& Deposition of Sediments The Process of Erosion & Deposition of Sediments

Erosion and Deposition The transportation and relocation of sediments weathered from rocks

Erosion The moving of rock material from one place to another For erosion to occur, three processes must take place: detachment, lifting of the particles, and transport. There are at least 7 processes that can cause erosion.

Erosion by Wind Small sediments can be carried in the air by the wind. Larger sediments can be rolled along the ground. Suspended particles may impact solid objects, causing erosion by abrasion. Examples: sand dunes, desert pavement, loess

Erosion by Water Fast, moving water has a lot of energy and can carry larger pieces of rocks and sediments. Slow, moving water has less energy and can only carry tiny particles of sediment. When water loses energy, the sediments settle out. Water has the ability to materials over long distances. Examples: canyons, gullies, rills, deltas, splash erosion

splash erosion rill

Erosion by Waves The relentless pounding of waves causes erosion in several ways. Grinding of materials brought by the waves against the shore. This forms sand. This can take over 100 years. Action of saltwater on the minerals in the rocks causes chemical changes in the rock by dissolving the minerals. Strong waves carrying sand strikes the base of a cliff undercutting or breaking the rock

Erosion by Gravity Downward movement of rock and sediment down a slope due to the pull of gravity The process is quite slow and is almost impossible to see until the land mass is no longer able to support itself and falls or slides down a slope. Examples: landslide, slump, mass wasting, sinkhole, creep

creep slump

Erosion by Glacial Ice Ice moves and carries rocks, grinding the rocks beneath it. Plucking happens when materials are picked up by the moving ice and pushed along by the glacier. During abrasion, smaller rocks act like large pieces of sand paper and cause grooves to be carved into the land. Huge U-shaped valleys are cause by continental glaciers.

Bioerosion Bioerosion is the erosion of ocean rocks by living animals. This is done by boring, drilling, rasping, or scraping. Most often done by some mollusks, sponges, chiton, urchins, algae, bacteria, and fish

Deposition The laying down or dropping off of sediments that were carried to a new location from another location. Deposition can be transported by wind, water, or ice.

Deposition by Wind Wind can transport material suspended in the air, hundreds of km from its original location. Heavier materials may be pushed along the ground. Material is deposited when the wind changes direction or loses its kinetic energy. Obstacles, man-made or natural, will often determine where the deposition occurs and the type of feature formed. Ex: dunes, ripples

Deposition by Water Water will carry sediments until the flow slows down enough to drop the sediments. Larger particles are deposited near the shore. Smaller particles settle out farther from the shore. Deposited materials can be seen in river beds, deltas, mud flats, and sand bars.

Deposition by Ice Melting glaciers leave materials behind. Includes huge boulders (erratics), piles of smaller rocks (moraines), glacial lakes, clay, and sand (till) Glacial flows become slower if input is reduced or when the ice begins to melt.