Erosion and deposition

Objective: Explain erosion and deposition, distinguish their meanings, and apply them to a described case.

Erosion: Erosion removes and transports Earth material by water, wind, ice, or gravity. Deposition: Deposition occurs when transported material settles or accumulates. Transport depends on the carrier's energy, particle properties, and flow conditions. A slowing stream may deposit coarse material before fine particles settle, although real deposits reflect changing conditions and multiple events. Glacial deposits are often poorly sorted because ice transports diverse sizes together. Gravity-driven slope failures differ from gradual river transport. A deposit supplies clues about process, but its interpretation should use location and surrounding features as well. Application: A stream carries particles away from a bank. This most directly illustrates erosion. Sand settles where a flowing stream slows. This most directly illustrates deposition.

Objective: Explain sediment sorting and stream competence, distinguish their meanings, and apply them to a described case.

Sediment sorting: Sorting describes the range of particle sizes in a deposit. Stream competence: Competence describes the largest particles a stream can transport under given flow conditions. Transport depends on the carrier's energy, particle properties, and flow conditions. A slowing stream may deposit coarse material before fine particles settle, although real deposits reflect changing conditions and multiple events. Glacial deposits are often poorly sorted because ice transports diverse sizes together. Gravity-driven slope failures differ from gradual river transport. A deposit supplies clues about process, but its interpretation should use location and surrounding features as well. Application: A beach deposit contains grains of similar sizes. This most directly illustrates sediment sorting. A flood moves larger stones than ordinary flow. This most directly illustrates stream competence.

Objective: Explain mass movement and glacial transport, distinguish their meanings, and apply them to a described case.

Mass movement: Mass movement transfers slope material downhill primarily under gravity. Glacial transport: Glaciers move and deposit material ranging from fine particles to large boulders. Transport depends on the carrier's energy, particle properties, and flow conditions. A slowing stream may deposit coarse material before fine particles settle, although real deposits reflect changing conditions and multiple events. Glacial deposits are often poorly sorted because ice transports diverse sizes together. Gravity-driven slope failures differ from gradual river transport. A deposit supplies clues about process, but its interpretation should use location and surrounding features as well. Application: A saturated hillside slides downslope. This most directly illustrates mass movement. Retreating ice leaves an unsorted sediment deposit. This most directly illustrates glacial transport.