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The stability of drainage divides carries important tectonic and climatic information. However, there is still no consensus on the criterion for measuring the stability of drainage divides, which may lead to different conclusions. There are two different views on the stability of the divide at the Wulashan horst, northern margin of the Ordos block: The drainage divide is moving northward, according to the comparison of drainage-basin morphology (such as elbows of capture, knick points); The drainage divide remains stable, according to the comparison of Gilbert metrics. In this study, we used the χ-plot method to check both the stability of the Wulashan drainage divide and the reliability of the above methods. The analysis shows that the χ value at the top of the northern side is higher than that at the same elevation of the southern side if a lower baseline was set (1300 m a.s.l.); If a higher baseline (~1800 m a.s.l.) is set, the χ values on both sides of the divide are the same at the same elevation. Because the tilting has relatively less influence, the χ-plot with a higher baseline is more representative of the drainage divide stability. In summary, the result supports the view that the drainage divide at the Wulashan horst is at a steady state. Moreover, we discussed the limitations of the methods in measuring the stability of drainage divides.

The Chenghai Fault in the Chuan–Dian block terminates at the northwestern segment of the Red River Fault, and is a significant seismogenic structure. The kinematic evolution of this fault should be closely related to the regional tectonic deformation. However, it is difficult to obtain information on structural deformation of the Chenghai Fault due to the large amount of precipitation and well-developed vegetation. The Chenghai normal faulting may drive drainage reorganization in this region, which provides a new perspective for reconstructing and evaluating the tectonic history. High-resolution digital elevation models (DEM) obtained by remote sensing greatly facilitate the study of drainage evolution and active tectonics. We use two methods (χ-plot and Gilbert metrics) to measure the drainage divide stability based on the ALOS DEM (12.5 m resolution) and further reproduce the drainage evolution process in response to the asymmetric uplift by numerical modeling. The results show that the Chenghai–Jinsha drainage divide, hosted by the footwall block of the Chenghai Fault, is migrating westward (away from the Chenghai Fault) and will continue moving ~2.2–3.5 km to reach a steady state. Its migration is controlled by the Chenghai normal faulting. The Chenghai–Jinsha drainage divide formed close to the Chenghai Fault's surface trace and continues to migrate westward in response to the asymmetric uplift. It only took a few million years for the Chenghai–Jinsha drainage divide to migrate to its current location based on the numerical modeling. The restoration of the drainage reorganization implies that the Chenghai Fault initiated in the Pliocene, which probably results from kinematic reversal along the Red River Fault. [ABSTRACT FROM AUTHOR]

The Cenozoic India‐Asia collision has elevated the Tibetan Plateau and produced large strike‐slip faults in the interior and margins of the plateau, which profoundly influenced drainage reorganization and divide migration in Asia. Recent studies have revealed that the drainage divides between the major rivers in and around the Tibetan Plateau have been migrating for tens of millions of years, due to tectonic and/or climatic disturbance or river capture events. Drainage‐divide stability analysis can provide new, independent insights into the Cenozoic evolution of the river systems. In this study, we focus on the Hanzhong Basin and the adjacent Micang Shan (Shan means Mountain(s)) at the tail of the Qingchuan strike‐slip fault in the outskirts of eastern Tibet. We investigated the stability of the Micang Shan drainage divide, which separates the Han and Jialing rivers (two major tributaries of the Yangtze River), using two methods—χ‐plot and Gilbert metrics. The results show that most segments of the Micang Shan drainage divide are either moving south or stable. We further calculated the predicted stable divide location and identified the abandoned river channels and residual planation surfaces. Based on these analyses, we suggest that (1) the migration of the Micang Shan drainage divide is driven by the tectonic subsidence of the Hanzhong Basin; and (2) the upper reaches of the Han River flowed southward to the Sichuan Basin before basin subsidence. This study supports the hypothesis that the Palaeo‐Middle Yangtze River and its tributaries primarily flowed southward. Moreover, the flow direction of the Middle Yangtze River has been, and still is, transitioning from southward to eastward. The change in river network flow direction is driven by regional block tilting towards the east, surface deformation from strike‐slip faulting, regional extension east of the Tibetan Plateau and/or increased influence from the summer monsoon. [ABSTRACT FROM AUTHOR]

The lateral movement of drainage divides is co-influenced by tectonics, lithology, and climate, and therefore archives a wealth of geologic and climatic information. Several methods have been proposed to determine the direction of drainage-divide migration. However, how to quantify the migration rate of drainage divides remains challenging. Here, we propose a new approach to calculate the migration rate of drainage divides from high-resolution topographic data. The new method is based on the cross-divide comparison of channel-head parameters, including the critical upstream drainage area and the gradient of channel head, both of which are used to calculate the normalized channel steepness at the channel head. We then apply the new method to an active rift shoulder (Wutai Shan), and a tectonically stable area (a mountain range in the Loess Plateau) in North China, to illustrate the calculation of drainage-divide migration rates. The northward migration rates at the Wutai Shan range from 0.10 to 0.13 mm/yr. The migration rates are approximately zero at the mountain range in the Loess Plateau. This study demonstrates that the migration rate of drainage divides can be determined more accurately once the cross-divide differences in uplift rate are taken into account. [ABSTRACT FROM AUTHOR]