Murton Julian B, Peterson Rorik, Ozouf Jean-Claude
Department of Geography, University of Sussex, Brighton BN1 9QJ, UK.
Science. 2006 Nov 17;314(5802):1127-9. doi: 10.1126/science.1132127.
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.
人们普遍认为，冻结孔隙水的体积膨胀是寒冷潮湿地区岩石破裂的主要原因。模拟自然冻结状态的实验数据表明，基岩破裂实际上是由冰分凝作用导致的。通过将热量和质量传递与裂缝模型耦合，还对裂缝深度和时间进行了数值模拟。裂缝的深度和几何形状与北极永久冻土和冰期风化剖面中的情况相符。这一一致性支持了一个概念模型，即近地表永久冻土中的冰分凝作用逐渐导致岩石破裂和隆起，而永久冻土的退化则偶尔导致分凝冰的融化和岩石沉降。
