大盆地静脈カルシットからの25万年の気候記録:ミランコビッチ理論への含意
まとめ
大盆地からの大陸の酸素-18 (デルタ(18) Oの変動の継続的な記録は,最後の氷河間段階が以前よりかなり早く始まったことを示唆しています. これは,既存の海洋年代表と,プレイストセンの氷河期における軌道強制の主要な役割に異議を唱えている.
科学分野:
- 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
- 地質化学 地質化学
- 四次地質学 四次地質学
背景:
- プレイストセンの気候ダイナミクスを理解することは,地球の気候の歴史を再構築するために不可欠です.
- 海洋堆積物や氷核からの酸素同位体記録 (デルタ 18 O) は,過去の気候変動に関する重要な洞察を提供します.
- プレイストセンの気候現象,特に海洋酸素同位体第5段階に関する既存の年代表は,間接的な年代測定方法に基づいています.
研究 の 目的:
- プレイストセンの中期から後期にかけての大陸水層の酸素-18変動の連続した,独立した日付の記録を確立する.
- 大陸記録から派生した気候現象のタイミングを,確立された海洋および氷のコア記録と比較するために.
- 既存の海洋酸素同位体クロノロジーに必要とされる潜在的な改訂を調査し,プレイストセンの氷河期のドライバーを再評価する.
主な方法:
- ネバダ州デビルズ・ホールのカルシット静脈のウラン・シリーズ・デッティング (U-Th).
- 大陸の地下水を表すカルシット静脈の酸素-18 (デルタ(18) O) 変動の分析.
- 導出デルタ ((18) Oのタイムシリーズの比較と海洋と南極の氷河核 (Vostok) デルタ ((18) Oの記録.
主要な成果:
- 50万~310万年前 (ka) の南のグレート・ベッシンからの連続的なデルタ記録が生成されました.
- 大陸デルタ ((18) O曲線は,海洋とヴォストークの氷のコア記録との類似点,しかし重要なタイミングの相違を示しています.
- 最後の氷河期間の段階 (海洋酸素同位体第5段階) は,147 +/- 3ka以前に遡るもので,海洋記録が示唆するよりもかなり早く遡る.
結論:
- 大陸の水層記録は,海洋酸素同位体年代表が改訂を必要とする可能性があることを示しています.
- 主要なプレイストセンの気候現象のタイミングは,海洋記録に基づく現在の解釈とは異なる場合があります.
- 軌道強制は,プレイストセンの氷河期の唯一のまたは主要な要因ではないかもしれませんが,他の要因が関与していることを示唆しています.
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