単一プラジオクラゼ結晶のセリエ分析から,白亜紀中期における高地磁気強度
J A Tarduno1, R D Cottrell, A V Smirnov
1Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY, 14627, USA. john@earth.rochester.edu
Science (New York, N.Y.)
|March 7, 2001
まとめ
地磁気二極モメントは,白紀の正規極性超時期の3倍強かった. この発見は,低地磁気反転周波数と高磁場強度の間の関連性を支持しています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- パレオマグネティズム (古磁気学) とは
- ジオダイナモ理論とは
背景:
- 数値シミュレーションにより,ジオダイナモの効率は二極強度と低反転周波数と相関していることが示唆されています.
- 既存のパレオ強度データは,反転頻度とパレオ強度との分離を示している.
- クレタセアスの正常極性スーパークロン (CNPS) は,安定した地磁気極性の長期間を表しています.
研究 の 目的:
- CNPS中の古磁気二極 Moment を調査するために.
- 低地磁気反転周波数と高地磁気二極 Moment の間の相関の仮説を検証する.
- 既存のデータとの不一致を解決するために,CNPSから新しいパレオ強度データを提供します.
主な方法:
- ラジマハルトラップの玄武岩 (1億1300万年~1億1600万年) のプラジオクラゼ結晶の分析.
- パレオインテンシティを決定するために56のテリエ-テリエ実験の適用.
- 時間の平均化された古磁気二極 Moment の計算.
主要な成果:
- CNPS中の古磁気二極 Moment は,12.5 +/- 1.4 x 10^22 A/m と決定されました.
- この値は,ケノゾイク・クレタチオ初期・ジュラ紀末期の平均二極分子の3倍以上です.
- ケノゾーイクとメソゾーイクにおける頻繁な地磁気逆転の時期は,下極二極の瞬間によって特徴づけられました.
結論:
- この研究は,低地磁気反転周波数と高地磁気場の強さの間の相関を裏付ける強力な証拠を提供します.
- この発見は,解き放たれた反転頻度とパレオ強度に関する以前の解釈に異議を唱えている.
- ジオダイナモは,安定した極性の長期間中に,より強力な二極場を生成し,より効率的に動作する可能性があります.
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