Erosion and weathering are the natural forces are responsible for the shape of our environment and are the process in which rocks are broken down into fine particles. Erosion is the process in which rock particles and soil are carried away by wind and water. Weathering, on the other hand, degrades the rocks without displacing it. Weathering often leads to erosion, breaking down the rock into small pieces that are easier for wind and water to carry away.
Types of Weathering
- Physical weathering breaks down a rock's physical structure. For example, in cold environments water that gets into holes in rock and freezes will cause those holes to expand and eventually crack and split the rock. The same process may be caused by salt build-up or growing tree roots. Another form of physical weathering occurs when wind or water causes rocks to rub against each other, smoothing their surfaces.
- Chemical weathering changes the chemical structure of rock, causing it to become softer or more brittle. For example, iron in a rock might react with oxygen to form easily degradable rust, or acids in rainwater may remove calcium from limestone and marble. Chemical weathering often precedes physical weathering, making rocks more vulnerable to forces like wind and rain.
Types of Erosion
Different types of erosion are usually differentiated by the force that carries rock, stone or soil away from its location.
- Water is the most common force that causes erosion. Rivers wear down and carry away rock and soil along their banks. Events such as floods can cause huge amounts of damage and accelerate the erosion process on the river bank.
- Wind erosion can only occur on smaller particles of ash, dust and rock, but it can still move large quantities of these particles from their original locations and create impressive formations, such as sand dunes
- Erosion by ice is rare in most parts of the world, but ice can move much larger rocks than most other erosive forces. Ice may carry huge boulders miles away from their original locations.
- Mass wasting is a specific type of erosion that is caused by gravity and occurs when soil or rocks are carried away by falling or sliding downwards. A rock or landslide is a common example of this.
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Now that you know the difference between weathering and erosion and the different types of each you should be able to answer the below:
- Looking at the side of this stream would you say that the damage was caused by weathering or erosion?
- Based on your answer to question 1 what type of weathering or erosion do you think caused this damage?
- Standing at the GZ please describe the texture and particle size of the damaged ground, from the top down, and state wether you think that further weathering or erosion is likely to happen?
- Post a photo of yourself, gps or any geocaching related object at the bench and include with your log - this is optional.
Please submit your answers to the CO via the geocaching messenger within 7 days of logging your find. Failure to submit answers will result in the found log being deleted.