ネバダ州デビルズホールの静脈カルシットから,連続した50万年の気候記録
まとめ
ネバダ州デビルズ・ホール (Devils Hole) の古気候記録は,50万年の温度の歴史を明らかにしています. この大陸記録はミランコビッチ仮説に異議を唱え,内部気候システムのフィードバックが氷河周期を駆動することを示唆している.
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:
- 古代気候アーカイブの酸素同位体 (デルタ 18 O) 分析は,過去の気温と氷の量についての洞察を提供します.
- デビルズ・ホール・カルシット・コア (DH-11) は,独特で連続した大陸の古生物学記録を提供している.
研究 の 目的:
- ネバダ州デビルズホールの長期古気温記録を再構築する.
- この大陸記録を,確立された南極と海洋の古気候アーカイブと比較するために.
- プレイストセンの氷河周期の原動力を調査し,ミランコビッチ仮説を検証する.
主な方法:
- 36cmの静脈カルシート核 (DH-11) の酸素同位体 (デルタ(18) O) 分析.
- 21の複製された質量スペクトロメトリックウランシリーズ日付を用いた年代測定.
- デビルズホールの記録とヴォストークの氷芯と海洋デルタの記録の比較.
主要な成果:
- 500万年連続した古気温記録が確立されました.
- この記録は,ボストクの主要な特徴と,海洋氷の量記録と密接に一致しています.
- 氷河期の周期期間は (8万年から13万年) 大きく変化しており,無周期性を示しています.
- 氷河期間の期間は約2万年続いた.
- 脱氷は,主に軌道内照射の変動によって引き起こされたわけではない.
結論:
- 悪魔の穴の古気温記録は,プレイストセンの氷河周期の唯一の原動力としてミランコビッチ仮説に異議を唱える.
- 観測された氷河周期の動態は,地球の気候システム (大気-氷床-海洋) 内の内部非線形フィードバックと一致しています.
- 主要な気候の変化は,単なる外的軌道強制ではなく,複雑なシステム相互作用によって引き起こされ,非周期的であるように思われる.
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