プレオセンの冷却期におけるアンデス高原東部への切断
Richard O Lease1, Todd A Ehlers
1Department of Geosciences, University of Tübingen, Tübingen, Germany. rlease@usgs.gov
Science (New York, N.Y.)
|August 17, 2013
まとめ
アンデス山脈の峡谷の切断は,単なる構造的上昇ではなく,気候変動によって引き起こされました. 地球温暖化が冷却され,水分輸送が強化され,高原を越えてプレオセンの峡谷形成を引き起こした.
科学分野:
- 地球科学 地球科学 地球科学
- 地質学 地質学 地質学
- 気候学 気候学
背景:
- 峡谷の切断は,しばしば構造面の上昇と関連しています.
- しかし,気候の変化は,峡谷の形成を促すこともできる.
- アンデス高原東部には,主要な変形地帯を横断する深い峡谷が特徴です.
研究 の 目的:
- アンデス高原東部沿いの峡谷切断の要因を調査する.
- 峡谷の発展に及ぼすテクトニックと気候の影響を区別する.
- 地域における地質・気候現象のタイムラインを確立する.
主な方法:
- (U-Th) /Heの熱クロノロジーを利用して,地質学的な出来事を日付付けます.
- 断層と峡谷の切断の間の空間的および時間的な関係を分析しました.
- 地質学的発見と古気候データ,特に海面温度との相関関係.
主要な成果:
- ミオセンの断層からプレオセンの峡谷切断へのシフトが北東の高原の縁に記録されています.
- 広範囲に広がったプレオセンの峡谷切断が観測され,温暖から冷却への地球規模の気候の変化と一致しています.
- プレオセンの後半の冷却の間に高原への水分輸送の強化を特定しました.
結論:
- 気候の変化,特にプレオセンの後半の冷却は,峡谷の切断の主な要因でした.
- 海面温度の変動は水分輸送に影響を与え,峡谷の発展をペースにしました.
- プレオセンの峡谷の切断には,気候と比べて,地質学的な活動がより少ない役割を果たした.
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