Geomorphologial Processes (sub-aerial)

Question 1

Marine processes e.gs

Answer 1

lsd (transportation), erosion and deposition

Question 2

Sub-aerial processes e.gs

Answer 2

Weathering, mass movement and run off

Question 3

Positive feedback

Answer 3

If the rate of debris removal exceeds the rate of weathering and mass movement then a positive feedback can operate, as the rate of weathering and mass movement could increase.

Question 4

Negative feedback

Answer 4

If debris removal is slow and ineffective, this will lead to a build-up of an apron of debris (scree) that reduced the exposure of the cliff face. Weathering and mass movement rates will decrease – negative feedback

Question 5

Mass movement

Answer 5

The downhill movement of weathered material under the force of gravity.
. Forms an impossible group of processes and flows within the coastal system transferring both energy (in response to gravity) and sediment
. Sediment forms an important input to shoreline process forming tools for erosion and providing material to be transported and deposited elsewhere along the coastline

Question 6

Physical weathering

Answer 6

. Involves the break-up of rocks without any chemical changes taking place
. Freeze thaw
. Salt crystallisation
. Wetting and drying

Question 7

Freeze thaw (physical weathering)

Answer 7

. Occurs when water enters a crack in the rock when
it rains and then freezes
. When water freezes, it expands in volume by about 10%
. This expansion exerts pressure on the rock, which
forces the crack to widen
. With repented freezing and thawing, fragments of rock break away and collect at the base of the cliff as scree
. These angular rock fragments are then used by the sea as tools in marine erosion
. Although the coast tends to be milder than inland
. Can trigger rockfalls

Question 8

Salt crystallisation (physical weathering)

Answer 8

. When salt water evaporates, it leaves salt crystals behind
. These can grow over time and exert stresses in the rock causing it to break up
. Salt can also corrode rock particularly if it contains traces of iron

Question 9

Wetting and drying (physical weathering)

Answer 9

. Frequent cycles of wetting and drying are common on the coast
. Rocks rich in clay expand when they get wet and
contract as they dry
.This can cause them to crack and break up

Question 10

Weathering

Answer 10

. Breakdown or disintegration of rock
weathering in situ (its original place) at or close to the ground surface
. As a process, weathering leads to the transfer (flow) of material

Question 11

Biological weathering

Answer 11

. The breakdown of rocks by organic activity is biological weathering
. Thin plant roots grow into small cracks in a chiff face. These cracks widen as the roots grow, which breaks up the rock
. Water running through decaying vegetation becomes acidic which leads to increased chemical weathering
. Birds (e.g. Puffins) and anilmals (e.g, rabbits) dig
burrows into cliffs
. Marine organisms are also capable of burrowing into rocks or of secreting acid

Question 12

Chemical weathering

Answer 12

Chemical weathering involves a chemical reaction where salts may be dissolved or a day-like deposit may result which is then easily eroded
. Carbonation
. Solution
. Oxidation

Question 13

Carbonation (chemical weathering)

Answer 13

. Rainwater absorbs carbon dioxide from the air to form a weak carbonic acid
. This reacts with calcium carbonate in rocks, such as limestone and chalk, to form calcium bicarbonate, which is easily dissolved
. The cooler the temperature of the rairwater, the
more carbon dioxide is absorbed (so carbonation is more effective in winter)
. Carbonation is an important part of the carbon cycle

Question 14

Oxidation (chemical weathering)

Question 15

Solution (chemical weathering)

Answer 15

. The dissolving of rock minerals, such as halite (rock salt).