Lesson 1 Weathering Types of Weathering 1 Physical

Lesson 1 Weathering

Types of Weathering… 1. Physical weathering … rocks & minerals break down into smaller pieces. http: //www. kidsgeo. com/geology-for-kids/0066 -mechanical-weathering. php

Physical Weathering… a. Frost wedging … water in cracks expands as it freezes, wedging the rock apart & splitting it! http: //mail. colonial. net/~hkaiter/wxerosglacier. html http: //www. gly. uga. edu/railsback/Field. Images/Clava. Weathering. jpeg

Physical Weathering… b. c. Exfoliation … overlaying rocks removed by erosion, pressure reduced, outer layers crack & are stripped away. This can also occur due to land rebound after a http: //hays. outcrop. org/GSCI 320/lecture 3. html

Chemical Weathering 2. Chemical weathering is the process by which… rocks / minerals undergo changes in composition as result of chemical reactions. (change chemically) http: //i. ehow. co. uk/images/a 05/ne/08/factors-affect-chemical-weathering-1. 1 -800 X 800. jpg Water is a major factor in weathering.

Chemical Weathering: Water a. Water… It dissolves minerals and rocks. This results in the formation of clay minerals. kaolinite Clay comes from felsic rocks and can be molded and heated into pottery.

Chemical Weathering: Oxygen b. Oxygen in atmosphere combines with iron in rocks & minerals. This results in rust (red rocks).

Chemical Weathering: Carbon Dioxide c. Carbon Dioxide… It combines with water (H 2 O) in atmosphere or soil forming weak carbonic acid. This results in clay or caves.

Chemical Weathering: Acid Precipitation Acid precipitation … rain, snow, sleet mixed with gases in the atmosphere that turn these forms of water into a weak acid (p. H < 5. 0). d. II. III. IV. sulfur dioxide and nitrogen oxide The most common source – coal-fired power plants It is also known as acid rain, It causes lakes to become more acidic than living things can handle. AND… It chemically weathers nonliving things like statues and buildings See next slide…

Factors That Affect Weathering…Climate 1. Chemical weathering occurs most rapidly in climates that are… warm & humid. Places such as Central America and S. E. Asia (tropical places). Note the intensely weathered soil. http: //www. geotimes. org/july 08/trends 1. jpg

A. Factors That Affect Weathering…Climate 2. Physical weathering occurs readily in climates that can get cold. In the winter places such as the Appalachian Mountains experience frost wedging.

http: //www. travelpod. com/travel-blog-entries/gensphoto/1/1280057679/tpod. html B. Factors That Affect Weathering…Rock Type and Composition 1. 2. 3. Sedimentary rocks are more easily weathered than… …harder igneous and metamorphic rocks. The fall line is created by harder, erosion-resistant rock gives way to easily-eroded rock of coastal plains.

C. Factors That Affect Weathering… Surface Area 1. 2. 3. As pieces of minerals & rocks get smaller, their surface area increases. This speeds chemical weathering b/c more total surface area is available for chemical weathering. Draw p. 162. http: //www. mrsciguy. com/sciimages/surfacearea. jpg

http: //www. geoproducts. org/App-Slope. Erosion. Control. aspx D. Factors That Affect Weathering… Topography 1. 2. Materials on level (flat) areas are likely to remain in place as they undergo changes. Material on slopes have a greater tendency to move as a result of gravity. Controlling weathering/erosion on slopes can be big business!

Lesson 2 Erosion by Running Water

Introduction… 1. What is erosion? Ø process that transports Earth’s materials from one place to another 2. Why is gravity associated with many agents of erosion? Ø It pulls all materials down slope! Five forces or agents of erosion include: running water, glaciers, wind, gravity, and human activity. http: //www. awi. de/en/news/press_releases/detail/item/scientists_expect_increased_melting_of_mountain_glaciers/? c. Hash=10 a 73716 ccb 3 df 05543 dca 09 d 1 f 65 e 50

Erosion By Running Water… 1. Water has more power than wind to move large objects. 2. Rill erosion… small channels carved by water form on the side of a slope. 3. Gully erosion… a rill becomes deep and wide. http: //www. soils. umn. edu/academics/classes/soil 2125/img/10 riller. jpg http: //plantandsoil. unl. edu/croptechnology Gully Erosion

http: //www. learner. org/courses/envsci/visual. php? shortname=gully_erosion Erosion by Running Water… 4. Gully erosion is usually caused when too much vegetation is removed.

