Forces That Sculpture The Earth Flashcards
1
Q
- disintegration or alteration of rock in its natural or original position
- breaking down or dissolving of rocks and minerals on the surface of the Earth
A
WEATHERING
2
Q
TYPES OF WEATHERING:
- caused by the effect of changing temperature on rocks
- breaking down of rocks into smaller pieces without undergoing any change in mineral composition
A
Physical or Mechanical Weathering
3
Q
TYPES OF PHYSICAL OR MECHANICAL WEATHERING:
- usually occurs in mountainous regions like the Alps or Snowdonia
- happens when rainwater or snow-melt collects in rocks’ cracks then the water expands
A
Freeze-thaw
4
Q
TYPES OF PHYSICAL OR MECHANICAL WEATHERING
- occurs as cracks develop parallel to the land surface as a result of pressure reduction during uplift and erosion
- happens due to the combined effects of change in temperature and the expansion of minerals inside the rocks
A
✓ Exfoliation
5
Q
TYPES OF WEATHERING:
- caused by rain water (slightly acidic) reacting with the mineral grains in rocks to form new minerals and soluble salts
- occurs more rapidly at higher temperature like those in warm, and damp climatic regions
- first stage in soil formation
A
Chemical Weathering
6
Q
TYPES OF CHEMICAL WEATHERING;
- carbon dioxide in the air dissolves in rainwater making it weakly acidic
- weak carbonic acid is able to dissolve limestone as it seeps in the cracks and cavities, Acid Rain
- polluting gases like Sulphur dioxide and nitrogen dioxide dissolve in rainwater making it strong acid and when it attacks rocks, it leaves serious damage and breakdown
A
✓Solution
7
Q
TYPES OF CHEMICAL WEATHERING;
- breakdown of rocks by acidic water to form clay and soluble salt
- happens when acid rain reacts with rock- forming minerals like feldspar but quartz is the only common rock-forming mineral not affected by this Spheroidal Weathering
- rusty color
A
✓ Hydrolysis
8
Q
TYPES OF CHEMICAL WEATHERING
- breakdown of rock by oxygen and water, often giving iron-rich rocks a rusty colored weathered surface
A
✓ Oxidation
9
Q
TYPES OF WEATHERING:
- occurs when plants break up rocks with roots, prying the rock apart
- burrowing animals like badgers, moles and rabbits, burrow into rocks in search
- for shelter or food only refers to weathering caused by organisms such as animals, plants, fungi and microorganisms
A
Biological Weathering
10
Q
MAJOR CAUSES OF WEATHERING:
- occurs in the presence of water in regions with temperature near the freezing point (32 degrees Fahrenheit or 0 degrees Celsius)
- particularly common in Alpine areas and around the edges of glaciers
- when water seeps into a crevice in the rock and freezes, it expands causing deeper cracks and making rocks to eventually break apart
A
Frost Weathering
11
Q
MAJOR CAUSES OF WEATHERING:
- occurs when heat absorbed from the surrounding air causes a rock to expand; subsequent expansion and contraction when rock cools can cause thin sheets of rock’s outer layer to peel off
- moisture can also play a great role as well
- usually happens in desert areas where there is a variation in temperature suing night and day
A
Thermal Stress
12
Q
MAJOR CAUSES OF WEATHERING:
- caused when water get into rock in ways like up from a groundwater supply, action of seawater waves along rocky coast and downward through rainfall
- water evaporates, leaving salt behind which then crystallizes and the growing crystals can exert pressure on the rock that eventually break it
A
Salt Wedging
13
Q
MAJOR CAUSES OF WEATHERING:
- roots of trees and other plants can grow into small spaces and gaps between rocks, as they grow bigger they exert pressure on rocks around them causing a widening or gaps and cracks which result to breakdown microorganisms and lichens remove minerals from rocks making them weaker and when they are subjected to other forces
A
Biological Weathering
14
Q
FACTORS AFFECTING WEATHERING:
- rocks are subjected to weathering according to their composition; igneous are resistive to mechanical weathering but heavily affected by chemical weathering while some sedimentary rocks are subjected to mechanical weathering
- rate of weathering depends largely on the composition of the material that holds the grains together; rocks that are strongly jointed and fissured are more subjected to weathering than rocks with few cracks
A
Nature of Rock
15
Q
FACTORS AFFECTING WEATHERING:
- variation in climatic condition heavily affects the rapidness and slowness of weathering; regions with dry and cold climates tends to have relatively slow weathering processes compared to those regions with humid and warm climates
A
Climate