Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
WEATHERING, EROSION AND SOIL 1 WEATHERING 2 MECHANICAL WEATHERING Temperature Freezing temperature causes the expansion of the molecules of substances - water expands as it freezes Cracks in concrete, wood, etc. fills with water. Water freezes and expands, causing splitting and breaking apart - frost wedging, ex. pot holes. Pressure - factor of mechanical weathering. Bedrock at great depth are under pressure as over lying rock is stripped away. The bedrock at depth is exposed. Then the bedrock can expand and cracks will occur. Exfoliation - stripping of layers of rock - create a dome formation, ex. Stone mountain in Georgia 3 EXFOLIATION Stripping of layers of rock Creates a dome formation Ex, Stone Mountain in Georgia Half Dome Yosemite Valley California 4 CHEMICAL WEATHERING Rocks change composition as the result of chemical reactions. Agents - H2O, O2, CO2, and acids. Temperature tends to speed up and slow down chemical reactions *Rate of chemical Rx (reactions) doubles with each 10°C increase 5 CHEMICAL WEATHERING 6 WATER Universal solvent, hydrolysis - reaction of H2O and other substances Oxygen - oxidation Substance + O2 new substance Fe (Iron) + O2 (Oxygen) Fe2O3 (Rust) Al (Aluminum) + O2 Al2O3 (Aluminum Oxide) 21% of oxygen is in atmosphere Minerals - result of oxidation, Ex. Pyrite, magnetite CO2 - produced through respiration CO2 + H2O H2CO3 (Carbonic Acid, weak acid form in the atmosphere Carbonic acid reacts with calcite forms (limestone caverns) 7 ACID PRECIPITATION Acid Precipitation - Oxidation of sulfur dioxide and nitrogen oxide - that is released by human activities SO2 Industrial emissions NO2 Motor Vehicles SO2 + O2 + H2O Sulfuric acid NO2 + O2 + H2O Nitric acid Acid Rain - PH = less than 5.6 Normal Rain - PH = 5.6 Water in lake - 6 to 8 PH Lower PH kill fish To reverse acidification Acid Ca(OH)2 to the area - Calcium Hydroxide 8 9 10 11 EFFECTS OF ACID RAIN ON PLANTS 12 WHAT EFFECTS THE RATE OF WEATHERING? 2000 years to weathering/centimeter of limestone Climate - major influence on chemical weathering variables: precipitation temperature evaporation Interactions of temperature and precipitation has the greatest effect. Chemical weathering predominates in climate with warm temperature, abundant rainfall and lush vegetation. H2O + CO2 H2CO3 (Carbonic acid - accelerates chemical weathering Location: Central America, S.E. Asia 13 WEATHERING Physical Weathering - dominates cool, dry climates where H2O undergoes repeated freezing and thawing. Extremely cold climates has no chemical weathering Rock Type and Composition - Characteristics of rocks - hardness and resistance to breakdown is dependent on the type and composition of the rock. Easy - Sedimentary - easy to break Igneous Metamorphic - hardest Mechanical Weathering - breaking rocks in small pieces - increases surface area Topography - flat level area - rocks remain in place and undergo changes Hilly area - rocks suffer greater erosion through mass movement 14 MOVEMENT Erosion - movement of material Deposition - materials that are dropped in an area after movement Gravity - associated with erosion - pull materials downward “Agent of Mass Movement” (landslides, mudflows, avalanches) Running water - greatest erosional agent, stronger than wind, carries more material a greater distance 15 GULLY EROSION IN A PASTURE RUNNING WATER THAT BECOMES DEEP AND WIDE (3 METERS) 16 RILL EROSION- RUNNING WATER IN SMALL CHANNELS ON SLOPES 17 COASTAL DEPOSITION AND EROSION Mississippi carries 750 million metric tones of material— deposited into the Gulf of Mexico - forms the delta. Volume of river flow and the action of tides determine the shape of delta. Ocean currents and tides carve out cliffs, arches and other features. Sand particles accumulate on shorelines and form dunes and beaches Sand bars - accumulation of sand underwater create a barrier island - location: lakes, Gulf of Atlantic Coast 18 LANDFORM DEPOSITION 19 SAND BAR 20 AMAZON DELTA 21 GLACIAL EROSION Glaciers cover 10% of the earth. Erosion is large scale and dramatic. Landscape features - waterfalls, lakes, Ex. Great Lakes, finger lakes (New York) 22 LEARN ABOUT GLACIERS http://video.search.yahoo.com/video/play;_ylt=A0S 00MufIgRRAFcA7o77w8QF;_ylu=X3oDMTBvMGQzcT ByBHNlYwNzcgRzbGsDdmlkBHZ0aWQDVjEzMg-?p=Glaciers&vid=44a347f060ab09ddfddd2ffdad4d 5c0a&l=&turl=http%3A%2F%2Fts1.mm.bing.net%2F th%3Fid%3DV.4988343346200648%26pid%3D15. 