Sculpturing+Earth's+Surface+(chapter+4)

=Unit 3: Sculpturing Earth's Surface (chapters 4)= ==Big Idea: Weathering, Erosion, and Deposition continuously alter and shape the earth's surface.==

Essential Questions:

 * 1) ==How does mass wasting sculpt the earth's surface?==
 * 2) ==Explain how chemical weathering alters materials at the earth's surface?==

ES Standard: Earth Processes and Cycles 3.1

=Question of the Day: What is weathering?=
 * Process by which the earth's surface is altered/changed both chemically and mechanically.
 * Erosion is the process by which weathered material is moved from a location by wind, water, waves, glaciers.
 * Deposition is the process by which eroded material is deposited in a new location and makes new features.
 * All 3, weathering, erosion, and deposition continuously alters and shapes the earth's surface.

Weathering
>>
 * Two types
 * Mechanical: alters the size/shape of rocks but NOT their chemical composition.
 * Smaller pieces wear away faster because the surface area of the rock has increased when the smaller pieces were made allowing for more of the rock to be exposed to weathering.
 * Types of Mechanical Weathering
 * Frost Wedging (aka Frost Action)- water freezes inside cracks and makes them bigger
 * [[image:frostaction.jpeg]]
 * Salt Crystals-crystal deposits left in cracks after water evaporates making them bigger
 * Unloading (aka exfoliation)- flaking off of the surface of a rock due to changes in temperature
 * [[image:unloading.jpeg]]
 * Biological Activity-plants and animals that break material down. IE: tree roots pushing through soil and concrete, animals burrowing in the ground, blasting of rocks for roads
 * [[image:plantaction.jpeg]]
 * Chemical: alters the chemical composition of the rock. Will stay unchanged unless the environment in which it is in changes.
 * Types of Chemical Weathering
 * Water-most important agent because it is the universal solvent and will dissolve almost anything so it can dissolve minerals located in rocks
 * [[image:sinkhole.jpeg]]
 * [[image:oldmanmt.jpeg]]
 * Carbonation- process of Carbonic Acid forming with carbon dioxide mixes with water (as seen in our atmosphere). This weak form of acid rain will dissolve material from rocks.
 * [[image:carbonation.jpeg]]
 * Oxidation-process of oxygen combining with metals to form a new substance as seen with rust. Iron and oxygen produces Iron oxide (RUST). The new substance is brittle and flaky.
 * [[image:oxidation.jpeg]]
 * Acid Rain-stronger acid (Sulfuric acid) created due to the combination of sulfur dioxides and water. Sulfur dioxides enter the air through volcanic eruptions, factory outgasing, and hydrothermal vents.
 * [[image:acidrainweathering.jpeg]]
 * Biological activity- some plants like moss and lichens produce very weak plant acids that help to alter the rocks chemical.
 * [[image:plantacids.jpeg]]
 * Other types of weathering seen involves both chemical and mechanical weathering. Spheroidal weathering is where material is rounded and Differential weathering is where different areas of with a rock are worn away at different rates.
 * [[image:TGA056t.jpg width="400" height="300"]]
 * Rate of weathering depends on
 * Mechanical weathering being present- increase the surface area for chemical weathering to take place
 * Rock composition (minerals that make it up, are they soluble in water...) and it's physical features (does it have cracks in it)
 * .[[image:whs-earthscience/TGA057t.jpg width="480" height="360"]]
 * Climate- amount of temperature and moisture present in the environment. Best environment for things to weather the fastest in is a humid and moist environment.

