There are many affects of weathering. Many factors influence the susceptibility of rocks to chemical and mechanical weathering. Rainfall, biologic activity, abundance of openings, composition of the rock, amount of vegetation, temperature, and tectonic settings are important factors in the weathering process. External forces like wind, water, and ice are constantly causing changes in the surface of rocks. These activities are cutting some material away while depositing other materials here and there. This process landscapes the Earth as we see it. Weathering falls into two categories, mechanical weathering and chemical weathering. Mechanical weathering is where a rock physically breaks down into pieces but does not change the mineral content. Chemical weathering is where minerals dissolve and is replaced with new minerals that are stable at the surface of the Earth. Although chemical weathering and mechanical weathering are clearly different, they almost always occur together. This even makes it difficult to sometimes determine if an effect is caused by chemical weathering or mechanical weathering. Even though weathering is broken down into two categories of chemical weathering and mechanical weathering, each of these categories is broken down even further. Even with the further break down of these categories, most of the weathering is done gradually.
Erosion
The effects of erosion are described as the transport of regolith from one place to another. In order for erosion to occur natural fluids to pick up and transport the eroded material. Water, wind, and ice are the fluids that cause most of the erosion of Earth. Water erosion happens in two ways, impact which happens when raindrops hit the ground and dislodge small particles of soil, and by the overland flow which happens during heavy rains. Overland flow is where water moves in sheets over the ground and not in channels. Erosion by wind is mostly occurs slowly with the transport of sediment through saltation of sand grains. Only the dust remains aloft long enough to be moved by the wind through suspension. There are of course exceptions to this, hurricanes and tornadoes can and do move coarse rock particles several centimeters in diameter. Although ice is solid, if flows under the influence of gravity in parts of the world where there is enough ice all year long to form a glacier. Ice moves at a very slow pace. Acting as a file, sled, and plow, ice plays a role in erosion and transport. Unlike wind and water, ice is very viscous and moves only by a laminar flow.
The Differences
The differences in weathering and erosion are as follows: Weathering involves two processes that often work together to decompose rocks. Mechanical weathering which involves physically breaking rocks into fragment with any change to their chemical make-up of its minerals within. Chemical weathering which is a chemical change in at least some of the minerals within a rock is the second process. Each one of these two processes occurs in place, there is no movement involved in weathering. It is important to remember that weathering is a surface or near surface process. When particles are loosened by one of the two processes of weathering it moves and then is called erosion. We call this erosion if the particle is moved by some flowing agent such as ice, wind, or water. Mass wasting, which is a form of erosion is movement down a slope due to gravity. Some examples of mass wasting are debris flows, rock falls, and slumps. Basically is a particle is loosened, chemically or mechanically but stays put, we call it weathering. Once the particle starts moving, we call it erosion. Weathering, be it chemical weathering or mechanical weathering and erosion can and do take place in the same area often.
