Presentation on theme: "GLACIATION and RIVERS REVISION"— Presentation transcript:
1 GLACIATION and RIVERS REVISION Revise: how features formedHow to id on a mapLand useGathering techniques
2 Using the following description, draw the feature that is being explained. The river is meandering across the valley,(b) the river is eroding laterally (from side to side),(c) the river erodes the outside of the bends and deposits on the inside so its course is changing,(d) this erosion narrows the neck of the meander(e) often during a flood the river will cut through the neck,(f) the river continues in the new bed and the meander is abandoned,(g) new deposition seals off the ends and the cut-off becomes an ox-bow lake.
3 Using the diagrams, explain how the feature was formed River flows over an area where there are bands of softer and harder rocks,softer rock is more quickly eroded,the river undercuts the harder rock leaving an overhang,the river forms a plunge pool below the waterfall,overhanging rock is unsupported and falls into the plunge pool,the waterfall is moved upstream,as this process continues a gorge is cut back into the hillside.
6 What direction is the river flowing in? You may be asked to describe the physical features of a river an an OS map. The following points should be referred to in your answer:Examine the course of the river – is it straight or meandering? Is it in the upper, middle or lower section?What direction is the river flowing in?Look at the valley shape – is it V-shaped or is the river in its floodplain (contour lines will tell you)
7 Look at contour lines to work out the river’s speed eg if a river is flowing along flat ground, speed will be fairly slow.Pick out features of the river eg meanders, ox-bow lakes, waterfall etc … quote 6-fig grid references.
8 Describe the PHYSICAL features of the River Clyde and its Valley on the between and map extract marks G03
9 There are a number of lakes which may indicate drainage problems Describe the PHYSICAL features of the River Clyde and its Valley on the map extract marksClyde in this section is a winding/meandering river, generally flowing SE to NWThere are a number of lakes which may indicate drainage problemsGentle gradient (no contour lines)Valley floor/flood plain very wide (up to 0.5km)Valley sides gentler on the NW.Valley sides rise from 30 m to 100m
10 What do they tell you about the river? What are you looking at? Describe the physical features of the River Tees AND its valley from Basselton Wood to the road bridge circled.4 marksWhat do they tell you about the river?What are you looking at?What should I have mentioned?Both the valley and riverWide meanders, wide river in lower course, embankments to prevent flooding, abandoned meanders at Ox bow lake, tidal after barrage, wide floodplain further downstream
11 The Rivers Dee and Allt an t-Slugin and their valleys are very different. Describe these differences in detail marks C03
12 The River Dee is much wider than Allt being over 50 metres wide The Rivers Dee and Allt an t-Slugin and their valleys are very different. Describe these differences in detail marks C03The River Dee is much wider than Allt being over 50 metres wideThe floor of the River Dee is wide and flat, whereas the Allt is more V-shaped valleyA large area of the floodplain of the River Dee is marshy landThe Allt has a steeper gradient than the Dee, so probably flows fasterThe Dee flows east, while the Allt flows south eastThe Dee has steep slopes on the south side of the valley but the land on both sides of the Allt are very steep
13 Glaciation revision:With the aid of annotated diagrams describe and explain the processes involved in the formation of glaciated features, both erosional and depositional
15 Plucking Maximum erosion occurs where the weight of ice is the greatestPlucking happens when glacialice freezes and sticks to rock.Pluckingsteepens theBackwall.GlacierWhen the glacier moves, largeangular pieces of rock arepulled/plucked away with it.Mountain
16 AbrasionRocks carried by a glacier act like sandpaper, on a giant scale, rubbing against and wearing away the sides and floor of the valley. This leads to the valley getting steeper, deeper and wider. The bedrock is polished smooth by the ice as it moves across it.Rocks carried by the glacier grind at the base and sides of valleyWhere the ice flows over the rock it is polishedWhere the rocks scrape the rock striations are formed
18 Formation of a corrie a) snow collects in hollows b) snow compacts to icec) ice moves under gravity, lubricated by meltwaterd) ice rotates to lipe) abrasion deepens corrief) plucking steepens back and sidesg) corrie lochan (tarn) may fill hollow.
19 Formation of an areteSteep sided ridges which formed as the hollow deepened to form the corries.Frost shattering further sharpened the ridges leaving them rocky and jagged.
20 Formation of a pyramidal peak Steep sided frost isolated summits are formed when the backwall of 3 or more corries converge, mainly due to plucking action
21 Formation of a U-shaped valley Your Text HereFormation of a U-shaped valleyThe v-shaped valley is filled by a glacierThe glacier abrades the valley sides and plucks at the valley floorsThe interlocking spurs become steep sided truncated spursWhen the glacier reteats/melts a misfit stream or ribbon lake is left behindFormer tributaries become hanging valleys
24 MORAINES Pieces of rock picked up by glaciers are called moraines Terminal or end moraine, is found at the front of the glacier and marks the furthest extent of the advance of the glacier.Debris is pushed at the snout of the glacier and extends across trough.It is made up of unsorted clay, sand and rocks.MORAINES Pieces of rock picked up by glaciers are called moraines
25 drumlinDrumlins are smooth, elongated mounds of ground moraine or till which has been deposited by the ice but shaped while the ice was still moving.The steep side faces the icemovement.Drumlins often occur in swarms or groups.
26 Sorted sands and gravels description - This is a meandering ridge if sand and gravel. explanation - This feature is formed of sand and gravel deposited on the bed of a river flowing beneath the ice.EskerDrumlinTerminal MoraineKettle HoleTillOutwash PlainSorted sands and gravels