Evolutionary dynamics of the main-stem longitudinal profiles of ten kongdui basins within Inner Mongolia, China

Abstract

The longitudinal profiles of main streams of ten kongdui basins within Inner Mongolian Autonomous Region of China were characterized in this study by analyzing a series of quantitative indexes that are relevant to tectonic activity and river action, and by establishing a series of multiple regression models. The results reveal that all longitudinal profiles are concave in shape, with a range of concavity between 1.1 and 3.1, increasing from west to east. Data also show that the concavity of the profiles is significantly negatively correlated with profile length, altitude difference, average altitude, drainage area and sediment load of the basins. Analysis reveals that kongdui basins have suffered from moderate-to-weak tectonic activity over time, again characterized by a west-to-east weakening trend. Stream power also varies along the main channels of the ten kongdui basins; average values in each case fall between 0.8 W/m and 8.4 W/m, generally higher within the middle reaches. This decreasing trend in stream power within the lower reaches of kongdui basins might provide one key explanation for sedimentation there. Data also show that the average stream power in western and central basins tends to be higher than that in eastern examples, even though both the highest and the lowest values are seen within two middle ones. This analysis shows that the longitudinal profile concavity values are mainly controlled by tectonic activity and that the effect of river action is insignificant.

Assessment of relative tectonic activity using morphotectonic analysis in the Central High Atlas, Demnate Region, Morocco

“…High Bs values indicate elongated and tectonically active basins. On the other hand, Bs values close to 1 indicate a circular basin, weakly influenced by tectonic activity, if at all (Bull and McFadden 1977;Gao et al 2016;Gu et al 2019). According to El Hamdouni et al (2008) and Gentana et al (2018), the BS>4 indicate a high tectonic activity (class 1), 3>BS>4 moderate tectonic activity (class 2), and Bs<3 low tectonic activity (class 3).…”