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炭酸塩の溶解と,アステノスフィアの電気伝導性
Fabrice Gaillard1, Mohammed Malki, Giada Iacono-Marziano
1Institut National des Sciences de l'Univers (INSU), Université d'Orléans, Université François Rabelais-Tours, Institut des Sciences de la Terre d'Orléans, UMR 6113, 41071 Orléans cedex 2, France. gaillard@cnrs-orleans.fr
Science (New York, N.Y.)
|November 29, 2008
まとめ
シリケート溶液や水ではなく,溶けた炭酸は,地球のマントルの高い電気伝導性を説明します. この発見は,上層マントルの炭素濃度を示唆しており,マントルの伝導性測定で検出できる.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 地質化学 地質化学
- ミネラル物理学 ミネラル物理学
背景:
- 地球のマントルの電気伝導性領域は,通常,シリケート溶融やオリビンの水に起因する.
- マントルの伝導性を理解することは,その構成とプロセスを解釈するために不可欠です.
研究 の 目的:
- 溶けた炭酸塩の電気伝導性を研究するために.
- 溶融炭酸が,アステノスフィアの観測された高い電気伝導性を説明できるかどうかを判断する.
- マントルの伝導性を炭素濃度と結びつけるために.
主な方法:
- 溶けた炭酸塩,溶けたシリケート,および水性オリビンの電気伝導性の実験室測定.
- 実験室データとアステノスフィアの伝導性の地球物理観測の比較.
主要な成果:
- 溶融炭酸は,溶融シリケートよりも3度高い電気伝導性を示しています.
- 溶融炭酸は,水性オリビーンよりも5倍の伝導性がある.
- アステノスフィアの伝導性は,大約0.1%の炭酸塩がペリドートに溶けることで説明できます.
結論:
- アステノスフィアの高い電気伝導性は,炭酸塩溶融の少量の存在を示している可能性が高い.
- マントルの伝導性は,上部マントルの炭素濃度を推定するための新しいプロキシを提供します.
- この発見は,海中の玄武岩で観測された二酸化炭素濃度と一致しています.
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