Structural control of bedrock river alignment and morphology in the Fraser Canyon, British Columbia, Canada

Abstract

AbstractMany rivers worldwide follow faults because they exploit bedrock damage that occurs in fault zones. However, there has been no quantitative investigation of how closely rivers follow specific faults within a fault zone. Analysis of the Fraser River in southwestern British Columbia reveals the degree of alignment of individual bedrock‐bound canyon reaches with lineaments of the Fraser River Fault. The alignment of the river at the regional scale is controlled by the Fraser River Fault zone, but individual canyons align with subsidiary faults that are visible in elevation data or predicted by the geometry and kinematics of the main fault. We hypothesize canyon reaches that deviate from faults were shifted by large episodic sediment input, creating epigenetic canyons.