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Abstract River terraces are commonly used to infer climate and tectonic histories. Yet, it is increasingly recognised that other processes, such as river capture, can affect river terrace genesis and incision rates and patterns. In this study, we conduct a field‐based investigation of river terrace sequences along the Kolokithas and Varitis Rivers in central Crete, Greece, that share a confluence and preserve geomorphic evidence for the recent capture of the Kolokithas headwaters by the Varitis. We use digital topographic analysis, mapping, and optically stimulated luminescence (OSL) geochronology to quantify the river terrace and bedrock incision response to river capture. Topographic analysis indicates the Varitis captured ~30 km²of drainage area from the Kolokithas. We find differences in terrace characteristics, number of terraces, and incision rates and patterns on the adjacent valleys. The Kolokithas has four terrace levels, and the Varitis has five. All terraces are strath terraces, except for the oldest on the Kolokithas, a ~8 m thick fill terrace that starkly contrasts the time‐equivalent ~1–2 m thick strath terrace on the Varitis. Relative and absolute age control suggests three Pleistocene terraces were emplaced during cooler climate intervals, and two Holocene terraces are perhaps because of anthropogenic disturbances. The incision patterns differ on each valley, with generally more incision upstream on the Varitis relative to the Kolokithas. Incision rates on the Varitis are roughly twice as high as on the Kolokithas, but the average incision rate of both valleys combined is comparable to coastal rock uplift rates derived from marine terraces. Collectively, our results suggest that fluvial systems are sensitive to climate and tectonic processes even when affected by geomorphic disturbances, like river capture and beheading. However, care must be taken when interpreting river terraces as direct records of climate and tectonic processes, particularly when working on a single river valley. 

Abstract Bedrock river width is an essential geometric parameter relevant to understanding flood hazards and gauging station rating curves, and is critical to stream power incision models and many other landscape evolution models. Obtaining bedrock river width measurements, however, typically requires extensive field campaigns that take place in rugged and steep topography where river access is often physically challenging. Although prior work has turned to measuring channel width from satellite imagery, these data present a snapshot in time, are typically limited to rivers ≥ 10–30 m wide due to the image resolution, and are physically restricted to areas devoid of vegetation. For these reasons, we are generally data limited, and the factors impacting bedrock channel width remain poorly understood. Due to these limitations, researchers often turn to assumptions of width‐scaling relationships with drainage area or discharge to estimate bedrock channel width. Here we present a new method of obtaining bedrock channel width at a desired river discharge through the incorporation of a high‐resolution bare‐earth digital elevation model (DEM) using MATLAB Topotoolbox and the HEC‐RAS river analysis system. We validate this method by comparing modeled results to US Geological Survey (USGS) field measurements at existing gauging stations, as well as field channel measurements. We show that this method can capture general characteristics of discharge rating curves and predict field‐measured channel widths within uncertainty. As high‐resolution DEMs become more available across the United States through the USGS three‐dimensional elevation program (3DEP), the future utility of this method is notable. Through developing and validating a streamlined, open‐source, and freely available workflow of channel width extraction, we hope this method can be applied to future research to improve the quantity of channel width measurements and improve our understanding of bedrock channels. 

Few natural examples exist where climate’s influence on tectonics is clear. Based on a study of the Sangre de Cristo Mountains in southern Colorado, we argue that climate-driven changes in ice loads affected spatial and temporal slip patterns on the range-front normal fault. Relict glacial features enable the reconstruction of paleoglacier extents and show variable amounts of footwall ice coverage during the Last Glacial Maximum (LGM). Line load models indicate post-LGM ice melting reduced fault clamping stress by ~20–55 kPa at seismic depths. Flexural isostatic modeling shows several meters of footwall uplift due to ice unloading with spatial patterns and magnitudes consistent with post-LGM fault throw measured from offset Holocene and late Pleistocene alluvial fans. Post-LGM fault throw rates are at least a factor of five higher than middle and early Pleistocene rates. We infer that climate-modulated ice-load changes can pace fault clamping stress and slip patterns on range-bounding normal faults. 

