ブラックシェールにおける有機炭素の鉱物表面制御
Martin J Kennedy1, David R Pevear, Ronald J Hill
1Department of Earth Science, University of California, Riverside, CA 92521, USA. martink@mail.ucr
Science (New York, N.Y.)
|January 26, 2002
まとめ
鉱物の表面積は,白期の黒いシェールにおける有機炭素の総変動の85%を説明する. これは,有機炭素の保存における粘土鉱物吸収の重要な役割を強調し,海洋要因よりも大陸の気象が埋葬に影響することを示唆しています.
科学分野:
- 地質化学 地質化学
- 堆積物学 堆積物学 堆積物学 堆積物学 堆積物学
- パレオセアノグラフィー
背景:
- 海洋堆積物における有機炭素の保存は,世界の炭素循環を理解するために極めて重要です.
- ブラックシェイルは,古代の有機炭素の重要な貯蔵庫であり,過去の環境についての洞察を提供します.
- 古代の海洋環境における有機炭素埋葬を制御する要因は,依然として重要な研究分野です.
研究 の 目的:
- 鉱物の表面積と,黒いシェール鉱床における有機炭素の総含有量との関係を調査する.
- 有機物の吸収と保存における鉱物表面,特に粘土鉱物の役割を決定する.
- 石油に弱いシェール層における有機炭素結合機構を理解するために,これらの発見の意味を探求する.
主な方法:
- 西部内陸海路の2箇所から採取したブラックシェールサンプルを分析した.
- 総有機炭素含有量の定量化.
- 鉱物の表面積の測定,粘土鉱物の貢献に焦点を当てた.
- 有機物質と鉱物の関連性を特定するための顕微鏡および光譜分析.
主要な成果:
- 鉱物の表面積が,総有機炭素の変動の85%を説明しているとの強い相関が発見されました.
- 粘土鉱物表面に炭素化合物の吸収が有機炭素保存の主要なメカニズムであることを示す証拠があります.
- 粘土鉱物との密接な関連を示す,スムクタイトの中間層内で有機物質が観察されました.
結論:
- 粘土鉱物学によって導かれる鉱物表面積は,このブラック・シェイルの有機炭素含有量の支配的なコントロールである.
- 鉱物表面への吸収は,現代の海洋堆積物と同様に,有機炭素の埋葬と保存において根本的な役割を果たします.
- 大陸の気象パターンと,その結果生じる粘土鉱物学は,海洋水の化学や,油性シェールにおける有機炭素の蓄積の生産性よりも,より重要かもしれません.
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