• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to project page

1986 Fiscal Year Final Research Report Summary

Mineralogical and petrological studies of the origin of Mg-Fe hydrate-carbonate-hydroxide minerals

Research Project

Project/Area Number 60460057
Research Category

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

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

Principal Investigator

ITO Masahiro  College of General Education, Nagoya University, Professor, 教養部, 助教授 (70023603)

Co-Investigator(Kenkyū-buntansha) HOSHINO Mitsuo  College of General Education, Nagoya University, Lecturer, 教養部, 講師 (40023626)
Project Period (FY) 1985 – 1986
KeywordsPyroaurite / Sjogrenite / Occurrence / Optical properties / DTA / TG / Chemical composition
Research Abstract

Pyroaurite-sjogrenite, one of Fe-Mg hydrate-carbonate-hydroxide minerals exhibits five types of mode of occurrence in serpentinites from Yoshikawa, Aichi Prefecture; (1) vein-type, (2) nodule-type, (3) crusty type, (4) platy type, (5) earthy type. The minerals of type(3) to type(5) contain some amounts of Ni besides Mn and Cr. The optical properties of these minerals are variable because of their chemical characteristics; vein-type minerals are extremely pleochroic with high refractive indices and the others are either weakly pleochroic or not pleochroic, with rather low refractive indices. The optical orientation of coalingite was determined for a euhedral flake.
A rapid reversible dehydration-hydration process is characteristic of this mineral below about 250゜C. An intermediate dehydrated crystalline phase is formed between 110゜ and 140゜C and continue to exist up to 300゜C, gradually contracting the basal spacing. It should be noted, however, that two dehydrated crystalline phases were identified during the thermal decomposition of coalingite which DTA pattern is very similar to that of pyroaurite-sjogrenite.
Pyroaurite-sjogrenite together with coalingite develops directly from brucite in serpentinites in this area. The reaction may take place in the presence of <CO_2> -bearing underground water which was injected into the brucite-serpentinite. <N_1> was derived undoubtedly from olivines in the ultramafic rocks. After the pyroaurite-sjogrenite was formed, the serpentinite body intruded into the country rocks, accompanied by intensely crushing and fracturing. Coalingite may be formed at the ground surface conditions.
Thermal behavior of <H_2O> and <CO_2> in the inter-layer through the dehydration-hydration process should be keenly studied in the near future.

  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] ITO,M.: TMPM Tschermaks Mineralogische und Petrographische Miteilungen. 35. 193-216 (1986)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] HOSHINO,M.: Lithos. 19. 11-25 (1986)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] ITIHARA,Y.;SUWA,K.;HOSHINO,M.: Geochemical Journal. 20. 201-207 (1986)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] ITO, M.: "Kimberlites and their ultramafic xenoliths from western Kenya" TMPM Tschermaks Mineralogische und Petrographische Mitteilungen. 35. 193-216 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] HOSHINO, M.: "Amphiboles and coexisting ferromagnesian silicates in granitic rocks in Mahe, Seychelles" Lithos. 19. 11-25 (1986)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] ITIHARA, Y., SUWA, K. and HOSHINO, M.: "Geochemical studies on organic matter in the Kavirondian sedimentary rocks of Archaean period in Kenya" Geochemical Journal. 20. 201-207 (1986)

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

URL: 

Published: 1988-11-10  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi