Fluvial morphology is affected by a wide range of forcing factors, which can be external, such as faulting and changes in climate, or internal, such as variations in rock hardness or degree of fracturing. It is a challenge to separate internal and external forcing factors when they are co-located or occur coevally. Failure to account for both factors leads to potential misinterpretations. For example, steepening of channel network due to lithologic contrasts could be misinterpreted to be a function of increased tectonic displacements. These misinterpretations are enhanced over large areas, where landscape properties needed to calculate channel steepness (e.g., channel concavity) can vary significantly in space. In this study, we investigate relative channel steepness over the Eastern Carpathians, where it has been proposed that active rock uplift in the Southeastern Carpathians (SEC) gives way N- and NW-wards to ca. 8 Myrs of post-orogenic quiescence. We develop a technique to quantify relative channel steepness, the relative steepness index, based on a wide range of concavities, and show that the main signal shows an increase in relative steepness index from east to west across the range. Rock hardness measurements and geological studies suggest this difference is driven by lithology. When we isolate channel steepness by lithology to test for ongoing rock uplift along the range, we find steeper channels in the south of the study area compared to the same units in the North. This supports interpretations from longer timescale geological data that active rock uplift is fastest in the southern SEC.

中文翻译：

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分离河流剖面的岩性与构造信号以测试东部和东南喀尔巴阡山脉的造山模型

河流形态受多种强迫因素的影响，这些因素可以是外部的，例如断层和气候变化，也可以是内部的，例如岩石硬度或破裂程度的变化。当内部和外部强迫因素位于同一地点或同时发生时，将它们分开是一个挑战。未能考虑到这两个因素会导致潜在的误解。例如，由于岩性对比导致的河道网络陡峭可能被误解为构造位移增加的函数。这些误解在大面积区域得到加强，其中计算渠道陡度（例如渠道凹度）所需的景观特性可能在空间上有显着差异。在这项研究中，我们调查了东喀尔巴阡山脉的相对河道陡度，在那里有人提出东南喀尔巴阡山脉（SEC）的活动岩石隆起让位于 N 和 NW 病房约。造山后静止的 8 迈尔斯。我们开发了一种技术来量化相对通道陡度，即基于各种凹度的相对陡度指数，并表明主要信号显示整个范围内从东到西的相对陡度指数增加。岩石硬度测量和地质研究表明，这种差异是由岩性造成的。当我们通过岩性隔离水道陡度以测试沿该范围持续的岩石隆起时，我们发现研究区南部的水道比北部的相同单元更陡峭。这支持来自更长时间尺度地质数据的解释，即活动岩隆起在南部 SEC 最快。