70万年の熱帯アンデス氷河期
D T Rodbell1, R G Hatfield2, M B Abbott3
1Geoscience Department, Union College, Schenectady, NY, USA. rodbelld@union.edu.
Nature
|July 13, 2022
まとめ
アンデス山脈の熱帯の氷河は 70万年以上にわたって 氷の量の変化を 密接に追跡しています 地域的な気候変動は氷河の広がりに影響を及ぼし,半球間の気候のつながりを明らかにした.
科学分野:
- 古代気候学
- 氷河学
- 気候の動態
背景:
- 氷河期のサイクルを理解するには 熱帯氷河期の記録が必要で 記録は稀です
- 氷河活動の半球間比較には,継続的な古気候アーカイブが不可欠です.
- 既存の熱帯記録には,複数の氷河期と氷河期間のサイクルをカバーするために必要な長期的かつ継続的なデータが欠けていることが多い.
研究 の 目的:
- 熱帯氷河期の連続した,独立した古気候アーカイブを確立する.
- 熱帯アンデス氷河の変動と 70万年にわたる地球規模の氷の量との関係を調査する
- 熱帯氷河期に影響を与える 半球間気候の遠隔接続を調査する
主な方法:
- アマゾンの最上部にあるジュニン湖のピストンコアの分析
- 精密な年代表を確立するために 堆積物核の独立年代測定
- 堆積物学と地化学のプロキシを用いて過去の氷河活動の再構築.
主要な成果:
- ジュニン湖の核は,70万年に及ぶ熱帯氷河期を独立して記録した最初の記録です.
- 熱帯アンデスの氷河は,地球規模の氷の量変化を追跡し,明確な10万年周期を示した.
- 氷河の広がりは20万年から40万年前に発生し,水質バランスとモンスーンの変化に関連しています.
- 過去の氷河期の氷河の変動は グリーンランドの温度異常と相関しており,モンスーンによる半球間のつながりを示唆しています.
結論:
- 熱帯の氷河は 氷の量と気候の動態の 信頼できる指標として機能しています
- 地域的な水学とモンスーンの変動は,熱帯の氷河の振る舞いを大きく変化させた.
- 氷河期を通して,熱帯とグリーンランドの氷のコアとの間の持続的な半球間気候のテレコネクションが示唆されています.
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