Cold KQ1 Flashcards
State some characteristics of a cold environment?
Ice
Ice streams
Little sunlight
State some landforms/plants/animals present in a cold environment?
Glaciers Ice caps Sea ice Iceberg Arctic meadow Musk Ox
Describe the climatic characteristics of a Glacial environment?
Snow and ice Very cold and dry Winter -70C Summer -40C Katabatic winds(cold mountain winds) form as dense air cools over central plateau drains into valleys
Describe the climatic characteristics of a Periglacial environment?
Lots of snow cover in high latitude/altitude
Winter -50C
Summer - 20C
Cold because of high latitude - small amount of insolation
High altitude
Albedo level high
What is Albedo?
Reflecting of solar radiation
40% reflected dark soils
90% reflected in snow or ice
Describe the climatic characteristics of a Mountain environment?
Once had snow and ice but not anymore
ONLY some…
Contain glaciers and ice caps
Why are HIGH LATITUDES cold?
Incoming solar radiation is spread out over a larger distance meaning that heating is less intense
Why are HIGH ALTITUDES cold?
As you go higher up in the atmosphere the pressure decreases
Less molecules and more space between them = less kinetic energy = colder temperatures
Why do WINDS cause cold?
Differences in air pressure cause wind
They happen in valleys and the wind cause a decrease in the temperature
How does ALBEDO reduce the suns heating?
High Albedo = high levels of reflection
Fresh snow = 0.9 meaning only 0.1 of radiation is absorbed
Surfaces with low albedos absorb radiation and heat up
Why do mountains experience high levels of PRECIPITATION?
2 types of air that mix and then this generates uplift = rain
Orographic rainfall - relief rainfall
Explain what a Ice Cap is?
Located in Antarctica and the Alps
Big sheets of ice - Antarctica is the biggest one on earth at 26.5 million cubic km
Explain what a Ice Stream is?
Rivers that flow into the ocean
Fast flowing corridor of ice
Explain what a Outlet Glacier (ice sheet) is?
Greenland - Jakobsharn Outlet - 2km deep - 65m long
River of ice flowing out of a glacier
Explain what a Valley Glacier is?
Switzerland
Glacier in a valley
Tributaries flowing into valleys, material from freeze thaw carried down the glacier leave lateral moraines
Crevasses help the glacier to move
Explain what a Cirque/Corrie Glacier is?
Small masses if ice found high up in the mountains
Piedmont Glaciers = look like elephants feet
Explain what mass balance is?
When ice masses are fed by snowfall in the winter and melt in the summer
Explain the mass balance diagram?
Accumulation (input) of snowfall + condensing of the snow with freezing then ablation (output) from solar radiation causes calving of icebergs, snow blowing off and evaporation
What is PLUCKING?
Ripping out of material from bed rock
Increased freeze thaw = increased plucking
Mainly downward pressure caused by the weight of the ice an down hill drag
Once prised it is used for abrasion
What is ABRASION?
“sandpaper effect”
Erosion caused by debris carried by the glacier
Larger and more angular rocks cause more damage
Chatter Marks - discontinuous scratch marks
Finer material just smooth’s the rocks
What is FREEZE THAW?
Pressure release, exfoliation and dilation
Release occurs during and after deglaciation
Starts with the removal of overglacier - decrease in weigh = expansion = cracks
Causes the expansion in the joints - dilation
Fractured rocks = more likely for freeze thaw weathering
What is CHEMICAL WEATHERING?
CO2 is very soluble at low temps = melt water streams - hold CO2 and become worse at weathering
Depends of the geology (fractures and joints) velocity of glacier (fast - more erosion) and amount of load (coarse load - more erosion)
Ice can actually protect the rock
What are the inputs in a glacier system?
Energy Precipitation Moraine Gravity Geothermal
What are the processes in a glacier system?
Ice movements
Erosion
Transportation
Deposition
What are the outputs in a glacier system?
Ablation - vapour
Calving - ice
Sediment - rock
Latent heat
What is the Mass Balance equation?
Balance (b) = accumulation (c) + ablation (a)
What does a positive mass balance mean?
More inputs than outputs = advancement
What does negative mass balance mean?
More outputs than inputs = retreat
Explain the transformation of snow to ice?