1&rurl=http%3A%2F%2Fwww.5min.com%2FVideo% 2FLearn-About-Glaciers304218898&tit=Learn+About+Glaciers&c=1&sigr= 11ouvmua1&fr=yfp-t-701&tt=b 23 GLACIER NATIONAL PARK http://video.search.yahoo.com/video/play;_ylt=A0 S00MtABAhRWSIAbQn7w8QF;_ylu=X3oDMTBvMG QzcTByBHNlYwNzcgRzbGsDdmlkBHZ0aWQDVjEzM g-?p=glaciers+form+montana&vid=cfe70ffb5200cd cf7a3802ef57cfef0d&l=&turl=http%3A%2F%2Fts 3.mm.bing.net%2Fth%3Fid%3DV.4614243116187 834%26pid%3D15.1&rurl=http%3A%2F%2Fwww.y outube.com%2Fwatch%3Fv%3DBMslDdswGB0&tit =Canadian+Rockies+and+Glacier+National+Park +2012&c=9&sigr=11ajreimc&fr=yfp-t-701&tt=b 24 25 FINGER LAKES NEW YORK 26 WIND EROSION Areas of limited precipitation and high temperature, Ex. Death Valley 27 WIND EROSION 28 AFTER THE WINDS SUBSIDE 29 FARMING METHODS Stops erosion, conserve moisture, trap blowing snow and protect crops wind barriers ( wind breakers - thick line of trees) Planting methods Plowing methods 30 31 COMBINE DIFFERENT CROPS 32 PLANTING CROPS PERPENDICULAR ON A HILL 33 NO TILL FARMING 34 35 STRIP FARMING 36 DUST BOWL PREVENTION 37 FORMATION OF SOIL Development of Soil - Soil looses covering of broken rock particles and decaying organic matter called humus. Overlays the bedrock. Result of chemical and mechanical weathering and also biological activity. 38 SOIL Soil composition - Soil forms layers. Pieces of rock are broken off from the parent rock. Soil is located above it’s parent rock. H2O sinks down carrying minerals and nutrients through the layer of the soil. Parent rock determines the kinds of minerals, proportion of mineral in soil. Length of formation time depends on the type of rock and climate conditions Soil profile - vertical segments of soil layers - well developed soil - distinct layer 3 main horizons: A - organic/humus - gradual to black color B - poorer developed - rich in clay minerals, forms hardpan layers of soil. Red or brown (iron oxide) C - Directly above bed rock, most weathered parent material 39 SOIL HORIZONS 40 41 42 TOPOGRAPHY Affects the thickness of developing soil. Sloped areas cause particles, little particles are washed away. Soil then, is infertile. South facing slope has more direct sunlight / more vegetation, thick soil. *Valley - soil thick and rich. Vegetation contributes to the buildup of humus and supplies acids to promote the weathering process. Soil Types - Appearance, rate of formation and productivity is determined by climate 43 SOIL Soil varies because of different parent rocks and undergo different climate conditions. Types of plants: animals that live there: topography: length of time the soil has been forming. Soils are classified based on climate conditions. 44 FOUR TYPES OF SOIL 1 2 3 4 polar temperate desert tropical 45 POLAR SOIL 46 TEMPERATE SOIL Supports diverse environments, annual rainfall 50-60 cm, grasslands - abundance of humus, forest - aluminum rich clays Western U.S. rainfall less than 50-60 cm, support grasses and bushes 47 TEMPERATE SOIL SANTA CLARA CA 48 DESERT SOIL Low level precipitation - Less than 25 cm of rainfall per year High level of salts - supports limited vegetation - light in color— composed of salts and gypsum 49 DESERT SOIL 50 TROPICAL SOIL- REDDISH IN COLLOR 51 COMPARISON OF SOIL PROFILE AND CLIMATE 52 PHYSICAL PROPERTIES OF SOIL 53 54 SOIL FERTILITY Soil Fertility - measure how well a soil can support the growth of plants. Factors affect it 1) availability of nutrients and minerals 2) Number of microorganisms present 3) Amount of precipitation 4) Topography 5) Level of acidity Natural/commercially produce. Fertilizers are added to replace minerals. Add nitrates, phosphates, and phosphorus to the soil. Limestone (pulverized) added to soil to reduce acidity and influence crop growth 55