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Forward and inverse models relating river long profile to monotonic step-changes in tectonic rock uplift rate history: A theoretical perspective under a nonlinear slope-erosion dependency
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  • Yizhou Wang,
  • Liran Goren,
  • Dewen Zheng,
  • Huiping Zhang
Yizhou Wang
Institute of Geology, China Earthquake Administration

Corresponding Author:wangyizhou2016@outlook.com

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Liran Goren
Ben Gurion University of the Negev
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Dewen Zheng
Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou, China.
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Huiping Zhang
State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration
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Abstract

The long profile of rivers is widely considered as a recorded of tectonic uplift rate. Knickpoints form in response to rate changes and faster rates produce steeper channel segments. However, when the exponent relating fluvial incision to river slope, n, is not unity, the links between tectonic rates and channel profile are complicated by channel dynamics that consume and form river segments. Here, we explore non-linear cases leading to channel segment consumption and develop a Lagrangian analytic model for knickpoint migration. We derive a criterion for knickpoint preservation and merging, and develop a forward analytic model that resolves knickpoint and long profile evolution before and after knickpoint merging. We further propose a linear inverse scheme to infer tectonic history from river profiles when all knickpoints are preserved. Our description provides a new framework to explore the links between tectonic uplift rates and river profile evolution when n!=1.