セノゾイク海水硫酸塩の硫黄同位体組成
1A. Paytan, M. Kastner, and D. Campbell are in the Geosciences Research Division, Scripps Institution of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093, USA. M. H. Thiemens is in the Chemistry Department, University of California, San Dieg.
Science (New York, N.Y.)
|November 20, 1998
まとめ
この研究は,ケノゾイク海水硫酸硫黄同位体曲線を提示し,数百万年にわたる重要なシフトを明らかにしています. 発見は,硫黄と炭素のサイクルがケノゾーイク時代に大気中の酸素を独占していたわけではないことを示唆している.
科学分野:
- 地質化学 地質化学
- パレオセアノグラフィー
- イソトープ地球化学 イソトープ地球化学
背景:
- 紀元期の硫黄循環を理解することは,過去の海洋状態と大気組成を再構築するために重要です.
- 海洋バライトは,海水の硫酸塩同位体組成の貴重なアーカイブとして機能します.
研究 の 目的:
- 亜紀海水硫酸の高解像度硫黄同位体曲線を生成するために.
- 硫黄と炭素循環の関係と大気中の酸素レベルへの影響について調査する.
主な方法:
- 硫黄の同位体組成を決定するために,海洋バリトのサンプルを分析する.
- 生成された硫黄同位体曲線と既存の海洋炭酸炭素同位体記録の比較.
主要な成果:
- 詳細なケノゾイク海水硫酸硫黄イソトープ曲線 (約. 100万年決議) が成立した.
- 曲線は,65~55万年前からの減少,55~45万年前からの急激な増加,35~2万年前からの安定,そして最近の減少を示しています.
- 硫黄と炭素の循環は,何百万年にも及ぶ間,明確な体系的な結びつきは見つかりませんでした.
結論:
- ピライト硫黄と有機炭素の埋葬率の変化は,短期のケノゾイク時代における大気中の酸素を決定しただけではない.
- これらの発見は,大気中の酸素調節とケノゾイク期の気候動態のモデルに影響を与えます.
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