Geophysical imaging reveals topographic stress control of bedrock weathering

TLDR

Bedrock weathering is driven by fractures that break rock into soil, but soil formation hampers direct observation of these processes. The authors combined a 3‑D stress model with seismic reflection and electromagnetic profiling to map bedrock fracture density and demonstrate that erosion rates track topographic changes. The resulting profiles reveal that fracture density follows surface elevation, offering a new method to investigate the critical zone between bedrock and soil. St.

Abstract

Bedrock weathering runs to the hills Fractures in bedrock drive the breakdown of rock into soil. Soil makes observations of bedrock processes challenging. St. Clair et al. combined a three-dimensional stress model with geophysical measurements to show that bedrock erosion rates mirror changes in topography (see the Perspective by Anderson). Seismic reflection and electromagnetic profiles allowed mapping of the bedrock fracture density. The profiles mirror changes in surface elevation and thus provide a way to study the critical zone between rock and soil. Science , this issue p. 534 ; see also p. 506