Geochemistry of Nd and Ce isotopes and REE abundances in Precambrian orthogneiss clasts from the Kamiaso conglomerate, central Japan.

• Shimizu Hiroshi

  Department of Earth Sciences, Faculty of Science, Kumamoto University

• Lee Seung-Gu

  Korea Institute of Geology

• Masuda Akimasa

  Department of Chemistry, University of Electro-communications

• Adachi Mamoru

  Department of Earth and Planetary Sciences, School of Science, Nagoya University

抄録

Neodymium and cerium isotopic ratios, rare earth clement abundances and major element compositions were determined for Precambrian orthogneiss and granite clasts in the Jurassic Kamiaso conglomerate from central Japan. Three types of REE patterns are observed for the Kamiaso samples: (1) reverse S-shaped patterns with high enrichment of LREE, (2) patterns consisting of upward convex La-Nd span and reverse S-shaped Nd-Lu span, and (3) patterns consisting of two or three rectilinear lines with an inflection at Ho (and Nd). Sm-Nd data on these rocks give an age of 2.07 ± 0.06 Ga (2σ) with ε_Nd (2.07 Ga) = –1.9 ± 0.4. The Sm-Nd age is in accordance with the Rb-Sr whole-rock age of 2.05 Ga for quartzo-feldsparthic gneiss clasts by Shibata and Adachi (1974), confirming that the age of ca. 2.05 Ga indicates the time of formation of the original granitic rocks. The initial value of ε_Nd (2.07 Ga) = –1.9 shows slightly enriched or chondritic feature for the source of original granitic rocks at 2.07 Ga. This study shows that Precambrian episodes and protolithic features can be understood from Precambrian orthogneiss and granite clasts in Mesozoic conglomerates, since the clasts have not undergone post-depositional thermo-tectonic influences.

収録刊行物

• ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ

  ＧＥＯＣＨＥＭＩＣＡＬ　ＪＯＵＲＮＡＬ 30 (1), 57-69, 1996

  一般社団法人日本地球化学会

キーワード

• Geochemistry and Petrology
• Geophysics

詳細情報

• CRID: 1390001204550867584
• NII論文ID: 10008800561
• NII書誌ID: AA00654975
• DOI: 10.2343/geochemj.30.57
• COI: 1:CAS:528:DyaK28XjsVWmur4%3D
• ISSN: 18805973
• ISSN: 00167002
• ISSN: http://id.crossref.org/issn/00167002
• Web Site: http://www.jstage.jst.go.jp/article/geochemj1966/30/1/30_1_57/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可