Landforms Resulting from Erosion

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Landforms Resulting from Erosion

-INTERLOCKING SPURS

-WATER FALLS

-GORGES

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WHAT ARE THE CHARACTERISTICS OF INTERLOCKING SPURS

-STEEP GRADIENT

-CONVEX SLOPES

-PROJECT FROM ALTERNATE SIDE OF THE VALLEY

-SEPARATED BY NARROW VALLEY FLOOR (USUALLY FILLED BY RIVER)

-SOMETIMES WOODED

-SOMETIMES HAVE SCREE SLOPES

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DESCRIBE THE FORMATION OF INTERLOCKING SPURS (STAG

- IN UPPERCOURSE RIVER USES MOST ENERGY OVER COMING FRICTION

- CHANNEL IS SHALLOW + NARROW

- ANY EROSION IS VERTICAL BY HYDRAULIC ACTION

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DESCRIBE THE FORMATION OF INTERLOCKING SPURS (STAG

- RIVER FOLLOWS WINDING PATHS

- AVOIDS OBSTRUCTIONS OF HARDER ROCK

- RIVER TAKES EASIEST ROUTE

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DESCRIBE THE FORMATION OF INTERLOCKING SPURS (STAG

- RESULTS IN PROJECTIONS OF HARD ROCK ENTERING VALLEY FROM BOTH SIDES

- PROJECTIONS ARE CALLED INTERLOCKING SPURS

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DESCRIBE THE FORMATION OF WATERFALLS (STAGE 1)

- RIVER MEETS BAND OF SOFTER LESS RESISTANT ROCK

- CALLED THE UNDERLYING

- SOFTER ROCK IS EROED AWAY MORE QUICKLY

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DESCRIBE THE FORMATION OF WATERFALLS (STAGE 2)

- PROCESSES OF EROSION SUCH AS ABRASION CAUSE UNDERCUTTING

- MORE RESISTANT ROCK IS LEFT UNSUPPORTED + OVERHANGS

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DESCRIBE THE FORMATION OF WATERFALLS (STAGE 3)

- WATERFALLS IS NOW FULLY ESTABLISHED

- GORGE IS CREATED AS THE WATERFALL MOVES FURTHER BACK

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DESCRIBE THE FORMATION OF GORGES

- WATERFALL ERODES SOFT ROCK UNDERNEATH

- CAUSES HARD FROCK TO FALL

- WATERFALL MOVES FURTHER BACK

- AS IT DOES THIS A GROGE IS CREATED

- THIS IS REPEATED OVER TIME + GORGE GETS BIGGER

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WHY THALWEG IS FASTER ON 1 SIDE OF RIVER CHANNEL T

- EXSISTING BEND IN RIVER

- OBSTRUCTION IN PART OF CHANNEL

- VARIATION IN CHANNEL DEPTH

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THALWEG

-FASTEST CURRENT OF THE RIVER

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HELICOIDAL FLOW

- CORCKSCREW MOTION OF THE WATER WHICH SENDS RIVER ENERGT TO ONE SIDE OF   THE MEANDER

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FORMATION OF MEANDERS (STAGE 1)

-LATERAL EROSION OCCURS THROUGH ABRASION + HYDRAULIC ACTION

- CAUSED BY THALWEG ON OUTSIDE BANK

- MAY HAVE ALREADY BEEN AN EXSISTING BEND IN THE RIVER + THALWEG DEVELOPS     THIS

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FORMATION OF MEANDERS (STAGE 2)

- RIVER CLIFF IS FORMED FROM WATER UNDERCUTTING 

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FORMATION OF MEANDERS (STAGE 3)

- HELICOIDAL FLOW ERODES OUTSIDE BANK

- MOVEMENT THEN DEPOSITS LOAD ON INSIDE BEND AS FLOW IS SLOWED BY FRICTION

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FORMATION OF MEANDERS (STAGE 4)

- RIVER BED DEEPENS DUE TO VERTICAL EROSION

- RESULTS IN AN ASYMMETRICAL CROSS PROFILE

- SLIP OF SLOPE IS FORMED WHEN SAND + PEBBLES ARE DEPOSITIED ON INSIDE OF         BANK

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OX- BOW LAKE FORMATION (STAGE 1)

- MEANDER LOOP BECOMES VERY LARGE

- ONLY NARROW STIP OF LAND SEPARATES MEANDER NECK

- CONTINUED LATERAL EROSION

- NECK BECOMES INCREASINGLY NARROW

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OX- BOW LAKE FORMATION (STAGE 2)

- RIVER FLOODS SO MAIN FLOW OF WATER CUTS STRAIGHT ACROSS NECK

-SHORT CUT BEGINS TO BREAK DOWN BANKS + CARVE NEW CHANNEL

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OX- BOW LAKE FORMATION (STAGE 3)

- FLOODS RECEDE + RIVER REVERTS TO NORMAL MEADNERING CHANNEL

- PROCESS REPEATS OVER TIME WITH EVERY FLOOD EVENT

- NEW CHANNEL BECOMES SO ESTABLISHED BY CONTINOUS LATERAL + VERTICAL            EROSION THAT IT BECOMES MAIN CHANNEL

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OX- BOW LAKE FORMATION (STAGE 4)

- LOOP OF OLD CHANNEL IS INCREASINGLY DETATCHED AS ITS NO LONGER RECIEVING   WATER

- SUBSEQUENT FLOODING CAUSES DEPOSITION ON RIVER BANKS AIDS DETACHMENT      OF OLD LOOP

-MARSH PLANTS COLONISE THE AREA WHICH FURTHER WIDENS THE GAP

- IN TIME ONLY FAR END OF MEANDER IS LEFT SOMETIMES SERVERAL METRES AWAY      FROM MAIN CHANNEL

- THIS IS THE OX-BOW LAKE

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