Weathering definition3/1/2024 Wetting and drying (water-layer weathering) This type of weathering is most effective on high latitude coasts that have significant rainfall. Repeated freezing and thawing will eventually cause the rock to split/disintegrate. When it thaws, the water is released from the crack, leaving behind a bigger crack than before. This water freezes, making the water expand and creating a bigger crack. This is the primary weathering that occurs in coastal areas. The heat expands the crystals, exerting enormous pressure on the rock, causing it to disintegrate. Saltwater collects in cracks in rocks and cliff faces warm (er) temperatures evaporate the water and leave the salt crystals behind. The table below summarises the information mentioned above and the effects on coasts in particular. 4 - The Wash estuary in East Anglia, an example of wetting and drying Mechanical weathering effects on coasts This clay often gets wet and then dries, cracking the clay.įig. This estuary is located on the coast and has a lot of clay. Another name for saltwater crystal growth is haloclasty.Īn example is the Wash, an estuary on the East coast in East Anglia, UK. The crystals put immense pressure on the rock, causing it to break. When the temperatures rise, the crystals heat up and expand. When salty seawater collects in cracks in rocks, crystals form when that salt water evaporates, leaving only the salt particles behind. Let's look at the mechanical weathering processes applicable to coasts in a bit more detail. While there are different types of weathering and weathering processes, considering our primary focus is on coasts, we will be looking at the weathering types that are relevant to coastal landscapes, namely: Mechanical weathering involves disintegration or rocks breaking up into smaller pieces with no chemical composition changes. Rock is broken up or disintegrated because of a variety of physical factors. Mechanical weathering, also known as physical weathering, is achieved through physical processes, such as temperature fluctuation, frost action and abrasion. This shows a greater depth of understanding and can help you to unlock those higher marks. Farming changes the chemical composition of soil, mud, and rock.When discussing weathering in exam answers, try to be specific about what type of weathering you are talking about. Acid rain caused by pollution can eat away at rocks and minerals. Mining, of course, changes the location and condition of rocks and soil. Human activities also have a major impact on rock. For example, bat guano and other animal remains contain reactive chemicals that can affect minerals. Frozen water expands, making the cracks wider and further weathering the rock.Īnimals can also effect geochemistry. Once the rock is broken up, water can get into the cracks and oxidize or freeze. New, weaker minerals are often more brittle this makes it easier for plant roots to break up the rock. Plant roots also use carbon dioxide, thus changing the chemistry of the soil. As roots expand into rock, acids can change the minerals in the rock. Plant roots are also an important source of chemical weathering. Lichens, a combination of algae and fungi, produce a weak acid that can dissolve rock. Lichens can have a profound effect on rock. Living organisms perform chemical reactions to obtain minerals from soil and rocks.
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