美国亚利桑那州立大学Joel S. Leonard的团队在研究安第斯山脉中北部地形和侵蚀的控制中取得新进展。2023年12月12日，国际知名学术期刊《地质学》发表了这一成果。

研究人员通过将新数据与秘鲁和玻利维亚38个已公布的侵蚀率相结合，缩小兼容参数值的范围并解析了非线性、稳健的k_snQ-E关系，表明侵蚀阈值、岩石性质、沉积物特征和径流时间变化的重要影响。相比之下，使用传统的河道坡度指标k _sn，气候和岩性的影响都不明显。研究结果强调，解释空间降雨变化对于理清气候、岩性和山地景观中常见的构造的多重影响至关重要，这是进一步了解这些景观如何演变必要的第一步。

据研究人员介绍，该展示了秘鲁南部极端地形、降雨梯度上取得的17个样品新的¹⁰Be侵蚀率。研究使用归一化通道陡峭度指数的降雨加权变体k_snQ，数据表明，通道陡度值及其地形随降雨量的空间变化而调整。具有相似物理特征的岩石定义了k_snQ与侵蚀率(E)之间的不同关系，表明k_snQ也解决了可蚀性的岩性变化。然而，描述这些关系的参数存在很大的不确定性。

附：英文原文

Title: Controls on topography and erosion of the north-central Andes

Author: Joel S. Leonard, Kelin X. Whipple, Arjun M. Heimsath

Issue&Volume: 2023-12-12

Abstract: We present 17 new ¹⁰Be erosion rates from southern Peru sampled across an extreme orographic rainfall gradient. Using a rainfall-weighted variant of the normalized channel steepness index, k_snQ, we show that channel steepness values, and thus topography, are adjusted to spatially varying rainfall. Rocks with similar physical characteristics define distinct relationships between k_snQ and erosion rate (E), suggesting k_snQ is also resolving lithologic variations in erodibility. However, substantial uncertainty exists in parameters describing these relationships. By combining our new data with 38 published erosion rates from Peru and Bolivia, we collapse the range of compatible parameter values and resolve robust, nonlinear k_snQ-E relationships suggestive of important influences of erosional thresholds, rock properties, sediment characteristics, and temporal runoff variability. In contrast, neither climatic nor lithologic effects are clear using the traditional channel steepness metric, k _sn. Our results highlight that accounting for spatial rainfall variations is essential for disentangling the multiple influences of climate, lithology, and tectonics common in mountain landscapes, which is a necessary first step toward greater understanding of how these landscapes evolve.

DOI: 10.1130/G51618.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G51618.1/630597/Controls-on-topography-and-erosion-of-the-northredirectedFrom=fulltext