Weathering, Soil Erosion & Mass Wasting: Surface Processes Flashcards
When rocks are breaking into smaller pieces whether physically or chemically
Weathering
happens when rocks break up into tiny pieces without a change in their composition
Physical/Mechanical Weathering
Causes: frost wedging, water action, thermal stress, salt crystal growth, pressure release, gravity, exfoliation, plants and animals
Weathering
Examples of Physical Weathering
Frost weathering
Pressure-release
Abrasion
Organic Activity
Thermal expansion and contraction
process in which water freezes in a crack and then the expansion edges the rock apart
Frost weathering
process wherein tectonic forces lift deeply buried rocks close to the surface and then erosion removes the overlying rock, removing the pressure and causing the rock to expand and fracture
Pressure-release
process of grinding and rounding rock surfaces by friction and impact caused by waves and glaciers
Abrasion
process in which a rock is expanded by plant roots or broken by animal and human activities
Organic activity
occurs when temperature changes rapidly, causing the surface of the rock to heat or cool
Thermal expansion and contraction
happens when rocks break down into tiny pieces and change the rock’s composition or internal structure of minerals
Chemical weathering
some of its causes are oxidation, leaching, hydration, and carbonation
Chemical weathering
Types of chemical weathering
Dissolution
Hydrolysis
Oxidation
process in which a mineral or rock dissolves in water forming a solution like halite dissolved water
Dissolution
process in which mineral reacts with water to forma new mineral that has water as part of its crystal structure like feldspar to clay
Hydrolysis
process in which a mineral decomposes when it reacts with oxygen like rusting of iron
Oxidation
surface process characterized by the removal of rock particles from where they were formed
Soil Erosion
due to some agents such as water, wind, waves, rain, and ice
Soil erosion
major and universal agent of soil erosion
Running water
Causes: gravity, human activities (mining, logging, kaingin, burning grassland, infrastructure, and animals)
Soil Erosion
why does soil erosion reduce soil fertility?
because the topsoil which is rich in nutrients has been removed
bad effects of soil erosion
landslides, water shortages, deterioration of forests
Human activities that causes soil erosion
Kaingin farming or Burn method
Logging
Infrastructure projects
Mining
Overgrazing
farmers that don’t own lands for farming cut down trees and burn an area for planting their crops
Kaingin
after year of planting, the soil loses its fertility and farmers move on to other areas to have another __ without replanting the area
Kaingin
cutting down of trees for industrial purposes, some do not follow government regulations and some practice illegal logging, destroying forest covers
Logging
construction of roads, bridges, dams, etc., may cause soil erosion because of poor planning, inadequate provisions for drainage
Infrastructure Projects
digs and loosen rocks in the mountains and expose large areas to weathering and erosion
Mining
occurs in areas where there are farms for livestock where plants are consumed and eventually disappear, losing soil cover that may protect the area from landslides and flooding
Overgrazing
Methods to reduce effects of soil erosion
Rehabilitative method
Vegetative method
Mechanical method
Preventive Method
used in badly eroded areas
involves the use of vegetation and engineering structure
Rehabilitative method
Vegetative Methods
Cove cropping
Strip cropping
Contour tillage
Terracing
bare lands are planted with crops/crop rotation
Cover cropping
cultivated and uncultivated areas are plated alternately in rows
Strip cropping
soil is tilled across and not along the slopes
Contour tillage
slows down the flow of water; it prevents the formation of gullies, retains run-off water and protects human settler
Terracing
Advantages of cover cropping
Building soil health
Nutrient retention
Erosion control
Weed reduction
Mechanical methods
Riprapping
Farm ponds
usually done on a slope, covered with rocks fitted and cemented together
Riprapping
constructed on land depressions or holes to collect water and store it during the rainy season
Farm ponds
used in slightly eroded areas
involves forest fire prevention, proper land use, forest management, proper road construction and education of the people
Preventive Method
considered as the most important agents of erosion
transports, deposits weathered materials and brought by floods
Streams
prolonged rainfalls over several days, when intense rain falls over a short period of time, or when an ice or debris jam causes a river or stream to overflow onto the surrounding area
flood