古代の,高度に異質なマントルは,北極海のガッケル山脈の下にある
Chuan-Zhou Liu1, Jonathan E Snow, Eric Hellebrand
1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China. chzliu@mail.iggcas.ac.cn
Nature
|March 21, 2008
まとめ
地球の耐火領域は,地球における耐火領域である.
科学分野:
- 地質化学 地質化学
- 海洋学 海洋学とは
- ペトロロジー・ペトロロジーとは
背景:
- 海洋のマントルは,コンベクションによって枯渇し,均質化されていると推定される.
- 濃縮された部分は,この均質性に挑戦します.
- アビッサル・ペリドータイトは,マントルのプロセスについての洞察を提供します.
研究 の 目的:
- 海洋の山脊の下にあるアステノスフィアのマントルの異質性を調査する.
- 耐火性マントルの領域の保存機構を決定する.
- 海洋マントルのオスミウムモデル年齢の解釈を再評価する.
主な方法:
- ガッケル山脈からの耐火性アビスアル・ペリドータイトの分析.
- オスミウムの同位体比 (187Os/188Os) を測定する.
- オスミウムモデル年齢の計算.
主要な成果:
- いくつかのガッケル山脈のペリドータイトは,非常に枯渇した187Os/188Os比率を示しています.
- オスミウムモデルの年齢は,高さ20億年までの耐火領域の保存を示しています.
- これらの古代領域は,海中の玄武岩によって有意なサンプルを採取されていません.
結論:
- 耐火領域はアステノスフィアのマントルに存在し,コンベクションによる均質化に挑戦する.
- 中洋の山脊の下の上流マントルは異質である可能性が高い.
- 海洋マントルのオスミウムモデルの年齢は,大陸の石層の進化について慎重に解釈する必要があります.
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