Presentation on theme: "Weathering & Erosion Vocabulary"— Presentation transcript:
1Weathering & Erosion Vocabulary Shaping the World We Live InBy Stacie Smith 2005 Revised by C.Hundley
2Weathering & Erosion Vocabulary Weathering -surface processes that works to break down rock.ExfoliationFrost WedgingEnchanted Rock
3Weathering & Erosion Vocabulary Mechanical weathering-occurs when rocks are broken apart by physical processes. The overall chemical makeup of the rocks stays the same.
4Weathering & 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.
5Weathering & 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 limestoneLimestone – contains remnants of dead organisms
6Weathering & 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 NewfoundlandIron rich soil
7Weathering & Erosion Vocabulary Soil – mixture of weathered rock, decayed organic matter, mineral fragments, water, and air that can take thousands of years to develop
8Weathering & Erosion Vocabulary Terracing – farming method used to reduce erosion on steep slopes.
9Weathering & 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”
10Weathering & 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.
11Weathering & 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 sunPhotograph by Edwin Harp
12Weathering & Erosion Vocabulary Abrasion- a type of erosion that occurs when windblown sediments strike rock, polishing and pitting the surface.Water can carry abrasive rocks
13Weathering & 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.
14Weathering & ErosionRiver 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
15Weathering & Erosion Stages of stream development Young Stream flows swiftly through a steep valleyErodes the streams bottom faster than the sidesMature stream flows more smoothlyErodes more on its sidesCurves form called meanders and flood plains
16Weathering & Erosion Stage of stream development Old stream flows slowly through a floodplain it has carvedFlat valley floor called a floodplain
17Weathering & ErosionFlooding is when too much water enters a river system, it over flows its banks.Dams built to control the flow of water downstreamLevees mounds of earth built along the sides of the river to prevent flooding
18Weathering & Erosion Vocabulary Groundwater-water that soaks into the ground and collects in pores and empty spaces and is an important source of drinking water.
19Weathering & Erosion Vocabulary Permeable – describes soil and rock with connecting pores through which water can flow (example sandstone)
20Weathering & Erosion Vocabulary Aquifer – a layer of permeable rock that lets water move freely (Austin example: Edwards Aquifer)
21Weathering & Erosion Vocabulary Water table – the upper surface of the zone of saturation; drops during a drought
22The Dust Bowl 1930s Lasted for a decade Caused floods due to lack of vegetationFamilies movedNo foodNo money (farms useless)Dust StormsLack of agricultureFarmers learned something from the events of the dust bowl