Chemical Composition of <SUP>18</SUP>O-Depleted Limestone in the Kamioka Zn-Pb Mine

• NAKANO Takanori

  Institute of Geoscience, University of Tsukuba

• MURAKAMI Hiroyasu

  Metal Mining Agency of Japan

• MIYAKE Kazuhiro

  Metal Mining Agency of Japan

• NAKAYAMA Ken

  Metal Mining Agency of Japan

Bibliographic Information

Other Title

• 神岡亜鉛-鉛鉱山産石灰岩の同位体変質に伴う元素組成変化
• Chemical Composition of 18O-Depleted Li
• as a Potential Tool for the Exploration of Skarn Deposits
• スカルン鉱床探査への可能性

Abstract

Limestone in the Sako-nishi area of the Kamioka Zn-Pb mine, central Japan, is depleted in ¹⁸O and ¹³C around the mineralized zone owing to hydrothermal activity in the Cretaceous to Paleogene age. Based on δ¹⁸O values, the Sakonishi limestone was divided into four groups, A (>15‰), B (10-15‰), C (5-10‰), and D (<5‰), and the relationships among the groups were analyzed in terms of their chemical compositions. The concentrations of S, Mg, and Sr in the limestone are independent of its δ¹⁸O value, suggesting that these elements, which mostly substitute for the structural sites in carbonate, did not exchange significantly with the hydrothermal fluid. In contrast, the concentrations of Al, Fe, Mn, P, and Zn tend to increase with decreasing δ¹⁸O value; they are 5 to 15 times more enriched in the highly altered group-D limestone than in the least altered group-A limestone. This enrichment is largely a consequence of the formation of Al-Fe bearing hydrothermal minerals (i.e., chlorite and epidote) and suggests that the isotopically altered limestone was formed by the exchange of C and O with the pervasive hydrothermal fluid, accompanied with the crystallization of Al-Fe minerals through a possible reaction with the host limestone. The elemental composition of limestone may serve as a potential tool for the exploration of skarn deposits. In the Kamioka mine, the Al content (ca. 0.1%), Mg/(Mg+Fe+Mn) (ca. 0.35 by weight), Al/Mg (ca. 0.5), and Al/Sr (ca. 2.0) can be used as indicators for determining the altered limestone and for focusing mineralized zones.

Journal

• Shigen-Chishitsu

  Shigen-Chishitsu 47 (3), 109-119, 1997

  The Society of Resource Geology

Keywords

• Kamioka mine
• Skarn deposit
• Limestone
• Isotopic alteration
• Geochemical indicator
• Mineral exploration

Details

• CRID: 1390282679447477376
• NII Article ID: 130003645423
• NII Article ID: 10002859511
• NII Book ID: AN10379890
• DOI: 10.11456/shigenchishitsu1992.47.109
• ISSN: 21854033
• ISSN: 09182454
• NDL BIB ID: 4274681
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4274681
• Data Source:
  • JaLC
  • NDL
  • CiNii Articles
• Abstract License Flag: Disallowed