How does an exfoliation dome form? What will be an ideal ...

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How does an exfoliation dome form?
 
  What will be an ideal response?

Question 2

Explain how water can cause mechanical weathering.
 
  What will be an ideal response?

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Answer to Question 1

A large igneous mass formed deep beneath the surface, where confining pressure is great. As erosion removes the overlying bedrock (a process called unloading), the outer parts of the igneous mass expand. Joints form parallel to the surface. Continued weathering causes thin slabs to separate and fall off, creating exfoliation domes.

Answer to Question 2

Water can cause mechanical weathering by freezing in the pore spaces and fractures within rock. When it freezes, it expands, gradually pushing apart the space or fracture, which allows for more water to fill in and freeze and continue the effect. This is called frost wedging. Water is the most important agent of chemical weathering. Oxygen dissolved in water can oxidize (rust) materialsthis is oxidation. Carbon dioxide dissolved in water creates carbonic acid, which readily dissolves some rockthis is dissolution. Further, carbonic acid reacts with some rock and replaces ions, most often potassium ions, with hydrogen ions, transforming rock into claythis is hydrolysis.

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