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ID 57934
フルテキストURL
著者
Feyissa, Dejene Hailemariam The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University
Kitagawa, Hiroshi The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University ORCID
Bizuneh, Tesfaye Demissie The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University
Tanaka, Ryoji The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University ORCID Kaken ID publons researchmap
Kabeto, Kurkura The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University
Nakamura, Eizo The Pheasant Memorial Laboratory for Geochemistry and Cosmochemistry, Institute for Planetary Materials, Okayama University Kaken ID publons researchmap
抄録
New K-Ar ages, major and trace element concentrations, and Sr-Nd-Pb isotope data are presented for Oligocene to recent mafic volcanic rocks from the Ethiopian Plateau, the Main Ethiopian Rift (MER), and the Afar depression. Chronological and geochemical data from this study are combined with previously published datasets to reveal secular variations in magmatism throughout the entire Ethiopian volcanic region. The mafic lavas in these regions show variability in terms of silica-saturation (i.e. alkaline and sub-alkaline series) and extent of differentiation (mafic through intermediate to felsic). The P-T conditions of melting, estimated using the least differentiated basalts, reveal a secular decrease in the mantle potential temperature, from when the flood basalt magmas erupted (up to 1600 degrees C) to the time of the rift-related magmatism (<1500 degrees C). Variations in the Sr-Nd-Pb isotopic compositions of the mafic lavas can account for the involvement of multiple end-member components. The relative contributions of these end-member components vary in space and time owing to changes in the thermal condition of the asthenosphere and the thickness of the lithosphere. The evolution of the Ethiopian rift is caused by a transition from plume-driven to plate-driven mantle upwelling, although the present-day mantle beneath the MER and the Afar depression is still warmer than normal asthenosphere.
キーワード
Ethiopian Plateau
Ethiopian rift
Afar depression
mantle source
mantle melting
発行日
2019-09-12
出版物タイトル
Journal of Petrology
60巻
8号
出版者
Oxford University Press
開始ページ
1681
終了ページ
1715
ISSN
0022-3530
NCID
AA0070444X
資料タイプ
学術雑誌論文
言語
English
OAI-PMH Set
岡山大学
論文のバージョン
author
DOI
Web of Science KeyUT
関連URL
isVersionOf https://doi.org/10.1093/petrology/egz043
ライセンス
https://creativecommons.org/licenses/by-nc-nd/4.0/
助成機関名
文部科学省