Worldwide acceleration of mountain erosion under a cooling climate
Worldwide acceleration of mountain erosion under a cooling climate
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DOI：
10.1038/nature12877
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发表时间：
2013-12-19
期刊：
影响因子：
64.8
通讯作者：
Ehlers, Todd A.
中科院分区：
文献类型：
--
作者：
Herman, Frederic;Seward, Diane;Ehlers, Todd A.
气候影响着作用于地球表面的侵蚀过程。然而，晚新生代时期的降温，包括上新世-更新世北半球冰川的开始(大约200万至300万年前)，对全球侵蚀速率的影响仍不清楚(1-4)。不确定性主要是由于在使用沉积记录作为侵蚀的替代物方面缺乏共识(3，4)，以及很难确定构造和气候对侵蚀的各自贡献(5-7)。在这里，我们汇编了来自世界各地的18,000个基岩温度计时年龄，并使用正式的反演程序(8)来估计侵蚀速率的时间和空间变化。这使得可以对最终产生数百万年时间尺度的沉积物记录的源区的侵蚀进行量化。我们发现，自大约600万年前以来，山脉侵蚀率一直在增加，其中最快的是自200万年前以来。在所有纬度都可以观察到侵蚀速率的增加，但在冰川山脉最为明显，这表明冰川过程发挥了重要作用。由于山脉占全球沉积物产量的相当大一部分(9)，我们的结果表明，全球范围内的沉积物通量增加，这与上新世和更新世(10，11)期间的冷却增强密切相关。
Climate influences the erosion processes acting at the Earth's surface. However, the effect of cooling during the Late Cenozoic era, including the onset of Pliocene-Pleistocene Northern Hemisphere glaciation (about two to three million years ago), on global erosion rates remains unclear(1-4). The uncertainty arises mainly from a lack of consensus on the use of the sedimentary record as a proxy for erosion(3,4) and the difficulty of isolating the respective contributions of tectonics and climate to erosion(5-7). Here we compile 18,000 bedrock thermochronometric ages from around the world and use a formal inversion procedure(8) to estimate temporal and spatial variations in erosion rates. This allows for the quantification of erosion for the source areas that ultimately produce the sediment record on a timescale of millions of years. We find that mountain erosion rates have increased since about six million years ago and most rapidly since two million years ago. The increase of erosion rates is observed at all latitudes, but is most pronounced in glaciated mountain ranges, indicating that glacial processes played an important part. Because mountains represent a considerable fraction of the global production of sediments(9), our results imply an increase in sediment flux at a global scale that coincides closely with enhanced cooling during the Pliocene and Pleistocene epochs(10,11).