Snow is hexagonal
Weight of snow builds up and pressure causes compaction = snow to ice = neve
Deeper it is the more compression - forming a icy blue colour and forming solid interlocking grains - all the air is squeezed out
How is the Gorner Glacier in Switzerland changing?
Ice is still accumulating at the highest parts of the glacier
It is in negative mass balance
The spur of the valley has been abraded by ice to form the truncated spur
It is in retreat and the 2007-2008 ice melt meant that it retreated by 280 metres
What is the distribution of Ice caps and sheets?
Near mountain ranges
Arctic circle
Dispersed
Explain the reasons for the distribution of ice caps/sheets?
High latitude and altitude locations Minimal hours of sunlight Tilt of the earth Seasons Equator is closer - less distance to the sun Albedo
What is a cold based glacier?
Polar latitudes where temp of snow fall is below 0
So it remains frozen and has little movement or erosion
What is a warm based glacier?
Outside Antarctica and Greenland and water is present and acts as a lubricant
20-200m of movement a year
Greatly increasing the capacity of the glacier to erode the bedrock
What is the pressure melting point?
Temp at which ice is on the verge of melting
What is internal flow?
The movement within a glacier
What is basal slippage?
Sliding effect of a glacier over bed rock by a slip or creeps - caused by localised melting in the regelation layer
What is extensional flow?
Extension and related thinning of glacier ice and velocity increases
What is compression flow?
Reduction in the velocity and leads to an increase in thickness of the glacier
What makes a glacier move fast?
High accumulation of snow
Snow and ice thickness is above 60 metres
Steep glaciers flow faster
Impermeable surfaces - meaning melt water is retained - slippage
Amount of precipitation
What is the Firn line?
The equilibrium line
What are the factors that affect the amount of abrasion?
Speed of glacier Supply of debris Shape of debris Ice thickness Sub glacial melt water Debris removal Hardness of debris or bed rock
How are corries formed?
Frost shattering above glacier provides moronic debris
Abrasion by angular material - if pressure melting point is reached extra supply of water will reduce this
Plucking steepens the back wall and adds supply of debris
Rock lip where plucking also takes place
Widening of joints by pressure release - exaggerates the shape
Melt water flows down bergschrund and crevasses to the base of the glacier
Rotational movement occurs
What do cirques, glacial valleys and arêtes look like on a map?
Cirque - u-shaped close contour lines high up with an opening one side
Glacial Valleys - close contour lines representing the steep sides but spaced apart meaning a gentle slop in middle - sometimes have a river running through the middle
Arête - very closely packed contour line, high up with height increasing on both sides to a shaped central line
State some landforms in the Lake District?
Striding Edge - arête - think, knife edge ridge of rock - separates 2 valleys formed as a result of cirque glaciers cutting back - sharpened by freeze thaw
Gillercomb - hanging valley formed by a tributary valley it was a small glacier off a main one so less erosion
Langdale - u-shaped valley carved out by a glacier and its erosional processes of abrasion and plucking
What are till plains?
Unstratified, angular or sub angular fragments in clay matrix
Formed below a vast ice sheet covering Norfolk - Tills were deposited during and after the glacier melted
Found in North Norfolk - Overstrand
What are Drumlins?
A small hill in the shape of a spoon
During glaciation Lake district it happened many times and boulder clay was deposited
Found at Kendal Drumlins
What are Erratics?
An isolated crop of rock lying on top of a different type
Granite rocks were transported from Isle of Arran
Lake District
What are Moraines?
Deposits of angular rock fragments left after deglaciation
Lateral and medial moraines
Freeze thaw plucks the valley sides leading to the falling rock and then when the glacier melts it causes moraines to form
Found in Findel Glacier in Zermatt, Switzerland
What are Varves?
Laminated layers found in pro glacial lakes on ice margins
Deposits of thick sediment from glacier melts
Lakes in Sweden
What is an Esker?
Ridge of stratified deposits
Deposited in melt water
Blakeney Esker in Cromer
What is a Kame?
Umbrella term for all sorts and sizes of stratified melt water deposits including kettle holes
Irregular mounds of bedded sands and gravels
Talkin Tarn, Carlisle - deposits around a lake