Soil

 * accumulation of weathered debris along with air, water, and organic matter
 * Half the volume of soil is humus (organic matter) and decomposed rock, the other half is pore spaces that store air, water, and, nutrients. Organic matter is important to retaining water.
 * [[image:TGA058t.jpg width="400" height="300"]]
 * The texture (particle sizes) help to retain and transmit water and air. Prismatic and Blocky textures are good/moderate at water filtration where as Platy and spheroidal textures are poor/slower at water filtration. Classification of Loam is best soil texture for plants.
 * [[image:soiltexture.jpeg width="313" height="276"]]
 * Soil Formation
 * depends on the rate of weathering and soil fertillity
 * Factors that influence soil formation
 * parent material: is it residual (from bedrock beneath the soil) or transported (not the same composition of the bedrock beneath the soil)
 * time: longer the time, more accumulation of material
 * Climate
 * Bioactivity
 * Topography: orientation of the land and if there is a slope angle.
 * Soil Profile is a comprised up of horizontal section of soil. These sections are known as horizons. Mature soil will be well developed and have all horizons present in a profile. Immature soil will lack horizons.
 * Topsoil is comprised up of the O horizon (all organic matter) and the A horizon (minerals with humus)
 * E horizon is the area where there is the leaching zone (minerals leaving top layer and moving down to bottom layers) and the eluviation zone (finer particles moving from top layer to lower layer)
 * B horizon is the zone of accumulation. This is where smaller particles from the E horizon and soluble minerals come to rest. This horizon is also called subsoil.
 * C horizon is partially weathered bedroock
 * D horizon is unweathered bedrock.
 * [[image:TGA060t.jpg width="560" height="420"]]
 * Soil is classified based upon its physical and chemical properties along with observed characteristics.[[image:whs-earthscience/soiltaxonomy.jpg width="560" height="346"]]
 * Soil Erosion happens naturally and is a part of the rock cycle. Sheet erosion happens when water moves over the surface of the earth producing small rills and gullies for more water and sediments to move. Soil erosion was much slower in past generations (9 billion metric tons/year) but due to the increase of construction, logging and farming, soil is eroding away much faster (24 billion metric tons/year). How much erosion happening depends on the climate, slope of the land, and the vegetation. Dust Bowl was a big event that happened that drew attention to the importance of soil.
 * [[image:dust1.jpeg]]

Mass Wasting

 * Influence due to Gravity and is the downhill movement of sediment, soil, and regolith (rock and mineral fragments) Massive mass wasting events happen in areas that are young geologically and even better if it is a young mountain range.
 * Triggers of Mass Wasting events
 * Saturation of water- more water in the soil, easier for soil to move
 * Over-steepening- the steeper the slope the more movement of material down the slope
 * Removal of vegetation- vegetation has roots that help hold soil in place, removing the plants, removes the roots and soil can be moved
 * Earthquakes
 * Mass wasting are classified based upon the motion of the material
 * Fall- freefall of material; material that is detached and moves downward
 * Slides-coherent movement along a well-defined slope
 * Flow- material moves as a viscous fluid. If it is solid/regolith material words such as debris, mud, earth is used. If it bedrock material, the word rock is used. IE: Debris flow, Rock flow...
 * [[image:masswasting.jpg width="390" height="545"]]
 * Types of Mass Wasting Movements
 * Slump is a slow movement in which material moves along a curved slope. Usually seen where there is a lot of clay in the soil.
 * [[image:slump.jpeg]]
 * Creep is a slow movement in which material gradually moves down slope due to the repeated melting/freezing of soil.
 * [[image:creep.jpeg]]
 * Solifluction is when the soil is so saturated with water that it moves downslope a few millimeters ore centimeters at a time. This usually happens where there is lots of clay in the bedrock layer that prevents water from filtering or escaping the soil. Also seen in areas where there is permafrost.
 * [[image:solifluction.jpeg width="287" height="215"]]
 * Rockslides happen in high mountain areas and are a sudden and rapid release of material downslope and usually is more common in the springtime.
 * [[image:rockslide.jpeg]]
 * Debris flow involve the rapid movement of soil and regolith containing large amounts of water. Also known as mudflow. Found in semiarid regions and on the slopes of volcanoes and is confined to the canyons/stream channels.
 * [[image:debrisflow.jpeg]]
 * Lahars are a kind of debris flow that is created when volcanic material becomes saturated with water. This can happen when there are heavy rainfalls or when ice/snow on the volcano suddenly melt as material is heading to the surface during a volcanic eruption.
 * [[image:lahar.jpeg]]
 * Earthflow happen when soil is saturated with water and causes a scarp along a hillside to move downslope. They are slower moving than debrisflows but can move fast during wet periods.
 * [[image:earthflow.jpeg]]
 * Liquefaction happens in regards to earthquakes were porous clay and sand sized sediments become saturated with water and the shaking by the quakes causes buildings to sink/tip or underground items to float to the top.
 * [[image:liquefaction.jpeg]]