Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.
Concept
Attrition (erosion)
Summary
Attrition is the process of erosion that occurs during rock collision and transportation. The transportation of sediment chips and smooths the surfaces of bedrock; this can be through water or wind. Rocks undergoing attrition erosion are often found on or near the bed of a stream. Attrition is also partially responsible for turning boulders into smaller rocks and eventually to sand.
Attrition erosion allows past and present geologic changes to be understood as well as paleogeomorphic environments to be interpreted. Researchers use particle shapes (a result of attrition) to study erosion and environmental changes.
The amount of attrition is dependent on a number of factors: particle properties such as size, shape, surface, porosity, hardness, and cracks, as well as environmental properties such as time, velocity, pressure, shear, and temperature.
Generally, particles are more affected by attrition farther downstream, as the rivers' velocity tends to be higher, and therefore its competence (ability to carry sediment) is increased. This means that the load rubs against itself more and with more force when suspended in the river, thus increasing erosion by attrition. Although there is a point after transport over a certain distance that pebbles reach a size that is relatively immune to further attrition. Grain-size distribution of sediments produced by attrition will also be controlled by the lithology of the rock from which they are derived. Particle sizes generally decrease continuously as the river flows farther downstream, in a process called downstream fining. Since attrition affects pebble size it also affects the movement of the pebbles, and the size and condition of pebbles can explain past conditions of waterways, such as flow.
Rates of erosion by attrition are affected by the rocks shape, lithology, and the energy of impact, therefore, softer rocks are more susceptible to attrition erosion. As attrition and breakage occur on a bedrock it becomes suspended: down-stream of a river or waterway the bedload increases due to attrition.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.