic evolution and metal systematics of back-arc volcanic rocks of north-east Japan and implications for deposition of massive sulphide Kuroko ores (2022)
  • Author(s): Agangi, A., Manalo, P.C., Takahashi, R., Veeravinantanakul, A., Elburg, M.A.
  • Journal Title: Contributions to Mineralogy and Petrology Volume: 177 Pages: 115
  • DOI: 10.1007/s00410-022-01980-z
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] A multiple sulphur record of super-large volcanic eruptions in Archaean pyrite nodules (2022)
  • Author(s): Agangi, A., Hofmann, A., Eickmann, B., Ossa Ossa, F., Tyler, P., Wing, B., Bekker, A.
  • Journal Title: Earth and Planetary Science Letters Volume: 594 Pages: 117737
  • DOI: 10.1016/j.epsl.2022.117737
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Primary source of placer gold in the Luk Ulo Metamorphic Complex, Central Java, Indonesia (2022)
  • Author(s): Suhendra, R., Takahashi, R., Imai, A., Setiawan, N.I., Agangi, A.
  • Journal Title: Resource Geology Volume: 72 Pages: e12300
  • DOI: 10.1111/rge.12300
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Bi-Ag-sulfosalts and sulfoarsenides in the Ruwai Zn-Pb-Ag Skarn Deposit, Central Borneo, Indonesia (2022)
  • Author(s): Dana, C.D.P., Agangi, A., Idrus, A., Lai, C.-K. Simbolon, Doly R.
  • Journal Title: Minerals Volume: 12 Pages: 1564
  • DOI: 10.3390/min12121564
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Geology, geochemistry, and genesis of gold mineralization in the Chifumbazi deposit of the Tete Province, Irumide Belt, Mozambique (2022)
  • Author(s): Fadlin, Takahashi, R., Agangi, A., Sato, H., Idrus, A., Sutopo, B., Pratiwinda R.
  • Journal Title: Resource Geology Volume: 73 Pages: e12308
  • DOI: 10.1111/rge.12309
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Trace element and S-isotope composition of pyrite from the Witwatersrand Basin, South Africa (2023)
  • Author(s): Andrea Agangi, Axel Hofmann, Giuliana da Costa, Emilie Thomassot
  • Organizer: 5th IGS “Precambrian World 2023”
• [Presentation] Geological and geochemical characterization of the Chifumbazi gold prospect, Irumide belt, Tete province, Northern Mozambique (2022)
  • Author(s): Cossa, E.P.F., Agangi, A., Takahashi, R., Manalo, P., Imai, A., Manjate, V.
  • Organizer: Society of Economic Geology Minerals For Our Future
  • Int'l Joint Research
• [Presentation] Trace elements and U-Pb dating of zircon from the Humpa Leu East porphyry Cu-Au prospect, Sumbawa Island, Indonesia: Implications for petrogenesis and magma fertility assessment (2022)
  • Author(s): Fadlin, Takahashi, R., Agangi, A., Elburg, M.A., Idrus A., Sutopo, B., Pratiwinda R.
  • Organizer: Society of Economic Geologists Conference
  • Int'l Joint Research
• [Presentation] Association of gold and hydrothermal pyrite in the metamorphic-hosted gold mineralization at the Awak Mas deposit and Luk Ulo prospect, Indonesia (2022)
  • Author(s): Suhendra, R., Takahashi, R., Agangi, A., Tuakia, M.Z., Sato, H.
  • Organizer: Japan Geoscience Union Meeting
  • Int'l Joint Research