EARTHSC 1G03 Lecture Notes - Frost Heaving, Spheroidal Weathering, Crystallization
21 Mar 2013
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Document Summary
Processes that alter rocks: weathering, erosion and transportation. Weathering: destructive processes that change the physical and chemical character of the rock at or near the surface. Erosion: physical removal of rock particles by an agent such as running water or glaciers. Transportation: movement of eroded particles by agents such as rivers, waves, glaciers, or wind. Mechanical weathering: physical disintegration; break rock into smaller pieces. Chemical weathering: decomposition of rock from exposure to atmospheric agents: proportional to the surface area. Spheroidal weathering: rock has been rounded from initial blocky shape b/c weathering acts quicker and more intense on corners than surface; example of small scale exfoliation . Differential weathering: varying rates of weathering in an area b/c differential resistance among rocks to weathering: ex. When weathered, shale forms gentle slopes of eroded rock debris called talus. Pressure release: reduction of pressure on top of a body of rock; causes rocks at depth to crack as they expand upwards.
