Weathering & Erosion VocabularyShaping the World We Live In

By Stacie Smith 2005 Revised by C.Hundley

Weathering & Erosion Vocabulary

• Weathering -surface processes that works to break down rock.

Exfoliation

Frost Wedging

Enchanted Rock

Weathering & Erosion Vocabulary• Mechanical

weathering-occurs when rocks are broken apart by physical processes. The overall chemical makeup of the rocks stays the same.

Weathering & Erosion Vocabulary

• Chemical weathering- occurs when chemical reactions dissolve the minerals in rocks or changes them into different minerals. This changes the chemical composition of the rock, which can weaken the rock.

Weathering & Erosion Vocabulary

• Carbonic acid – a weak acid formed when water mixes with carbon dioxide from the air – weathers such rocks as limestone to form caves.

Moister in caves combines with carbon dioxide to form a carbonic acid that dissolves limestone

Limestone – contains remnants of dead organisms

Weathering & Erosion Vocabulary

• Oxidation – a chemical reaction which occurs when metallic materials are exposed to oxygen and water over a long period of time.

Photograph of rust-stained outcrops produced by oxidation

weathering of iron-rich rock near Trout River, western Newfoundland

Iron rich soil

Weathering & Erosion Vocabulary

• Soil – mixture of weathered rock, decayed organic matter, mineral fragments, water, and air that can take thousands of years to develop

Weathering & Erosion Vocabulary

• Terracing – farming method used to reduce erosion on steep slopes.

Weathering & Erosion Vocabulary

• No-till farming- a farming method which provides cover for the soil year-round, thus reducing water runoff and slowing soil erosion

"At the time that we were conventionally tilling, we were losing over nine tons of soil to the acre. After going to no-till, we reduced our soil loss to less than five tons”

http://www2.kenyon.edu/Projects/Famfarm/environ/styles/chart.htm

Weathering & Erosion Vocabulary

• Erosion- process in which surface materials are worn away and transported from one place to another by agents such as gravity, glaciers, wind and water.

Weathering & Erosion Vocabulary

• Deposition – dropping of sediments (rock, sand, etc) when the wind, water, glacier, etc. loses its energy and can no longer carry the load.

Rock fall deposition, Yosemite National Park, California-On July 11, 1996, at 6:52 p.m.), two large rock blocks, with a combined volume of between 23,000 and 38,000 m3 broke away from Glacier Point. The rock disintegrated when it landed, creating an air blast that was so powerful that it flattened as many as 2,000 trees in the area. Dust from the pulverized rock blocked out the sun Photograph by Edwin Harp

Weathering & Erosion Vocabulary

• Abrasion- a type of erosion that occurs when windblown sediments strike rock, polishing and pitting the surface.

Water can carry abrasive rocks

Weathering & Erosion Vocabulary

• Runoff- any rainwater that does not soak into the ground or evaporate but flows over earth’s surface; generally flows into streams and has the ability to erode and carry sediments.

Weathering & Erosion

• River system – the network of groundwater and streams that come together to form a river .

• Mississippi River drainage basin is the largest in the United States

Weathering & Erosion

Stages of stream development

• Young Stream flows swiftly through a steep valley

Erodes the streams bottom faster than the sides

• Mature stream flows more smoothly

Erodes more on its sidesCurves form called

meanders and flood plains

Weathering & Erosion

Stage of stream development

• Old stream flows slowly through a floodplain it has carved

Flat valley floor called a floodplain

Weathering & Erosion

• Flooding is when too much water enters a river system, it over flows its banks.

• Dams built to control the flow of water downstream

• Levees mounds of earth built along the sides of the river to prevent flooding

Weathering & Erosion Vocabulary

• Groundwater-water that soaks into the ground and collects in pores and empty spaces and is an important source of drinking water.

Weathering & Erosion Vocabulary

• Permeable – describes soil and rock with connecting pores through which water can flow (example sandstone)

Weathering & Erosion Vocabulary

• Aquifer – a layer of permeable rock that lets water move freely (Austin example: Edwards Aquifer)

Weathering & Erosion Vocabulary

• Water table – the upper surface of the zone of saturation; drops during a drought

The Dust Bowl

• 1930s• Lasted for a decade• Caused floods due

to lack of vegetation• Families moved

• No food• No money (farms useless)

• Dust Storms• Lack of agriculture• Farmers learned something

from the events of the dust bowl

Weathering & Erosion Concept Map

Caused by

Caused by

Types of Weathering

Chemical Mechanical

Carbonic Acid

Plant acids

Oxidation

Growing plants

Burrowing animals

Expanding ice

Resources

• http://www.ptsi.net/user/museum/dustbowl.html

• http://www.usd.edu/anth/epa/dust.html

• http://www.gpc.edu/~pgore/geology/historical_lab/weathering.php

• http://images.google.com/images?hl=en&lr=&q=Zone+of+Saturation