Weather, Erosion, and Deposition

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Weathering

Physical and chemical breakdown of rocks at or near the surface

Physical weathering

The mechanical breakdown of rock into smaller pieces without a change in the mineral's composition

Frost Action

Water freezes in a crack of rock surface, expanding and splitting the rock. Alternate freezing and thawing form pot holes and frost heave.

Plants and animals

Plant roots force their way into cracks, and ____ expose rocks to the surface by digging.

Exfoliation Dome

Layers of rock peel off the main body of the rock

Temperature Change

Alternating hot and cold weakens the rock as it expands and contracts

Abrasion

Pieces of rock collide with each other due to transportation by wind, ice, water, and gravity

Chemical weathering

The process by which chemicals breakdown rock through a change in its composition. Happens fastest in hot and moist climates

Oxidation

Occurs when oxygen from the air combines with iron-rich minerals of the rock. (Rust)

Carbonation

Occurs when water combines with carbon dioxide in the air to form carbonic acid.

Carbonic Acid

Easily dissolves limestone and marble

Hydrololysis

Water combines with minerals such as mica and feldspar found in granite, to form clay, the rock weakens and crumbles apart.

Exposure

Rate and type of weathering are dependent on exposure to air, water, and living things.

Particle size

An increase in surface area increases the rate of weathering.

Mineral Composition

Rocks made of harder minerals weather slower than rocks made of softer minerals

Climate

Physical and chemical weathering are affected by this.

Cold/moist

Physical weathering is dominant here

Hot/moist

Chemical weathering is dominant here

Time

As this goes by more weathering will occur

Humans

Excavation of land, minding, building, etc. affect rate of weathering because of these.

Soil formation

End product of weathering and biological activity

Parent Material

Bedrock.

Residual Soil

Soil is formed from the parent material and is of the same composition

Transported Soil

Parent material has been carried from elsewhere and deposited. Soil is also a different composition than where it is found

Arid climate

Climates that have thin soils, high in mineral content, low in organic matter. (Grand canyons, plateaus)

Humid climate

Climates have thick soils, high in organic matter, low mineral content

Organisms

Dead and decayed plant and animals add nutrients forming topsoil

Time

The longer the weathering, the deeper the soil.

Erosion

Transportation of sediments produced from weathered rock.

Gravity

Primary driving force for all transporting agents.

Angular

Sediments that fall short distances so they have sharp edges.

Mass Movement

Land slides, avalanches, mudflow, and slump.

Running Water

Primary agent of erosion on earth.

Gradient

Steeper the slope, the faster the water's velocity of this.

Discharge

The more ___ the grater/faster the stream velocity

Channel Slope

In a straight channel- water is fastest below the surface and in the center

Stream Load

The material a stream carries

Solution

Dissolved particles (ions)

Suspension

So tiny that they take a very long time to settle. They tend to "hang" in the water (clay, silt, sand)

Saltation

Larger sediments that are too big to be lifted so they bounce, roll, or are pushed along. (Abrasion is found when this happens)

Meanders

Bends or curves in the river

Oxbow

When meanders "close off" and leave behind a horseshoe-shaped lake

Young stream

Stream that has v-shaped valleys, rapids/waterfalls, steep slopes, no flood plains, and valleys are deepened

Mature stream

Stream where divides begin to round off, sediments build up, flood plain widens, and river begins to meander

Old Stream

A stream with very wide flood plains, land worn down to flat surface, pronounced river meanders, and oxbow lakes.

Watersheds/drainage basins

The area of land drained by one stream

Wind erosion

Wind carries small sediments, occurs mainly in deserts and along coastlines. Looks pitted and frosted. Freckles.

Wave action

Influenced by water depth, energy from winds/storms, and shape of shoreline.

Long-Shore Currents

Because waves strike the shore at an angle, the water near shore is pushed in one direction along the shore causing this. Sediments are carried in the same direction as the current

Glaciers

Mass of ice and snow. These are influenced by accumulation of ice and snow. Looks like there are scratches and grooves. Sediments are very unsorted. Form U-shaped valleys

Deposition

Process by which sediments are released, settled from or dropped from an erosional system. It occurs when the stream velocity decreases

Talus Cone

Sediment that is found at the base of a hill or mountain. Unsorted.

Sand bar

Cause of running water and wave action. Build up of sediment from wave action

Delta

Fan shaped deposit of sediment at the mouth of a river

Beach formation

Deposition takes place on the side of the grain that the long-shore current is coming from

Horizontal sorting

Occurs when a stream enters a lake; as kinetic energy decreases, the large, rounder, high density sediments are deposited near the mouth of the stream.

Sand dunes

From wind. The gentle slope faces the direction the wind came from.

Cross- Bedding

Diagonal sand deposits caused varying wind direction and velocity

Till

Unsorted sediment deposited by a glacier

Moraine

Till found along the sides or leading edge of a glacier

Drumlins

Elongated hills sculpted by a glacier's retreat; they indicate the glacier's flow.

Eskers

Long winding ridges of sand and gravel typically oriented parallel to ice flow. They were deposited by glacial melt water, in, on, or beneath the ice

Kames

Mounds or hills are created when drift fill a hole in a glacier. When the glacier recedes the mound is left behind

Kettle Lakes

Formed when large blocks of ice break from the face of the glacier and are buried in sediment. when these blocks melt, they leave circular depressions.

Erratics

Large boulders that were deposited when the glacier melted

Outwasn Plain

Melted water that washes out from under the glacier carrying sediments. Sorting will occur with a decrease in velocity.

Sediment

Rocks into smaller particles.

Colloid

Very small solid particles that are too small to be seen with an ordinary microscope, and too light to settle in water. Even in calm water they will stay suspended.

Soil

Combination of weathered rock and organic matter.

Humus

Decayed plant and animal material found in soil.

tributary

Smaller streams which flow into larger streams and rivers.

Divide

Ridge or section of a high ground between drainage basins

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