When the water freezes it expands and the cracks are opened a little wider. Over time pieces of rock can split off a rock face and big boulders are broken into smaller rocks and gravel.
Chemical weathering decomposes or decays rocks and minerals. An example of chemical weathering is water dissolving limestone. When ice melts or wind and water slow down they can't carry as much sediment. The sediment is dropped, or deposited, in landforms. To be the provider of geoscience data globally Navigation Main content Bottom links. Minerals that are rich in iron break down as the iron oxidizes and forms new compounds.
Iron oxide produces the red color in soils. Now that you know what chemical weathering is, can you think of some other ways chemical weathering might occur? Chemical weathering can also be contributed to by plants and animals. As plant roots take in soluble ions as nutrients, certain elements are exchanged.
Plant roots and bacterial decay use carbon dioxide in the process of respiration. Weathering rates depend on several factors.
These include the composition of the rock and the minerals it contains as well as the climate of a region. Figure 9. Different rock types weather at different rates. Certain types of rock are very resistant to weathering.
Igneous rocks, especially intrusive igneous rocks such as granite, weather slowly because it is hard for water to penetrate them. Other types of rock, such as limestone, are easily weathered because they dissolve in weak acids.
Rocks that resist weathering remain at the surface and form ridges or hills. As the surrounding less resistant rocks were worn away, the resistant center of the volcano remained behind. Different minerals also weather at different rates.
Some minerals in a rock might completely dissolve in water but the more resistant minerals remain. When a less resistant mineral dissolves, more resistant mineral grains are released from the rock. Climate is determined by the temperature of a region plus the amount of precipitation it receives. Climate is weather averaged over a long period of time.
Chemical weathering increases as:. So how do different climates influence weathering? A cold, dry climate will produce the lowest rate of weathering. A warm, wet climate will produce the highest rate of weathering. The warmer a climate is, the more types of vegetation it will have and the greater the rate of biological weathering figure This happens because plants and bacteria grow and multiply faster in warmer temperatures.
Some resources are concentrated by weathering processes. In tropical climates, intense chemical weathering carries away all soluble minerals, leaving behind just the least soluble components.
The aluminum oxide, bauxite, forms this way and is our main source of aluminum ore. Answer the question s below to see how well you understand the topics covered in the previous section. This short quiz does not count toward your grade in the class, and you can retake it an unlimited number of times. Use this quiz to check your understanding and decide whether to 1 study the previous section further or 2 move on to the next section.
Privacy Policy. Skip to main content. Module 4: Weathering and Soil Formation. Search for:. Weathering and Erosion Describe types and processes of weathering and erosion. Identify the ways chemical weathering alters materials on Earth. Identify several influences on weathering. Figure 2. Ice wedging. Figure 6.
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