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Unformatted text preview: chemical weathering occurs when air and water chemically react with rock to alter its composition and mineral content. 3.) Five processes cause mechanical weathering: pressure-release fracturing, frost wedging, abrasion, organic activity, and thermal expansion and contraction. 4.) A talus is an accumulation of loose, angular rocks at the base of a cliff from which they have been cleared by mass wasting. Water expands by 7 to 8 percent when it freezes. If water accumulates in a crack and then freezes, the ice expands in a process called frost wedging. Ice pushes the rock apart but at the same time cements is together. When the ice melts, rock fragments tumble from a steep cliff. Rocks fell from the cliffs mainly as a result of frost wedging. 5.) The most important processes of chemical weathering are dissolution, hydrolysis, and oxidation....
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- Fall '08