ヘリウム同位体比とテクトニクス (1987年度日本地球化学会奨励賞受賞記念)

• 佐野 有司

  東京大学理学部付属地殻化学実験施設

書誌事項

タイトル別名

• Helium isotope ratios and techtonics
• ヘリウム ドウイタイヒ ト テクトニクス 1987ネンド ニホン チキュウ カ

抄録

Recent achievements on helium isotope study are reviewed in the paper. Helium-3 is a unique nuclide which indicates a primordial signature, while most of helium-4 is produced by the radioactive decay of U and Th in crustal rocks. The ³He/⁴He ratios provide useful information on the origin of terrestrial gas and rock samples. It is confirmed that there is a close correlation between the ³He/⁴He ratio of gas and rock samples and the geotectonic structure of the sampling sites. The ³He/⁴He ratio in mid-ocean ridge basalts (MORB) as well as in thermal fluids emitting from a ridge crest is very uniform with the value of 1.2×10^-5 for samples collected at global spreading centers. The MORB type helium is considered to be representative of the Earth's upper mantle. Volcanic gases and rocks from hot spot regions such as Iceland and Hawaii indicate higher ³He/⁴He ratios than that of MORB, suggesting their deeper origin. Geographical distributions of helium isotope ratios in Japan and New Zealand show a quite similar trend: low ³He/⁴He ratio in the frontal arc region and high in the volcanic arc. The mantle helium in the volcanic arc region may be associated with the diapiric uprise of a magma. The low ³He/⁴He ratio in the frontal arc may be attributed to the accumulation of radiogenic helium in crustal rocks.

収録刊行物

• 地球化学

  地球化学 22 (1), 1-11, 1988

  一般社団法人日本地球化学会

詳細情報

• CRID: 1390282680719732992
• NII論文ID: 110008679805
• NII書誌ID: AN00141280
• DOI: 10.14934/chikyukagaku.22.1
• ISSN: 21885923
• ISSN: 03864073
• NDL書誌ID: 3191453
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I3191453
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可