Dynamic Landscapes PDF

· exogenic Forces : exogenic Forces are Forces that come from the Earths exterior (outside). Weathering is a result of external Forces weathering...

· exogenic Forces : exogenic Forces are Forces that come from the Earths exterior (outside). Weathering is a result of external Forces weathering : the Weathering is wearing down or breaking of rocks and minerals. There are different Types of weathering Physical : Temperature changes · : Drastic of temperature (often desserts changes occurring in dry can result in the constant expansion and compression of rocks that end cracks breakdown may in and eventually. Frost · wedging happens in cold , rainy places. (Rain) Water seeps into a rock's crack and freezes. Due to the freezing , the Water turns into ice and expands. This breaking progress enlarges the crack and can lead to said rock. chemical : · In humid areas like Vietnam and Slovenia, rain droplets pick up carbon dioxide from the air and. When this comes in contact with certain rocks ground -v (mostly limestone) it dissolves forming stalag mites and tites. ↓ acidtwater cald biological : when plants grow in cracks in rocks , they can make the crack and bigger bigger Roots can also cause biological weathering. Roots growing different direction lead to asphalt in can them breaking e. g.  erosion : Erosion is the transport of broken down materials. This often happens through the agents. Examples for agents are : Water, ice wind and , waves. These agents are made mobile by gravity and gradient. Water : Running water like rivers can easily pick up debris and transport it. Waves : The back & forth of cliffs them down and waves repeatedly hitting can wear transport the broken of material at the same time ke : Ice mostly transport through glaciers down mountains and their. These glide pick up material on way. Deposition : Deposition is the relocation of broken down material. The heavy material gets repositioned first. Moraines they transported and depositioned materials Glacier are by a. 2  1) Rivers : 11) Processes of a river : · The river wears away and breaks down lerosion) mud (rivers load) corrasion labrasion) : Rivers load sand and pebbles are boulders , pebbles sand silt and Riverasir e , , longer river it ↑ I dragged along the bed , wearing away River Bed · and carries it downstream (this is called transportation ( attrition rocks each other they knock together away as : · we a r and · When the river looses energy , it can no longer carry it's load becoming smaller m o re rounded and drops it on the river bed (deposition · saltation : Smaller pebbles are picked up and dropped again large and heavy material is deposited first, while light material is deposited last bedload : heavy material is carried along the bottom. 111) Effects on the work of rivers solution : rock like limestone are dissolved by acid in Rainwater > - velocity of the was energy) : the faster the river is= the larger material river transport suspension (Schwebel Tiny particles of sediment in suspension in the : a can are River's current > - volume of the water the more water -the more volume traction : large stones are dragged along and get spun around > - round the bedrock along the river : Hard rocks (granite) erode slowly , making the smooth and soft rocks (shale) erode faster. hydraulic action : fast flowing water is forced into cracks , bank breaking up the over time V) discharge IV) why does deposition happen? discharge-volume of water flowing in a River at a time Idry season-less water, rainy season of snow m e l t more volume deposition happens , when the river looses velocity this be caused can by : > - decrease in gradient ↳ abnahme der Steilheit > - decrease in volume (discharge) after heavy rain ↑ river meeting with sea, , lake or another river (tributary) I often forming a delta 3 VI) River channels : channels consisting of rive bed & walls · S meandering river flows a as n S· straight very few bends · erode might get VII) River courses VIII) upper course upper course middle course lower course · river starts at the source # · upland or mountains - Steep gradient v-shape valley · · vertical erosion > - forms gorges & canyons · Potholes = rounded hollows in bedrock created by vertical erosion : stones trapped in Riverbed -> steep gradient less steep gradient slow water speed corrasion , drills into rock - > deeper join together · hollows that vertical lateral erosion forming Istromstellen) rain · · erosion deltas Rapids : shallow water , steep gradient · Couter curve ( · straight channel transportation deposition - rocky & irregular river bed trough water gota meanders forming braided channel => & I waterfalls & X) middle & lower course gorges 1) horizontal layer of hard rock on top of layer of > - valley changes shape and widens , gentler slopes soft rock in river valley because of lateral erosion 2) Soft rock gets eroded more than hard forms > - gradient , Plunge pool lessens splashing water eddy (swirling movement /under cut hard rock & form > more - deposition than erosion 3) unsupported Overhang - > Overhang collapses > - vertical erosion may completely stop in lower course 4) more soft rock is eroded and process repeats > - Steep-sided valley called gorge develops over long time · 2) " - Process · water falls can bring major economic · benefits to an area : beautiful Scenery -> development in tourist industry (Victoria a Niagara Falls · they also bing disadvantages (navigation & crossing river 4  XI) meanders & oxbow lakes · meanders are : Sweeping bends in a river · occur in the middle & lower course · result of erosion and deposition how meanders & oxbow lakes form : neck narrow 2 t - - r - & deposition River ↑ through break gap lateral erosion River naturally flows in rivers is sent to the sides more erosion creates nar row neck a energy , > - > - corkscrew paltern, Fastest current is forced to outer curve, between two meanders , neck is it undercuts and erodes the bank helical flow cut through and river creates new & forming a river cliff Easter channel , old meander becomes an oxbow lake because deposition seals ends helical flow transports sediment from cliff across chankle to inner bank or slip-off slope , where water moves slower and deposits and forms 'small beach V1) Floodplains and levees XIII) Deltas floodplain : flat land next to a river , it's liable to flood Deltas occur when a river meets the sea or a lake. There are often small lakes within they are marshy and poorly drained. Flood plain is enclosed the delta. The river splits up and meet again , forming a braided channel. Deltas for m when by levees. river that's carrying i ts by mostly light-bedload meet still water. The loss of a n ow energy (speed) leads to deposition of the remaining load , which leads to forming the delta Levees formed river Hoods and the slows down a re naturally when a As a result , the heaviest part of the Bedload is deposited next Banks to the channel , making the higher Artificial levees are used in an attempt to stop flooding 5 Marine erosion hydraulic action : water is forced into cracks, corrasion : loose rocks (sediment) are thrown agains the compressing the air inside. cliff by the waves , wearing cliff away When the wave retreats , compress air blasts out corrosion : (chemical weathering) : seawater dissolves material from the rock. Mostly happing along limestone and chalk coasts when salt is dissolved attrition (wearing down) : loose sediment that's knocked off by hydraulic action and abrasion is swirled around by waves and collides with other sediment. It gradually gets wo r n down into smaller and rounder sediment 7