Erosion

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Erosion Noun

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[ee-roh-zhun]

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Erosion

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The geological process where earthen materials are worn away and transported by natural agents like water, wind, or ice.

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Example: This diagram shows how wind causes erosion by moving particles of different sizes: tiny dust is carried (suspension), sand grains bounce (saltation), and larger particles roll (creep).

Front

Weathering Noun

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[weth-er-ing]

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Weathering

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The process that breaks down rocks and other materials on Earth's surface into smaller pieces without transporting them.

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Example: This image shows biological weathering, where a tree's roots grow into a crack in a rock, physically breaking it apart over time.

Front

Deposition Noun

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[dep-uh-zish-un]

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Deposition

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The geological process of laying down or settling eroded sediment in a new location when an agent of erosion loses energy.

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Example: This diagram shows a river slowing down as it enters a lake, causing it to drop, or deposit, the sediment it carries to form a delta.

Front

Runoff Noun

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[ruhn-off]

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Runoff

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Water from precipitation that flows over the land surface instead of being absorbed into the ground, causing erosion.

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Example: This diagram shows how rain on exposed soil causes water to flow over the surface (runoff), carrying soil particles away and causing erosion.

Front

Sheet erosion Noun

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[sheet ee-roh-zhun]

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Sheet erosion

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The uniform removal of thin layers of topsoil from a land surface by the action of rainfall and unchanneled runoff.

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Example: This diagram shows sheet erosion as the removal of a thin, uniform layer of soil from the land surface by flowing water.

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Rill erosion Noun

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[ril ee-roh-zhun]

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Rill erosion

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A form of erosion that occurs as runoff flows, creating numerous small, shallow channels or grooves in the soil.

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Example: This image shows small channels, called rills, carved into the soil by flowing water, which carries away sediment.

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Gully erosion Noun

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[guhl-ee ee-roh-zhun]

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Gully erosion

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A severe form of water erosion where rills merge to form larger, deeper channels that cannot be smoothed by tillage.

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Example: This image shows how concentrated water runoff on a sloped farm field carves a large channel, called a gully, into the bare soil.

Front

Meanders Noun

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[mee-an-ders]

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Meanders

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Large, winding loops or curves in a river's channel, typically formed on gentle slopes or across a floodplain.

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Example: This diagram shows how a river's path changes over time, with the 'Before' path being straighter and the 'After' path showing winding curves (meanders).

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Oxbow lake Noun

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[oks-boh layk]

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Oxbow lake

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A U-shaped body of water that forms when a wide meander from a river is cut off from the main channel.

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Example: This diagram shows the three-step formation of an oxbow lake, where river erosion and sediment deposition cut off a meander, leaving a U-shaped lake.

Front

Abrasion Noun

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[uh-bray-zhun]

Back

Abrasion

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The mechanical process of scraping or wearing away rock surfaces by the friction and impact of moving particles.

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Example: This diagram shows a glacier carrying rocks that scrape and wear away the ground underneath as it moves. This scraping action is a type of erosion called abrasion.