Erosion by Running Water… 5. Rocks exposed to their surrounding environments are slowly weathered away then… streams and rivers carry these sediments to coastal areas. http: //earthasart. gsfc. nasa. gov/mississippi. html The Nile River http: //www. sciencekids. co. nz/pictures/earth/nileriverdelta. html

6. Canyon Erosion in Canyonlands National Park, UT

Waves erode rocky coastlines…

http: //farm 1. static. flickr. com/121/259022625_5073 e 03 db 2. jpg Deposition by Running Water… 1. The Mississippi River carries sediment into the Gulf of Mexico. Ø Ø It drains about 43% of the USA! It drains the land west of the Appalachians and east of the Rockies.

The Mighty Mississippi! http: //www. nps. gov/miss/riverfacts. htm

Deposition by Running Water… 2. Deltas are formed when rivers deposit sediments in the mouth of a bay or gulf. Ø This forms a triangular -shaped deposit. Ø New Orleans is built on the Mississippi Delta.

Deposition by Running Water… 3. An alluvial fan is… a fan-shaped deposit that forms when running water carries sediment through a narrow mountain valley.

Deposition by Running Water… www. skywalker. cochise. edu Eroded olivine forms a green sand beach in Hawaii.

Deposition by Running Water… Eroded basalt forms a black sand beach in Hawaii.

Deposition by Running Water… Eroded limestone forms a white sand beach in Florida.

Lesson 3 Erosion by Glaciers

http: //www. geocaching. com/seek/cache_details. aspx? guid=50953 ee 7 -2 a 7 a-4 cf 9 -b 8 f 5 -964 ec 62 c 8913 Introduction… 1. Glaciers change Earth’s surface by… a. scrape & gouge out large sections of land. b. carry huge rocks & debris piles over great distances c. Polish surfaces http: //www. physicalgeography. net/ fundamentals/10 af. html Glacial Grooves on Kelly’s Island in Lake Erie (one of the great lakes!)

Introduction: Glacial Erosion… 2. Many features of glacial erosion are found in the states of New England the Midwest. This is an esker – a landform left by glacial erosion in the Adirondacks. http: //merryatsyracuse. blogspot. com/2010/09/stillwater-esker. html

http: //www. geographypages. co. uk/a 2 glac. htm Introduction: Glacial Erosion… 3. What is a glacier? Ø Ø travelpod. com A large moving mass of ice! Glaciers are the most powerful erosive force on Earth. The Jungfrau Glacier in Switzerland

Introduction: Glacial Erosion… 4. There are two types of glaciers. A valley glacier forms in mountainous areas a. b. Valley glaciers will carve Ushaped valleys. Valley glaciers are found in the Rocky Mountains. Valley glaciers in the Rocky Mountains

Introduction: Glacial Erosion… 5. A continental glacier covers large continent sized areas. a. b. They are also called ice sheets. Examples include Greenland Antarctica. http: //web. arc. losrios. edu/~borougt/Continental. Glaciers. gif

Glacial Erosion… 1. Glacial erosion carve out the following features… a. Cirque – a bowl shaped depression b. Arête – sharp, steep ridge c. Horn – pyramidshaped peaks Glacial Features online… http: //rst. gsfc. nasa. gov/Sect 17_5 a. html http: //www. scienceclarified. com/landforms/Faults-to-Mountains/Glacial-Landforms-and-Features. html

2. Glacial Grooves… n Caused by … glaciers plucking up large rocks and dragging them over the bedrock.

Glacial Deposition… 1. Glacial till is the mixed debris that glaciers carry embedded in their ice. 2. A moraine is a ridge of till that’s been bulldozed by a glacier. http: //rst. gsfc. nasa. gov/Sect 17/moraine. jpg

Glacial Deposition… 3. An outwash plain is a plain where glacial melt water and debris are deposited. http: //rst. gsfc. nasa. gov/Sect 17/outwash_plain_DDS 21_Cooper_river_region_Alaska. jpg

Glacial Deposition… 4. Two types of lakes formed by glaciers include… Kettle lakes and cirque lakes a. b. Our most famous lakes are the Great Lakes which are moraine-dammed lakes Huron, Ontario, Michigan, Erie, Superior

Lesson 4 Erosion By Wind

http: //www. saharamet. com/desert/photos. html Introduction… 1. Where is wind a major erosional force? Ø In deserts (hot and dry) AND…

Introduction… … and in coastal areas.

http: //www. sci. uidaho. edu/scripter/geog 100/lect/12 -wind-deserts. htm Introduction… 2. How do plants guard against erosion? Ø Their roots hold onto soil & keep it from blowing away.

http: //www. forestry. ok. gov/windbreaks-shelterbelts Introduction … 3. Windbreaks - tall plants grown perpendicular to direction of wind to keep soil from blowing away Windbreaks in Oklahoma

Introduction … 4. How is wind erosion different from water erosion? Ø It can transport sediment uphill!

http: //www. sci. uidaho. edu/scripter/geog 100/lect/12 -wind-deserts. htm http: //www. calstatela. edu/dept/geology/Deserts/Track. Desert. Pavement(2). jpg Wind Erosion… 1. Deflation … lowering of land due to the wind removing surface particles. The coarse surface left behind is called desert pavement.

