5.l.1 Physical Weathering(物理风化) Rain Cracks (b) (b)Ice,expanding as it freezes in rock cracks,breaks off pieces of rock,a process known as frost wedging(冰劈作用)
(b)Ice,expanding as it freezes in rock cracks, breaks off pieces of rock, a process known as frost wedging(冰劈作用） 5.1.1 Physical Weathering （物理风化）
5.l.1 Physical Weathering(物理风化) (c)The results of frost wedging(冰劈作用)at high altitudes
(c)The results of frost wedging(冰劈作用)at high altitudes 5.1.1 Physical Weathering （物理风化）
5.l.1 Physical Weathering-exfoliation(层裂) Surface Several kilometers Batholith (a) (a)Batholith(岩基)at depth
5.1.1 Physical Weathering-exfoliation（层裂） (a）Batholith（岩基） at depth
5.l.1 Physical Weathering-exfoliation(层裂) Sheet joints Erosion Erosion Expansion 个◆ ,_Uplift of region、14 (b) (b)Pressure reduction due to erosion of overlying rock layers causes upward expansion in granite and fractures parallel to the ground surface
（b）Pressure reduction due to erosion of overlying rock layers causes upward expansion in granite and fractures parallel to the ground surface 5.1.1 Physical Weathering-exfoliation（层裂）
5.1.1 Physical Weathering-exfoliation ( (e (c)Exfoliation(层裂)at work in the White Mountains of New Hampshire
（c）Exfoliation （层裂 ）at work in the White Mountains of New Hampshire 5.1.1 Physical Weathering-exfoliation（层裂）