Bedrock Fracture by Ice Segregation in Cold Regions

TLDR

Rock fracture in cold humid regions has long been attributed to the volumetric expansion of freezing pore water. The authors simulate fracture depth and timing by coupling heat and mass transfer with a fracture model. Experiments simulating natural freezing regimes show that bedrock fracture arises from ice segregation, with fracture depth and geometry matching Arctic permafrost and ice‑age weathering profiles, supporting a model where ice segregation in near‑surface permafrost progressively fractures and heaves rock, while permafrost degradation episodically melts segregated ice and causes rock settlement.

Abstract

The volumetric expansion of freezing pore water is widely assumed to be a major cause of rock fracture in cold humid regions. Data from experiments simulating natural freezing regimes indicate that bedrock fracture results instead from ice segregation. Fracture depth and timing are also numerically simulated by coupling heat and mass transfer with a fracture model. The depth and geometry of fractures match those in Arctic permafrost and ice-age weathering profiles. This agreement supports a conceptual model in which ice segregation in near-surface permafrost leads progressively to rock fracture and heave, whereas permafrost degradation leads episodically to melt of segregated ice and rock settlement.