The Longitudinal Profiles of the Ten Rivers in North Tianhan Mountains and Their Tectonic Significance

In this paper we carry out a study on the longitudinal profile of the 10 rivers in the north Tianshan Mountains, by fitting the characteristics of the river longitudinal profile using four function patterns, and analyzing the evolution process of the 10 rivers' longitudinal profile based on the stream-power incision model. We reveal the relationships between the evolution process of the river and the tectonic activity. Our study indicates that the concavity index of the Taxihe River is the greatest one among the 10 rivers, and the concavity indexes of the other rivers become small one by one in turn on both sides, so the concavity indexes of the Urumqi River and the Sikeshuhe River are the least ones comparatively. The evolution phase of the river topographic form is the pre-steady-state topography. Consequent analysis reveals that the upward-convex features of the profiles and slope-area plots can be explained by the elevation of the bedrock profile getting higher and higher and the uplift being beyond the incision around the target area.