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Weathering and Erosion. Chapter 14 Answers to Questions 1-6, & 8 page 348. Three Agents of Mechanical Weathering. Three agents of mechanical weathering are wind, water, and temperature. How Does Ice Wedging Weather Rocks?.
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Weathering and Erosion Chapter 14 Answers to Questions 1-6, & 8 page 348
Three Agents of Mechanical Weathering • Three agents of mechanical weathering are wind, water, and temperature
How Does Ice Wedging Weather Rocks? • Water seeps into cracks and then freezes and expands, which widens and deepens cracks with each freeze and thaw cycle.
2 Activities of Plants or Animals that Help Weather Rocks or Soil • Plants: their roots grow and expand, physically wedging rocks apart. • Animals: dig & burrow, which exposes new rock to the weathering process.
Mechanical vs. Chemical Weathering • Mechanical: Rock is split or broken into smaller material without changing its composition. (Physical process) • Chemical: Break down of rocks when the rock minerals are changed to different substances. (Chemical reactions take place)
3 Chemical Processes that Weather Rocks • Hydrolysis - chemical reaction with water and other substances (feldspar, hornblende, augite) these combine to form clay. • Oxidation - chemical reaction with oxygen and other substances. (Iron bearing substances) , (red soil in Carolina & Virginia) • Carbonation - Carbon dioxide dissolves in H2O to form carbonic acid. Speeds up the process of hydrolysis. Converts compounds into a carbonate.
Compare Hydrolysis, Carbonation, and Oxidation • Oxidation, hydrolysis and carbonation are all chemical processes that weather rocks. • Water plays a role in both hydrolysis and carbonation and it can speed up oxidation. • Oxidation involves elements combining with oxygen. • Hydrolysis changes the composition of minerals that react with water. • Carbonation occurs when minerals react with carbonic acid.
2 Agents of Weathering that Would be Rare in the Desert • Running water and vegetation • Rainfall is low in the desert areas, so fewer streams & rivers exist to erode valley areas. • Low precipitation also limits plant growth, so fewer plants means fewer roots to break up the soil & less shelter for animals, which in greater numbers also expose soil to weathering.
