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Science 17 November 2006:
Vol. 314. no. 5802, pp. 1127 - 1129
DOI: 10.1126/science.1132127
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Reports

Bedrock Fracture by Ice Segregation in Cold Regions

Julian B. Murton,1* Rorik Peterson,2 Jean-Claude Ozouf3

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.

1 Department of Geography, University of Sussex, Brighton BN1 9QJ, UK.
2 Department of Mechanical Engineering, University of Alaska, Fairbanks, AK 99775, USA.
3 Laboratoire Morphodynamique Continentale et Côtiere, UMR 6143 CNRS/Université de Caen, 14032 Caen Cedex, France.

* To whom correspondence should be addressed. E-mail: j.b.murton{at}sussex.ac.uk

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Science. ISSN 0036-8075 (print), 1095-9203 (online)