Waterfalls, river profiles, and the potential to obscure geologic history

Deciphering the interplay between climate, tectonics and surface processes is a fundamental goal of the Earth sciences. In mountainous areas, the shape of river longitudinal profiles can be used to interpret past environmental forcing, and steepened river reaches, or knickpoints, are commonly interpreted to reflect past climatic or tectonic-induced changes in river base level.  However, there exists a growing body of evidence suggesting that knickpoints may form via internal feedbacks that generate bedrock steps and waterfalls in the absence of perturbations in external forcing. If such self-formed knickpoints are widespread, their existence would complicate our ability to interpret geologic history recorded in river profiles.  In this talk, I will explore the mechanisms by which knickpoints can self form, and show ongoing work on how to distinguish knickpoints created via internal feedbacks versus external forcing.

Host: Claire Masteller