Abstract. Carbonate rocks are highly reactive and can have higher ratios of chemical weathering to total denudation relative to most other rock types. Their chemical reactivity affects the first-order morphology of carbonate-dominated landscapes and their climate sensitivity to weathering.However, there have been few efforts to quantify the partitioning ofdenudation into mechanical erosion and chemical weathering in carbonatelandscapes such that their sensitivity to changing climatic and tectonicconditions remains elusive. Here, we compile bedrock and catchment-averagedcosmogenic calcite–36Cl denudation rates and compare them to weathering rates derived from stream water chemistry from the same regions. Local bedrock denudation and weathering rates are comparable, ∼20–40 mm ka−1, whereas catchment-averaged denudation rates are ∼2.7 times higher. The discrepancy between bedrock and catchment-averaged denudation is 5 times lower compared to silicate-rich rocks, illustrating that elevated weathering rates make denudation more spatially uniform in carbonate-dominated landscapes. Catchment-averaged denudation rates correlate well with topographic relief and hillslope gradients, and moderate correlations with runoff can be explained by concurrent increases in weathering rates. Comparing denudation rates with weathering rates shows that mechanical erosion processes contribute ∼50 % of denudation in southern France and ∼70 % in Greece and Israel. Our results indicate that the partitioning between largely slope-independent chemical weathering and slope-dependent mechanical erosion varies based on climate and tectonics and impacts the landscape morphology. This leads us to propose a conceptual model whereby in humid, slowly uplifting regions, carbonates are associated with low-lying, flat topography because slope-independent chemical weathering dominates denudation. In contrast, in arid climates with rapid rock uplift rates, carbonate rocks form steep mountains that facilitate rapid, slope-dependent mechanical erosion required to compensate for inefficient chemical weathering and runoff loss to groundwater systems. This result suggests that carbonates represent an end member for interactions between climate, tectonics, and lithology. 

Abstract. The width of valleys and channels affects the hydrology, ecology,and geomorphic functionality of drainage networks. In many studies, thewidth of valleys and/or channels (W) is estimated as a power-law function ofthe drainage area (A), W=kcAd. However, in fluvial systemsthat experience drainage reorganization, abrupt changes in drainage areadistribution can result in valley or channel widths that are disproportionalto their drainage areas. Such disproportionality may be more distinguishedin valleys than in channels due to a longer adjustment timescale forvalleys. Therefore, the valley width–area scaling in reorganized drainagesis expected to deviate from that of drainages that did not experiencereorganization. To explore the effect of reorganization on valley width–drainage areascaling, we studied 12 valley sections in the Negev desert, Israel,categorized into undisturbed, beheaded, and reversed valleys. We found thatthe values of the drainage area exponents, d, are lower in the beheadedvalleys relative to undisturbed valleys but remain positive. Reversedvalleys, in contrast, are characterized by negative d exponents, indicatingvalley narrowing with increasing drainage area. In the reversed category, wealso explored the independent effect of channel slope (S) through theequation W=kbAbSc, which yieldednegative and overall similar values for b and c. A detailed study in one reversed valley section shows that the valleynarrows downstream, whereas the channel widens, suggesting that, ashypothesized, the channel width adjusts faster to post-reorganizationdrainage area distribution. The adjusted narrow channel dictates the widthof formative flows in the reversed valley, which contrasts with the meaningfullywider formative flows of the beheaded valley across the divide. Thisdifference results in a step change in the unit stream power between thereversed and beheaded channels, potentially leading to a “width feedback”that promotes ongoing divide migration and reorganization. Our findings demonstrate that valley width–area scaling is a potential toolfor identifying landscapes influenced by drainage reorganization. Accountingfor reorganization-specific scaling can improve estimations of erosion ratedistributions in reorganized landscapes.