まとめ
グリーンランドの氷床は3万年前までに現在の限界を超えて100km以上進んだ. 高北極におけるウィスコンシン氷の限られた範囲は,ローレンティド氷床による極端な乾燥状態を示唆している.
科学分野:
- 氷河学 氷河学とは
- 四次地質学 四次地質学
- 北極の古気候学
背景:
- エレスメール島でのフィールド観測は,過去の氷床の動態についての洞察を提供します.
- 氷床の振る舞いを理解することは,将来の気候変動の影響を予測するために不可欠です.
研究 の 目的:
- 北西グリーンランドの氷床とエルスミア島の氷河の歴史を再構築する.
- 氷の前進と後退のタイミングと範囲を決定する.
- 高北極の氷床の行動に影響を与える環境条件を調査する.
主な方法:
- エルスミア島の北東部のフィールド観測と地質地図作成.
- 放射性炭素年代測定法による年代測定は,年代的枠組みを確立するために用いられる (現在より数年前).
- 氷床の縁の分析と氷期後の地形の証拠.
主要な成果:
- グリーンランドの北西の氷床は,現在の限界を超えて100km以上進んだ.
- この大きな進出は,最も外側のエルスミア島の氷の進出 (>B.P.の30,000年) を先行した. ) を実施する.
- 景気後退は,B.P. 28,000〜30,000年の間に始まった. (おそらくB.P.の3万5千年以上前) ),ウィスコンシン州後半の氷の範囲が限られており,氷のない廊下がある.
結論:
- 氷河期の間にも,氷のない地域が大幅に存在していた.
- 高北極におけるウィスコンシン氷の遅期の限られた範囲は,極端な乾燥によって引き起こされた可能性が高い.
- 乾燥は,南のローレンティド氷床の蓄積の結果でした.
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