炭素同位体の証拠は,プロテロゾーイク期の環境の段階的な酸化を示しています

D J Des Marais¹, H Strauss, R E Summons

¹NASA, Ames Research Center, Moffett Field, California 94035.

Nature

|October 15, 1992

まとめ

初期の地球初期の地球

科学分野:

地質化学地質化学
古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
堆積地質学的地質学堆積地質学的地質学

背景:

大気中の酸素化と地殻の酸化は,初期の地球の歴史における重要な出来事である.
堆積岩における炭素の蓄積の減少は,これらの酸化現象と関連していると仮定されています.
炭素循環の理解は,初期の地球環境を再構築するために重要です.

研究の目的:

プロテロゾーイク時代の炭素貯蔵庫と環境酸化との関係を調査する.
堆積物有機炭素と炭酸同位体組成の動向を分析する.
炭素貯蔵庫の変化と,裂け目やオロゲニーなどの主要な地質学的現象を相関させるため.

主な方法:

堆積した有機炭素における炭素同位体組成の分析.
堆積炭酸における炭素同位体組成の分析.
地質学的な出来事の相関 (地球規模の裂け目とオロゲニー).

主要な成果:

プロテロゾーイクエオン (2.5-0.54 Gyr ago) は,炭酸塩貯蔵庫と比較して有機炭素貯蔵庫の大きさが大幅に増加した.
この有機炭素の増加は,環境への酸化力の放出と一致した.
有機炭素貯蔵庫の膨張は,主に地球規模の裂け目とオロゲーニーの期間中に起こった.

結論:

堆積岩における還元炭素の蓄積は,地殻と大気の酸化に重要な役割を果たした.
グローバル・リフティングやオロゲニーなどの地質学的現象は,有機炭素貯蔵庫の拡大の主要な原動力であった.
プロテロゾイク期の炭素循環のダイナミクスは,地球の酸化還元条件の進化に直接影響した.

キーワード:

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