Spatial correlation bias in late-Cenozoic erosion histories derived from thermochronology
Spatial correlation bias in late-Cenozoic erosion histories derived from thermochronology
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DOI：
10.1038/s41586-018-0260-6
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发表时间：
2018-07-05
期刊：
影响因子：
64.8
通讯作者：
Thiede, Rasmus C.
中科院分区：
文献类型：
--
作者：
Schildgen, Taylor F.;van der Beek, Pieter A.;Thiede, Rasmus C.
几十年来，地球表面的侵蚀速率与全球气候变化之间的潜在联系一直引起地球科学家的兴趣（1，2），因为这种耦合对硅酸盐风化（3，4）和有机碳埋藏（5）对气候的影响以及第四纪冰川在景观演变中的作用（1，6）具有影响。根据世界范围的沉积速率，已经提出了全球晚新生代侵蚀速率的增加是对变冷、更多变的气候的响应（7）。然而，其他研究表明，全球侵蚀率可能保持稳定，这表明，所报告的沉积物积累率的增加是由于保存偏差、沉积间断和不同的测量间隔造成的（8-10）。最近，全球汇编的热年代学数据已被用来推断晚新生代时期山区景观的侵蚀速率增加了近两倍（6）。有人认为，这一结果没有影响沉积记录的偏见（11），尽管其他人认为它包含与热年代学数据如何平均（12）和冰川景观中的侵蚀间断（13）有关的偏见。在这里，我们调查了30个在新生代晚期有加速侵蚀报告的地点（6）。我们的分析表明，在23个这样的位置，报告的增加是一个空间相关性偏差的结果，也就是说，结合不同的挖掘历史的数据，从而转换为时间的增加空间侵蚀速率的变化。在四个地点，增加可以解释为构造边界条件的变化。在三种情况下，气候引起的加速度记录，驱动本地化的冰川河谷切割。我们的研究结果表明，热年代学数据目前没有足够的分辨率来评估晚新生代气候变化是否影响全球范围内的侵蚀速率。我们认为，综合当地的研究结果，包括特定位置的信息可能有助于进一步调查全球侵蚀率的驱动因素。
The potential link between erosion rates at the Earth's surface and changes in global climate has intrigued geoscientists for decades(1,2) because such a coupling has implications for the influence of silicate weathering(3,4) and organic-carbon burial(5) on climate and for the role of Quaternary glaciations in landscape evolution(1,6). A global increase in late-Cenozoic erosion rates in response to a cooling, more variable climate has been proposed on the basis of worldwide sedimentation rates(7). Other studies have indicated, however, that global erosion rates may have remained steady, suggesting that the reported increases in sediment-accumulation rates are due to preservation biases, depositional hiatuses and varying measurement intervals(8-10). More recently, a global compilation of thermochronology data has been used to infer a nearly twofold increase in the erosion rate in mountainous landscapes over late-Cenozoic times(6). It has been contended that this result is free of the biases that affect sedimentary records(11), although others have argued that it contains biases related to how thermochronological data are averaged(12) and to erosion hiatuses in glaciated landscapes(13). Here we investigate the 30 locations with reported accelerated erosion during the late Cenozoic(6). Our analysis shows that in 23 of these locations, the reported increases are a result of a spatial correlation bias-that is, combining data with disparate exhumation histories, thereby converting spatial erosion-rate variations into temporal increases. In four locations, the increases can be explained by changes in tectonic boundary conditions. In three cases, climatically induced accelerations are recorded, driven by localized glacial valley incision. Our findings suggest that thermochronology data currently have insufficient resolution to assess whether late-Cenozoic climate change affected erosion rates on a global scale. We suggest that a synthesis of local findings that include location-specific information may help to further investigate drivers of global erosion rates.