Soil and Erosion

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Weathering Noun

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[weth-er-ing]

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Weathering

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The process of breaking down rocks, soils, and minerals into smaller pieces at or near the Earth's surface.

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Example: This image shows a large rock split in two, a clear example of physical weathering, which is the process of breaking down rocks into smaller pieces.

Front

Erosion Noun

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[ih-roh-zhuhn]

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Erosion

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The removal and transport of weathered material from one location to another by agents like water, wind, or ice.

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Example: Faster water on the outside bend of a river has more energy, causing it to wear away and carry off soil from the bank.

Front

Deposition Noun

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[dep-uh-zish-uhn]

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Deposition

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The geological process in which sediments, soil, and rocks are added, or dropped off, to a landform or land mass.

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Example: As a river enters a lake, it slows down and drops the sediment it carries, forming layers of deposits on the lakebed and building a delta.

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Mechanical Weathering Noun

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[muh-kan-i-kuhl weth-er-ing]

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Mechanical Weathering

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The physical process of breaking down rock into smaller pieces without changing its chemical or mineral composition.

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Example: A tree's roots grow into cracks in rock, physically forcing the cracks to widen and break the rock apart without changing its chemical composition.

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Chemical Weathering Noun

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[kem-i-kuhl weth-er-ing]

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Chemical Weathering

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The process that transforms rock into one or more new compounds through chemical reactions, altering its mineral composition.

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Example: Chemical reactions, such as with acid rain, dissolve minerals in rock over time, causing the stone to break down and form rounded pits and cavities.

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Mass Movement Noun

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[mas moov-muhnt]

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Mass Movement

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Any type of erosion that happens as gravity moves large amounts of rock, soil, and other materials down a slope.

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Example: This diagram shows how gravity causes mass movement, where weak, muddy earth, saturated with water, collapses and slides downhill as a single unit.

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Landslide Noun

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[land-slide]

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Landslide

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The rapid and often destructive movement of rock, debris, or earth sliding down a steep slope under gravity's influence.

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Example: This diagram shows a landslide, where weak, muddy earth and saturated rock on a slope collapse and slide downhill due to gravity.

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Creep Noun

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[kreep]

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Creep

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The very slow, gradual downhill movement of rock and soil, often caused by the repeated freezing and thawing of water.

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Example: When water in soil freezes, it pushes a particle up. When the ice melts, gravity pulls the particle straight down, causing slow downhill movement.

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Delta Noun

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[del-tuh]

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Delta

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A triangular landform built up from the deposition of sediment where a river flows into an ocean, lake, or sea.

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Example: This diagram shows a river slowing down as it enters a lake, causing it to drop the soil and sediment it carries, building a landform called a delta.

Front

Groundwater Noun

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[ground-waw-ter]

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Groundwater

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Water that is held underground in the soil or in the pores and crevices of rock and rock layers.

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Example: Rainwater seeps through the soil (infiltration) and collects in a porous underground layer called an aquifer, forming groundwater above solid bedrock.