涼しくなる気候下で,山の侵食が世界的に加速している
Frédéric Herman1, Diane Seward2, Pierre G Valla1
11] Institute of Earth Sciences, University of Lausanne, CH-1015 Lausanne, Switzerland [2] Department of Earth Sciences, Swiss Federal Institute of Technology, Sonneggstrasse 6, CH-8092 Zürich, Switzerland.
Nature
|December 20, 2013
まとめ
世界的な山岳侵食率は,特に200万年前以降,著しく増加しています. 氷河地域で最も顕著なこの上昇は,気候の冷却と氷河が侵食と堆積物の流れを加速させたことを示唆しています.
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
- 気候科学 気候科学
背景:
- 気候は,地球の表面の侵食プロセスに大きく影響を与えます.
- 紀元後期の冷却と北半球氷河期が地球規模の侵食速度に及ぼす影響は十分に理解されていません.
- 課題には,堆積物記録の解釈と,地形構造と気候侵食の貢献を区別することが含まれます.
研究 の 目的:
- グローバルな侵食率とその時間的変動を定量化するために.
- 気候の冷却と氷河化が山の侵食に与える影響を調査する.
- 何百万年にもわたって地球上の堆積物流の変化を評価するためです.
主な方法:
- 世界的に18,000の岩石基層の熱クロノメトリック年代をまとめました.
- 侵食率を推定するために公式の逆転手順の適用.
- 地質学的時間尺度における沈殿源地域の侵食の定量化.
主要な成果:
- 山の侵食率は,約600万年前から増加し,200万年前から最も急速に加速しています.
- 侵食率の上昇は,世界中で観察されていますが,氷河地帯の山脈で最も顕著です.
- 結果は,氷河のプロセスが侵食を促進する上で重要な役割を果たしていることを示しています.
結論:
- 世界的な山岳侵食と堆積物流が増加し,プレオセーヌ・プレイストセーヌの冷却と氷河化に一致しています.
- 氷河過程は,山岳の侵食率の増加の主要な要因である.
- この発見は,気候と地球表面のプロセスとの長期的結合についての洞察を提供します.
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