Wind Erosion… 2. The Dust Bowl was created by… a. b. c. A severe drought Poor farming practices in which large areas of natural vegetation was removed Strong winds picked up surface particles

http: //www. uwsp. edu/geo/faculty/ritter/geog 101/textbook/eolian_systems/features_wind_erosion. html Wind Erosion… 3. Abrasion… Wind-blown sandblasts surface of rocks Ventifacts… rocks shaped by wind-blown sediments We drove past this ventifact sculpted by the wind in Utah!

http: //static. newworldencyclopedia. org/7/73/Sand_dune_formation. png Wind Deposition… 1. A sand dune is… a pile of wind-blown sand. Four conditions determine a sand dune’s shape… 1. 2. 3. 4. Amount of sand Wind direction Wind speed Amount of vegetation

http: //www. igsb. uiowa. edu/Browse/loeshill. htm Wind Deposition… 2. Loess are thick wind-blown silt deposits (silt dunes). 1. Loess deposits are found in the Midwestern states: Illinois, Iowa, Missouri, S. Dakota, Nebraska, Kansas, and Indiana. 2. They are used as farmlands because they are so fertile. Loess Hills in Iowa

Lesson 5 Erosion by Gravity: Mass Movements

Introduction: Mass Movements… What are mass movements? Ø downslope movement of loose sediments or weathered rock due to gravity 2. Where do all mass movements occur? Ø On slopes! 1. The Grand Tetons in Wyoming http: //www. destination 360. com/north-america/us/wyoming/rocky-mountains

http: //geology. about. com/od/naturalhazardsclimate/ig/Landslides/creepdiagram. htm Creep… 1. Creep is… slow, steady, downhill flow of loose, weathered material a. Creep occurs… On slopes b. Creep changes the landscape by… causes everything on the slope to tilt http: //www. kidsgeo. com/geology-for-kids/0073 -creeps. php

Mudflows… 2. A Mudflow is… fast-moving mud & water a. A Mudflow occurs in … volcanic or semi-arid regions b. A Mudflow causes people and objects to… be swept away c. Mudflows caused by melting snow during a volcanic eruption are called… lahars Mudflow in California http: //www. uwsp. edu/geo/faculty/ritter/geog 101/textbook/mass_movement_weathering/mass_movement_1. html

http: //www. uwsp. edu/geo/faculty/ritter/geog 101/textbook/mass_movement_weathering/mass_movement_1. html Landslides… 3. a. b. c. A Landslide is… thin block of loose Earth slides on bedrock A Landslide occurs on slopes that are… steep & saturated (soaked) with water Factors that trigger a landslide are… excess rain or earthquakes A Landslide causes… $2 billion of damage and deaths each year in the USA http: //sccounty 01. co. santa-cruz. ca. us/oes/landslide%20 and%20 mudflow. htm Landslide in La Choncita, Ca

Slumps… 4. A Slump is… mass of Earth material rotates & slides along a curved surface a. A Slump occurs on … moderate to steep slopes with thick soil b. A Slump changes a slope by causing … crescent-shaped scars A Slump in Teddy Roosevelt N. P. http: //here 4 now. typepad. com/here 4 now/2009/08/theodore-roosevelt-national-park-part-ii-north-unit. html

http: //www. tetonwyo. org/Agency. Topic. asp? topic. ID=201704 Avalanche… 5. An Avalanche is… landslide in snowy mountainous areas a. An Avalanche occurs on… steep slopes with at least a 35º angle b. An Avalanche causes death by … suffocation Avalanche in Teton Co. , Wyoming

Rock Falls… 6. A Rock Fall is… falling rocks! a. A Rock Fall occurs in/on… high elevations, steep road cuts, rocky coasts b. A Rock Fall causes… road blocks & sometimes destruction to property The on I 40 near Asheville took 3 months to clear up! http: //www. knoxnews. com/news/2009/oct/26/engineers-ready-assess-damage-i-40 -slide-site/ http: //www. wbtv. com/global/story. asp? s=11379555