Weathering, Erosion, & Deposition

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Weathering, Erosion, & Deposition. Learning Target : I can analyze the effects of weathering, erosion, and deposition on the environment in Texas Ecoregions. The Cycle of Changing Earth’s Surface. - PowerPoint PPT Presentation

Text of Weathering, Erosion, & Deposition

Weathering, Erosion, & Deposition

Learning Target:I can analyze the effects of weathering, erosion, and deposition on the environment in Texas Ecoregions.Weathering, Erosion, & DepositionWebsite: http://www.google.com/#sclient=psy&hl=en&q=weathering+and+erosion+texas&aq=f&aqi=g-j2&aql=&oq=&pbx=1&bav=on.2,or.r_gc.r_pw.&fp=524f32e4dee1b3fc 2nd link1The Cycle of Changing Earths SurfaceWeathering, erosion, and deposition act together in a cycle that wears down and builds up Earths surface

Weathering-wears down the Earths surfaceErosion-moves the Earths surface (acts as a bridge between the weathering and deposition)Deposition-builds up the earths surfacePlease draw this in your notesWeatheringThe breaking down and/or wearing away of earth materials (rocks) into smaller piecesMust occur before erosion can happenNo movement is involved

Sediments- naturally-occurring material that is broken down by processes of weathering; small/tiny pieces of rock

Physical WeatheringPhysical/Mechanical weathering-the breaking down of rocks into smaller pieces (wind, flowing water, ice, gravity, animals/plants, temperature changes)

Physical Weathering

The steep walls here were carved out by moving water

Palo Duro Canyon in the High Plains EcoRegionPhysical Weathering

Enchanted Rock in the Llano Uplift Ecoregion

Exfoliation-warming and cooling of rocks over time causes rocks to peel into sheets Chemical Weathering

Chemical Weathering

This cave was formed by slightly acidic water dissolving the limestoneChemical weathering-occurs when chemical reactions dissolve the minerals in rocks or changes them into different minerals (rusting, acid breakdown, etc)Chemical Weathering

Karst Topographyan area where there is a layer of limestone near the surface that groundwater erosion can significantly change the shape of the land. Deep valleys and caverns are common, but surface streams are rare because the water sinks easily down into the weathered limestone. Sinkholes are common.Lets comparePlease draw a Venn diagram and compare chemical and physical weathering.How are they alike? How are they different?Physical weatheringChemical weatheringErosionThe movement of weathered earth materials by moving water, wind, gravity or ice

Ex: waves causing beach erosion (shoreline of Texas is disappearing) running waterhttp://www.glo.texas.gov/what-we-do/caring-for-the-coast/coastal-erosion/causes-of-erosion.htmlEx: sand storm windEx: rain causing a mudslide running water and gravityEx: landslide gravityEx: rain carrying soil and gravel down a driveway running water and gravity

Erosion

Galveston Texas before/after Hurricane IkeErosion

A gorge is a ravine with nearly vertical walls. This gorge was cut when heavy rains pushed a flood over Canyon Lake Dam in central Texas in 2002.

Erosion

The Bernard Glacier in Alaska's Saint Elias Mountains looks like a huge alpine highway. Glaciers are slow but highly effective shapers of the land, essentially carrying away anything in their pathfrom soil and rocks to hills and even the sides of mountainsWhy care about erosion?Human activities such as construction increase the rate of erosion 200, even 2,000 times that amount. When we remove vegetation or other objects that hold soil in place, we expose it to the action of wind/water and increase its chances of erodingThe loss of soil from a construction site results in loss of topsoil, minerals and nutrients, and it causes ugly cuts and gullies in the landscape. Surface runoff and the materials it carries with it clog our culverts, flood channels and streams. Sometimes it destroys wildlife and damages recreational areas such as lakes and reservoirs.

Bare Slopes vs. Vegetation Stabilized Slopes

Mudslide dangerLoss of topsoilClogged storm drainsFlooding problemsExpensive clean upEroded or buried house foundations

Soil in placeLess clean upMinimum erosionProtection for house foundationsLandslides

Landslides- a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments.DepositionThe process of eroded earth materials (sediments) being deposited in a new location

Ex: delta-where sediment is deposited where a river flows into an ocean or lake builds up a landform

Ex: sand dune-a deposit of wind blown sand

Deposition

Desert winds sculpted these gentle swirls out of the limestone hills in Black Gap Wildlife Management Area, Texas. This remote, 100,000-acre (40,470-hectare) area in West Texas contains some of the lowest, driest, and hottest areas in the Chihuahuan DesertDepositionDeposition area from the Rio Grande River

The Red River carries sediments, and drops some along the wayWhat is an ecoregion?A relatively large unit of land or water that is characterized by a distinctive climate, ecological features and plant and animal communities (Source: National Geographics Strange Days on Planet Earth

Weathering & Erosion

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