オーストラリアのワラウオナ群の初期のアーケーン (約33億~35億年前の) 微生物化石
1Department of Earth and Space Sciences, University of California, Los Angeles 90024, USA.
Science (New York, N.Y.)
|July 3, 1987
まとめ
西オーストラリアで発見された化石微生物は,サイアノバクテリアによる酸素生成 fotosynthesis が 3.3 から 3.5 億年前に存在していたことを示唆しています. これらの古代の化石は,地質学記録で見つかった最も古い化石の1つであり,初期アーケアの生命に関する以前の研究を支持しています.
科学分野:
- パレオバイオロジーの古生物学
- 地質化学 地質化学
- 初期の地球の条件.
背景:
- 初期アーケイアエオン (Early Archean Eon) は地球の歴史における重要な時期であり,初期の生命と代謝過程の出現に関する議論が続いている.
- ワラウォーナ群の微生物化石の以前の発見は,初期の微生物生命の証拠を提供しましたが,その年齢と性質はさらなる根拠が必要です.
研究 の 目的:
- 西オーストラリアの初期アーケイアンチェルトの細胞的に保存された微生物化石を調査し,特徴づけること.
- これらの微生物化石の発見が,光合成と大気中の酸素の初期の進化に及ぼす潜在的な影響を決定する.
主な方法:
- ベッド状の炭酸ケルトの内部にある糸状およびコロニアル化石微生物の顕微鏡検査.
- アペックス・ベースルトとタワーズ・フォーメーションのサンプルを地質学的に分析した.
主要な成果:
- 繊維状やコロニアル形態を含む保存状態の良い化石微生物の発見.
- シアノバクテリアを示唆する細胞タイプの特定.
- 化石を含む層の年代は33億年から35億年前とされています.
結論:
- この発見は,初期アーケーン期にシアノバクテリアと酸素生成光合成が存在した証拠を強く示している.
- これらの微生物化石は,地球上の生命の最も古い地質学的証拠のいくつかを代表し,光合成活動のタイムラインを大幅に後押ししています.
- この発見は,ワラウォーナ群の微生物化石に関する以前の報告を裏付け,生命の初期を研究する上でその重要性を強めている.
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