weathering

Question 1

How/ why are glacial landscapes developed?

Answer 1

Due to a variety of interconnected climatic and geomorphic process: weathering and mass movement and glacial processes.

Question 2

weathering

Answer 2

• uses heat energy to produce physically or chemically altered materials from surface or near surface rock.
• The decay and disintegration of rock in situation
• weathering is significant in glaciated areas and influences the formation of the landscape
• physical, biological and chemical variations

Question 3

Bregschrund Crevasse

Answer 3

A big crack at back of glacier - as glacier moves, it breaks away as its brittle from the back wall and rocks can make their way through.

Question 4

physical weathering

Answer 4

freeze thaw
frost shattering
pressure release

Question 5

freeze thaw

Answer 5

• Rocks have cracks which water gets into
• Water freezes at 0 degrees and expands by 10%
• Extorting pressure, max. 2100 Kg/cm2 at -22 degrees (Avg pressure = 14 kg/ cm2)
• Exceeds most rocks resistance and the rocks cracks expand
• Water melts and those pieces are broken off
• Process repeats over and over in environments where temp fluctuations are common

Question 6

frost shattering

Answer 6

• All rocks have opening in them
• The openings may be pore spaces between grains, or networks of fractures
  Some of the openings will extend to the surface of the rock

Question 7

pressure release

Answer 7

• When the weight of overlying ice is lost due to melting the underlying rock expands
• This release of pressure causes the outside of the rock to crack and flake off
• parallel fractures are sometimes called bedding planes
• dilation is especially important when granite is exposed

Question 8

chemical weathering

Answer 8

Carbonation 
Hydrolysis 
Hydration 
Oxidation 
Solution

Question 9

carbonation

Answer 9

• Rainwater combines with dissolved co2 from atmosphere to produce a weak carbonic acid
• This reacts with calcium carbonate in rocks (limestone) to produce calcium bicarbonate
• soluble and washed away
• can be reversed and the dissolved minerals redeposited as stalagmites and stalactites
• effective in cold environments

Question 10

Hydrolysis

Answer 10

• Carbonic acid acts on rock containing silicon, replacing the silicon with ions of water
• The rock falls apart, what is left is clay
• Chemical process that creates the deep soil of the Amazon rainforest
• Feldspar creates clays and is the mist common weathering reaction on earth < sedimentary rock clay

Question 11

hydration

Answer 11

• Water molecules added to rock minerals create new materials of larger volume
• Hydration causes surface flaking in rocks as some minerals expand during the chemical change

Question 12

oxidation

Answer 12

• Some minerals in rock reach with 02 in air or water
• Iron is particularly susceptible to this process
• It becomes soluble under extremely acidic conditions and original structure is destroyed
• Often attacks the iron rich cement that bind the sand grains in sandstone responsible for rusting of metals

Question 13

solution

Answer 13

• Some salts are soluble in water
• Any process where a mineral dissolves in water is called solution
• carbonation is a mineral specific type of solution

Question 14

Van’t-Hoff’s Law

Answer 14

• Rate of most chemical reactions is faster when temps are higher
• Higher than 10 degrees -> 2.5x increase in reaction rates
• Chemical weathering -> effective in warm climates

Question 15

biological weathering

Answer 15

• Roots gradually grown into and open up joints in the rocks - during decay of organic material
• Organic acids are also released resulting in chelation
• weathering is limited due to the low temperatures

Question 16

Chelation

Answer 16

Complex biochemical processes, chelating agents are released from the decaying humans in the soil -> causes changes in chemicals structure of rock